Concrete Calculator
Enter the length, width, and thickness of your slab and get the exact concrete volume — in cubic yards, cubic feet and cubic meters — plus how many bags you’ll need, with a 10% waste allowance built in.
Calculate your concrete
Enter the dimensions of your slab or pour.
Bag yields are approximate manufacturer averages (80-lb ≈ 0.60 ft³, 60-lb ≈ 0.45 ft³, 50-lb ≈ 0.375 ft³, 40-lb ≈ 0.30 ft³; 40-kg ≈ 0.022 m³, 25-kg ≈ 0.014 m³, 20-kg ≈ 0.011 m³) and vary by brand and mix. Counts cover the waste-adjusted order volume (your waste % above) and are rounded up, so you never run short.
- A 10 ft × 10 ft slab, 4 inches thick, takes 33.33 ft³ of concrete — 1.23 yd³, or 1.36 yd³ to order once the 10% waste allowance is added — and 62 × 80-lb bags to order (56 without the waste allowance).
- One cubic yard is 27 ft³: that is 45 × 80-lb bags, 60 × 60-lb bags or 90 × 40-lb bags — which is why the bags-vs-truck breakpoint matters on bigger pours.
- Always order extra: forms flex, the subgrade is never perfectly level and spills happen. The calculator builds in 10% waste and rounds bag counts up, so you never run short mid-pour.
Your pour, at a glance
A 3D look at your slab plus a side-by-side bag comparison.
Bigger bags mean fewer trips — an 80-lb bag covers about a third more volume than a 60-lb bag. Counts here cover the 1.36 yd³ order volume (10% waste included), not just the 1.23 yd³ base volume.
More measurement tools to try
Handy calculators for volume, numbers, and DIY math.
The complete guide to estimating concrete
Everything about figuring out how much concrete your project needs — the volume math for every shape, the waste allowance, and bags vs. ready-mix.
🧱How concrete volume is calculated
Concrete is ordered by volume: cubic yards (yd³) for ready-mix trucks, cubic feet (ft³) for bag math. The core idea never changes — length × width × height, in consistent units:
- Slab / wall / footing: V = length × width × thickness. A 10×10 ft slab, 4 in thick: 10 × 10 × (4÷12) = 33.33 ft³ ÷ 27 = 1.23 yd³.
- Round footing / column: V = π × (diameter÷2)2 × depth. A 12-in diameter hole, 36 in deep: π × 0.52 × 3 = 2.36 ft³; four of them = 9.42 ft³.
- Circular slab: V = π × (diameter÷2)2 × thickness. A 10-ft diameter patio, 4 in thick: π × 25 × (4÷12) = 26.18 ft³ = 0.97 yd³.
- Stairs: each step is a triangular prism: 0.5 × run × rise × width. Five steps at 11-in run, 7-in rise, 4-ft wide: 5 × 0.5 × (11÷12) × (7÷12) × 4 = 5.35 ft³, plus the platform (3 × 4 × 7÷12 = 7.00 ft³) = 12.35 ft³ total.
- Curb & gutter: V = (curb depth × curb width + gutter width × gutter thickness) × length. A 100-ft run with a 12 × 6 in curb face and a 24 × 6 in gutter flag: (1 × 0.5 + 2 × 0.5) × 100 = 150 ft³ = 5.56 yd³.
Every dimension above takes its own unit — feet, inches, yards, meters, centimeters or millimeters, mixed freely: a 3 × 3 m slab at 100 mm thick is 3 × 3 × 0.10 = 0.90 m³ (about 1.18 yd³). The #1 DIY error is mixing units — this calculator converts each field to a common unit before multiplying, so you don’t have to.
📐How much concrete do I need? The 4-step estimate
When someone asks me “how much concrete do I need?”, I never guess — I run the same four steps every time, and they are all this page does. However you describe the tool you were hunting for — a concrete yard calculator, a concrete calculator yards-and-bags combo, or a plain concrete estimator — the workflow is identical:
- Measure the pour: length × width × thickness, in feet and inches.
- Get the volume in cubic feet — that is the concrete volume calculator part, and the shape tabs above handle slabs, cylinders, walls, stairs and curb & gutter.
- Convert to yards: divide cubic feet by 27. This one division is the entire trick behind every concrete yardage calculator — a cubic yard is just a 3 ft × 3 ft × 3 ft cube.
- Add waste (covered in the next section) and decide: bags, or a ready-mix truck. If it is a truck, this page doubles as your ready mix concrete calculator — the “with waste” figure is the exact quantity I read out to the dispatcher.
My favourite shortcut: at 4 inches thick, one cubic yard covers 81 square feet. So when I am asked “how many yards of concrete do I need for a 400 ft² patio?”, I divide 400 by 81 and get 4.94 yd³ — before waste. The full worked answers for the most common slab sizes are in the slab section below.
🧮How to calculate concrete: the formula box
If you would rather run the numbers on paper, here is how to calculate concrete for every shape this page handles — the exact concrete calculator formula set I use, with nothing hidden:
- Slab or pad: volume (ft³) = length × width × (thickness in inches ÷ 12)
- Cylinder (post hole, pier): volume = π × (diameter ÷ 2)² × depth, all in feet
- Strip footing: volume = length × width × depth, all in feet
- Cubic yards: yd³ = ft³ ÷ 27
- Bags: bags = ft³ ÷ yield per bag (approx. 0.60 / 0.45 / 0.375 / 0.30 ft³ for 80 / 60 / 50 / 40-lb bags), always rounded up; metric bags divide m³ by the approx. yield (0.022 / 0.014 / 0.011 m³ for 40 / 25 / 20-kg bags)
- Order quantity: yd³ × 1.10 for a 10% waste allowance
Sanity-check it against the calculator: a 12 × 12 ft pad at 4 inches is 12 × 12 × (4 ÷ 12) = 48 ft³, which is 1.78 yd³, or 1.96 yd³ to order — exactly what the tool reports.
🚙Slab & pad mode: patios, pads and driveways
I built this page first and foremost as a concrete slab calculator, because the flat rectangle is 90% of DIY pours — and the same Slab tab works as a concrete pad calculator for the smaller stuff: an AC unit pad, a hot-tub base, a shed floor. A pad is just a slab that sweats less: same math, usually 4 inches thick, just smaller numbers (a 3 × 3 ft equipment pad at 4 inches is 3 ft³ — five 80-lb bags).
Where the slab tab earns its keep is driveways. When I use this as a concrete driveway calculator, the pour I quote most is a 20 × 20 ft double driveway: at 4 inches thick it takes 133.33 ft³ = 4.94 yd³, so I order 5.43 yd³ with waste. If trucks or an RV will park on it, I go to 6 inches — 200 ft³ = 7.41 yd³, 8.15 yd³ to order. In bags, the 4-inch version is 223 eighty-pounders, which is why driveways are truck work, full stop.
| Slab, 4 in thick | Volume | Order (+10%) | 80-lb bags to order |
|---|---|---|---|
| 10 × 10 ft patio | 1.23 yd³ | 1.36 yd³ | 62 |
| 12 × 12 ft patio | 1.78 yd³ | 1.96 yd³ | 88 |
| 20 × 20 ft driveway | 4.94 yd³ | 5.43 yd³ | 245 |
Those three sizes answer most of the “how much for my slab” questions I get — scale from the nearest row, then confirm with your exact measurements above.
📦The waste allowance: why 10% is standard
Order more than the math says. Forms flex, subgrades are never perfectly level, wheelbarrows spill, and a short load means an expensive second delivery — or a cold joint weakening your slab. 10% covers normal variance for straightforward pours; use 5% only for machine-graded commercial work and up to 15–25% for rough, hand-dug footings.
On the 10×10×4-in slab: 1.23 yd³ × 1.10 = 1.36 yd³ to order. Adjust the waste % above and watch the order amount — and the cost estimate — update. Leftover concrete is cheap insurance; a short pour is not.
🎒Bags vs. ready-mix: the breakpoint
Bagged concrete (80/60/40-lb bags yielding ~0.60/0.45/0.30 ft³) suits small pours; ready-mix trucks suit big ones. The breakpoint sits around 1–2 yd³:
| Project | Volume | 80-lb bags (base volume, without waste) | Best option |
|---|---|---|---|
| Fence post footing | 2.36 ft³ | 4 | Bags, obviously |
| 10×10 ft patio, 4 in | 1.23 yd³ | 56 | Bags (long day) or short-load truck |
| 20×20 ft driveway, 4 in | 4.94 yd³ | 223 | Ready-mix truck |
Mixing 56 bags by hand is a full brutal day for two people; a truck pours it in 20 minutes. But trucks charge short-load fees under ~4 yd³ and can’t reach everywhere — a wheelbarrow relay from the curb has limits. Price both: enter your $/yd³ above for the ready-mix estimate (1.36 yd³ at $150/yd³ = $204).
🛒Bag mode: how many bags?
Scroll up and the results panel doubles as a concrete bag calculator: alongside the yardage, the concrete calculator bags breakdown shows 80, 60, 50 and 40-lb counts — plus metric 40, 25 and 20-kg counts — for your exact pour. Everything starts from one number per size — what a single bag of concrete yields once it is mixed and placed. These are the manufacturers’ published yields, and they hold for every major brand:
| Bag size | Yield per bag | Bags per cubic yard |
|---|---|---|
| 80-lb bag | 0.60 ft³ | 45 |
| 60-lb bag | 0.45 ft³ | 60 |
| 50-lb bag | 0.375 ft³ | 72 |
| 40-lb bag | 0.30 ft³ | 90 |
The version of the question I hear most is “an 80 lb bag of concrete — cubic feet?”, and the answer is that 0.60 ft³ row. Flip it around and you get the answer to how many bags of concrete in a yard: 45 of the 80-lb bags, 60 of the 60-lb, 72 of the 50-lb, or 90 of the 40-lb.
Metric bags work the same way: a 40-kg bag yields ≈ 0.022 m³ (about 45 bags per m³), a 25-kg bag ≈ 0.014 m³ (about 71 per m³), and a 20-kg bag ≈ 0.011 m³ (about 91 per m³) — approximate nominal yields that vary by brand and mix, and the breakdown above counts them for your pour too.
My honest breakeven advice: a yard of concrete in 80-lb bags costs roughly $250–$290 in material at typical home-center prices (about $5.50–$6.50 a bag), before you have lifted a single one — and 45 bags is 3,600 lb you will move at least twice. Below about half a yard, bags win easily. Past a yard, I price a truck every time, short-load fee and all.
💰What concrete costs: yards, slabs and square feet
Two versions of the same question land on this page every day — “how much is a yard of concrete?” and “how much is concrete per yard?” — so here is the answer I work from. On the price checks I ran across US ready-mix suppliers in October 2026, a standard delivered mix runs about $130–$180 per cubic yard before fees (a survey range, not a quote — your plant’s price is the real one). Delivery is extra, and orders under about 4 yd³ usually attract a short-load fee of $50–$150, which is why how much does a yard of concrete cost has two answers: $130–$180 in a full load, but effectively $230–$330 for a single yard delivered on its own.
Per-square-foot thinkers ask “how much is concrete per square foot?” Material only, the math is simple: a yard covers 81 ft² at 4 inches, so $130–$180 a yard is $1.60–$2.22 per ft²; at 6 inches a yard covers 54 ft², so $2.41–$3.33 per ft². (A finished, hired-out slab is a different budget entirely — forming, placing and finishing labour commonly takes the installed total to $8–$18 per ft².)
Here is how I use this page as a concrete slab cost calculator: take the 20 × 20 driveway from the slab section — 5.43 yd³ with waste. Plants round orders to the nearest quarter yard, so call it 5.5 yd³; at a mid-range $150 a yard that is $825 for the concrete itself. That is all a concrete cost calculator is really doing — order quantity × delivered price — and you do not have to do it by hand: the concrete calculator cost input at the top of this page (the “Price per yd³” field) multiplies your pour by your local price automatically.
🧪Mix ratios: 1:2:4 and friends
A naming trap first, because I see it constantly: people go looking for a cement calculator when they mean concrete. Cement is one ingredient — the grey powder that glues everything together. Concrete is the finished material: cement + sand + coarse aggregate + water. If you are batching from raw materials instead of buying bags, the tool you actually want is a concrete mix calculator, and the recipe is written as a ratio — 1:2:4 means 1 part cement, 2 parts sand, 4 parts aggregate, all by volume.
| Nominal mix | What I use it for | Cement per yd³ placed |
|---|---|---|
| 1:3:6 (M10) | Blinding and levelling layers under footings | ≈4.2 bags |
| 1:2:4 (M15) | General purpose — slabs, paths, post setting | ≈5.9 bags |
| 1:1.5:3 (M20) | Reinforced work — driveways, beams, lintels | ≈7.6 bags |
| 1:1:2 (M25) | Heavy-duty structural work | ≈10.4 bags |
Here is the 1:2:4 concrete mix calculator math I run for one finished cubic yard. Loose dry ingredients take up more room than the placed concrete — the conventional dry-volume factor is 1.54 — so I start with 27 × 1.54 ≈ 41.6 ft³ of dry material. Seven parts total: cement gets 41.6 ÷ 7 ≈ 5.9 ft³ (about 558 lb, or six 94-lb bags), sand gets 11.9 ft³ (0.44 yd³), and aggregate gets 23.8 ft³ (0.88 yd³), with roughly 30 gallons of water added gradually — about 5 gallons per bag of cement. Scaling down, one 94-lb bag of cement (1 ft³) with 2 ft³ of sand and 4 ft³ of stone yields about 4.5 ft³ of placed concrete — enough for roughly two standard post holes.
🕳️Footings & post holes
The Wall / Footing shape above turns this page into a concrete footing calculator: a strip footing is just a long, low box — length × width × depth. As a footing calculator it earns its keep on runs like this one: a 40-ft footing, 16 inches wide and 8 inches deep, is 40 × 1.33 × 0.67 = 35.6 ft³ = 1.32 yd³, so I order 1.45 yd³ with waste. In bags that same footing is 60 eighty-pounders — mixer or truck territory for most of us. (And a vocabulary note, because half the country searches for a concrete footer calculator: “footer” and “footing” are the same pour. The math does not care which word you use.)
Post holes are the other footing job, and a post hole is a cylinder — which makes the Round Footing shape a concrete cylinder calculator: volume = π × radius² × depth. This is the post hole concrete calculator work I do most: a 10-inch diameter hole, 30 inches deep, holds π × (5÷12)² × 2.5 = 1.36 ft³ gross. What most people forget is displacement — the 4×4 post sitting in that hole is really 3.5 inches square, and it pushes out about 0.21 ft³ of concrete below grade. Net, I need ≈1.15 ft³ per hole, which is 2 eighty-lb bags. An eight-post fence line works out to about 9.2 ft³ net — 16 bags, a very doable Saturday.
⚖️Weight of concrete: the trailer problem
The weight of concrete is the number that wrecks DIY logistics: normal-weight concrete runs about 150 lb per cubic foot — roughly 4,050 lb per cubic yard. That modest little 10 × 10 patio from the examples? 33.33 ft³ × 150 = 5,000 lb of finished slab. Even half a yard is 2,025 lb, more than the payload of most single-axle utility trailers (commonly 1,500–2,000 lb) — which is why concrete arrives by truck, or in bags you carry a few at a time. It is also a good sanity check on bag math: a yard built from 80-lb bags starts as 45 × 80 = 3,600 lb of dry mix, before the mixing water. However you buy it, plan for the weight first and the volume second.
📏Thickness by project
Thickness is structural, not decorative:
- Walkways & patios: 4 in — enough for foot traffic on a compacted base.
- Driveways: 4–6 in — 6 in if heavy vehicles or soft soil; consider rebar or wire mesh.
- Footings & foundations: 6–12 in, below the frost line in cold climates.
- Stairs: 4-in minimum tread depth over the triangular steps.
Every extra inch on a 10×10 slab adds 10 × 10 × (1÷12) = 8.33 ft³ (0.31 yd³) — about 14 extra 80-lb bags. Thickness is the cheapest strength you can buy, until it isn’t: don’t pour structural footings without checking local code.
🚧Ordering tips that save money and stress
- Measure twice, in the same units. Confirm length, width, and depth after forms are built — a form that bowed out an inch changes the volume.
- Call the plant with your number. Dispatchers sanity-check DIY math daily and will flag a bad measurement.
- Plan the pour order. Concrete waits for no one: have forms, rebar, tools, and help staged before the truck arrives.
- Weather matters. Above ~90°F concrete sets fast (order retarder or pour early); below ~40°F it needs protection to cure.
- Round up, not down. Bag counts here already round up — for ready-mix, most pros round the order to the nearest quarter yard up.
❓Irregular shapes and odd pours
Not everything is a rectangle. Break complex pours into simple shapes and add the volumes: an L-shaped patio is two rectangles; a curved edge can be approximated with a series of rectangles (or use the circular slab mode for true arcs). For footings, count each one and use the quantity multiplier — four 12-in × 36-in footings need 9.42 ft³ (16 eighty-pound bags). When in doubt, sketch it, split it, sum it — and keep the 10% waste on the total.
How to estimate your concrete
Three steps, instant bag count.
Measure length, width and thickness — every field takes its own unit, from millimeters to yards.
Type all three numbers — the math updates live.
Cubic yards for a ready-mix order, or bag counts for DIY.
Curing and finishing: what happens after the pour
The pour is half the job. Strength is made in the days after it, and lost just as quietly.
Concrete does not dry into strength; it cures into it. The cement in the mix reacts with water in a slow chemical process, and that process needs water present and temperatures reasonable for days after placing. Let the surface dry out in sun and wind, and the reaction stalls at the surface, leaving a weak, dusty skin over sound concrete below. Curing is simply the work of keeping the concrete damp and protected while the reaction runs: cover it, wet it, or seal it, and keep doing it longer than feels necessary. The commonly used reference point is the 28-day strength — the strength a mix is specified and tested against — but most of the gain that matters on a home project happens in the first week, which is why the first week is the one to protect.
Finishing, in order. Screed first: drag a straight edge across the forms to strike the concrete level. Float next: work the surface just enough to embed the aggregate and bring up a thin layer of paste. Edge and joint while the concrete is still workable: tool the edges and cut control joints where the slab is meant to crack in a controlled line rather than at random. Broom or trowel last, according to the finish wanted — a broom finish for grip outdoors, a smooth trowel finish where grip matters less. The mistake at every stage is the same one: overworking the surface. Too much floating or trowelling brings too much water and fine material to the top, and the finished skin flakes and dusts. Do each step once, well, and leave it alone.
Weather changes the rules. In heat, concrete sets faster, water leaves faster, and the window for finishing shrinks — pour early, keep the surface damp, and protect it from sun and wind. In cold, setting slows, and concrete that freezes before it has gained strength is damaged permanently, not merely delayed. The specification or the supplier sets the limits for a given mix; the planning point here is that the same pour in July and in January is not the same job, and the curing plan, not the volume, is what changes. Footings, sonotubes, and post holes have their own measuring problems before any of this begins — the companion guide works those shapes end to end — and mix ratios and grades, the other half of getting the material right, are covered in the companion guide on ratios and grades.
Cost factors, without the guesswork
Five things set the price of a pour. Only one of them is the price of the concrete itself.
Ready-mix or bags. Small pours are usually bag work and large pours are usually truck work, and the crossover is decided by volume and by access, not by preference: the guide above shows the bag count per yard, and once the count runs into the hundreds, mixing by hand is no longer a saving. Delivery and short loads. A truck that arrives part-empty may carry a short-load fee, and the fee can rival the material on a single yard — the cost section above shows the typical ranges this page works with. Access. A pump, a wheelbarrow run, or a long chute each cost time and money, and a site the truck cannot reach is a different job from one it can. Reinforcement and preparation. Rebar or mesh, the compacted base, and the formwork are real costs that the volume figure never shows. Labour and finishing. Placing, screeding, and finishing take hands, and a large pour needs them all at once, because concrete waits for no one. Price the whole job — material, delivery, access, preparation, and labour — and compare quotes on the same inclusions, or the cheapest quote is simply the one that left the most out.
🧮How concrete volume is calculated
A concrete slab is a rectangular box. Volume is length × width × thickness — with thickness converted from inches to feet first:
cubic yards = cubic feet ÷ 27
order amount = cubic yards × 1.10 (10% waste)
80-lb bags = ceil(order ft³ ÷ 0.60) · 60-lb = ceil(order ft³ ÷ 0.45) · 50-lb = ceil(order ft³ ÷ 0.375) · 40-lb = ceil(order ft³ ÷ 0.30) · 40-kg = ceil(order m³ ÷ 0.022) · 25-kg = ceil(order m³ ÷ 0.014) · 20-kg = ceil(order m³ ÷ 0.011)
Worked example: a 10 ft × 10 ft slab, 4 inches thick → 10 × 10 × (4 ÷ 12) = 33.33 ft³ → ÷ 27 = 1.23 yd³ → × 1.10 = 1.36 yd³ to order → ceil(36.67 ÷ 0.60) = 62 × 80-lb bags to order.
Yes, for almost every pour. Form boards flex outward, the subgrade is never perfectly level, some concrete sticks to the wheelbarrow and forms, and spills happen. Ordering the exact calculated volume means you run short — and a second, small ready-mix load is expensive. The industry rule of thumb is 5–10% extra; this calculator uses 10% so a DIY pour is covered either way. Bag counts are also rounded up to whole bags.
It depends on your crew and your mixer. An 80-lb bag yields about 0.60 ft³ — fewest bags and the best price per cubic foot, but it is a two-person lift for most people. 60-lb bags (≈0.45 ft³) are the sweet spot for solo DIY: manageable weight, widely stocked. 40-lb bags (≈0.30 ft³) are easiest to carry but you will buy roughly twice as many as 80-lb bags for the same pour. If your total is under about 2 yd³, bags usually beat a ready-mix truck’s short-load fee.
Thickness is the number people get wrong most often — it drives the whole volume. Typical minimums: garden paths and sidewalks: 4 inches; patios and shed slabs: 4 inches; driveways for cars: 4–5 inches; driveways for trucks or RVs: 6 inches; footings and posts: 6–8+ inches. Always measure the actual form depth after the base is compacted, not the nominal lumber size.
Frequently asked questions
Why add 10% waste — is it really needed?
Yes for most DIY pours. Forms flex, ground is uneven, and spills happen — a short load means a costly second delivery or a weak cold joint. Adjust the percentage above for your situation (5% for pro-graded work, up to 25% for rough footings).
Which bag size should you buy?
80-lb bags mean the fewest bags and trips (56 for the example slab vs 112 forty-pounders, without waste allowance), but each bag is heavy. Choose 60- or 40-lb bags if you’re mixing alone. With the standard 10% waste allowance, order 62 eighty-lb bags vs 123 forty-lb bags. Yields: ~0.60 / 0.45 / 0.30 ft³.
What thickness do common projects need?
Walkways and patios: 4 in. Driveways: 4–6 in. Footings: 6–12 in below frost line. Every extra inch on a 10×10 slab adds ~8.33 ft³ (about fourteen 80-lb bags).
How many bags of concrete do I need for a 10×10 slab 4 inches thick?
33.33 ft³ ÷ 0.60 = 56 eighty-lb bags (rounded up) without waste allowance; 75 sixty-lb, or 112 forty-lb bags on the same base volume. With the standard 10% waste allowance, order 62 eighty-lb bags, or 82 sixty-lb, or 123 forty-lb bags.
How do you calculate cubic yards of concrete?
Length × width × thickness in feet, divided by 27. For round shapes use π × radius² × depth. Then add your waste allowance.
How many 80-lb bags make one cubic yard?
27 ft³ ÷ 0.60 ft³ per bag = 45 bags (about 45).
Should I use bags or order ready-mix concrete?
Under ~1 yd³, bags. Over ~2 yd³, a truck is cheaper and far faster. Between 1–2 yd³, price both — watch for short-load fees on small truck orders.
What if my pour isn’t a simple rectangle?
Use the shape tabs above: round footings, circular slabs, walls, stairs, and curb & gutter are all built in. For L-shapes or curves, split the pour into simple shapes and add the volumes.
Why does the calculator ask for thickness in inches?
Because that’s how the trade talks (a “4-inch slab”). The calculator converts to feet internally before multiplying — and every field has a unit selector, so you can enter millimeters or centimeters instead if you prefer.
How do I estimate a round footing?
Volume = π × (diameter÷2)² × depth. A 12-inch diameter hole 36 inches deep holds 2.36 ft³ — about four 80-lb bags. Enter the quantity for multiple identical footings.
Can I use metric units?
Yes — every dimension field has its own unit selector (feet, inches, yards, meters, centimeters or millimeters) and the results include cubic meters, so a 3×3 m slab at 100 mm = 0.90 m³. Metric bag counts (40, 25 and 20 kg) are included too, using approximate nominal yields.
How much does concrete cost?
Ready-mix commonly runs $130–$180 per cubic yard plus delivery/short-load fees. Enter your local $/yd³ above for an estimate on your pour.
How many bags of concrete are in a yard?
One cubic yard is 27 ft³, so at the manufacturers’ published yields it takes 45 × 80-lb bags (0.60 ft³ each), 60 × 60-lb bags (0.45 ft³), 72 × 50-lb bags (0.375 ft³) or 90 × 40-lb bags (0.30 ft³). That is why the bags-vs-truck breakpoint matters — a yard of bags is 45 heavy lifts before you have mixed anything.
How much does a yard of concrete cost?
For ready-mix, US supplier listings checked in October 2026 put a standard delivered mix at about $130–$180 per cubic yard before fees. Delivery plus a short-load fee (commonly $50–$150 on orders under about 4 yd³) is extra, so a single yard on its own can effectively cost $230–$330. Bought as bags instead, one yard is 45 × 80-lb bags — roughly $250–$290 of material at typical home-center prices.
How long should concrete cure before I walk or drive on it?
Light foot traffic is commonly allowed after about 24 hours, and driving is commonly held off for about a week, with full strength developing over about 28 days. These are common practice figures, not a specification: cold weather slows curing, and a structural pour follows the specification or the supplier’s advice, not a rule of thumb. Keep the surface damp and protected during the first week either way.
Does curing change how much concrete I need?
No. Curing changes strength, not volume. The volume is set by the form dimensions, plus the waste allowance for flex, uneven ground, and spills. What curing changes is whether the volume you placed reaches the strength the mix was specified for, which is why a short pour that is cured well outperforms a full pour that is left to dry out.
What is the difference between curing and drying?
Drying is water leaving the concrete. Curing is the chemical reaction between cement and water that builds strength, and it needs water present to run. A slab that dries out too fast has not cured; it has stalled, usually at the surface, leaving a weak skin. Curing is therefore the opposite of drying in practice: cover, wet, or seal the surface to keep the reaction going.
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Related guides
In-depth guides to yards, bags, trucks and pours.
Ready-mix prices, delivery and short-load fees.
Drum sizes, legal loads and short-load math.
4,050 lb a yard — and what that means for hauling.
Yield per bag and bags per yard, size by size.
1:2:4, M20 and M25, and what PSI means.
Round holes, strip footings, and the waste allowance.