Resistor Calculator — Read Any 4-Band, 5-Band or 6-Band Color Code
Pick the colors on the resistor and get its resistance in ohms, kΩ, or MΩ — with tolerance and the real min/max range.
Read the bands
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The value
Reverse — value → colors
Your resistor, drawn
The bands below mirror your picks exactly — change any dropdown and the resistor redraws. The tolerance band sits apart, just like the real component.
- Each color is a digit — black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, gray 8, white 9 — and on a 4-band resistor the first two bands are digits and the third is a power-of-ten multiplier.
- The default bands — yellow, violet, red, gold — read 47 × 100 = 4,700 Ω (4.7 kΩ) at ±5% tolerance.
- In series the resistances simply add; in parallel the reciprocals add, so the total always lands below the smallest resistor in the group.
Pick the colors on the resistor and get its resistance in ohms, kΩ, or MΩ — with tolerance and the real min/max range. Or flip it around: type a value and see which bands to look for.
The resistor bench
Two bench tools that live next to the color code: combine resistors in series or parallel, and work out the resistance of a plain length of wire.
Series & parallel
The combination
Wire resistance
| Material | ρ at 20 °C (× 10⁻⁸ Ω·m) |
| Silver | 1.59 |
| Copper | 1.68 |
| Gold | 2.44 |
| Aluminum | 2.65 |
| Tungsten | 5.60 |
| Iron | 9.71 |
| Platinum | 10.60 |
| Nichrome (Ni, Fe, Cr alloy) | 100.00 |
The wire
Keep exploring
Three companion tools for math and study.
How it works
Three steps from stripes to ohms.
Pick the band count
Most carbon-film resistors have 4 bands; precision metal-film parts usually have 5, and 6-band parts add a temperature-coefficient band.
Set each color
Digits first, then the multiplier, then tolerance — the dropdowns tint to match your pick.
Read the value
Resistance in Ω, kΩ, or MΩ, plus the tolerance window your part can actually measure.
The math behind the color code
Each color is a digit: black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, gray 8, white 9. On a 4-band resistor the first two bands are digits and the third is a power-of-ten multiplier. A 5-band resistor adds a third digit for precision. The last band is tolerance — how far the real value may drift from the printed one.
Worked examples:
| Bands | Calculation | Result |
|---|---|---|
| Yellow · Violet · Red · Gold (4) | 47 × 10² = 4,700 Ω | 4.7 kΩ ±5% (4.465–4.935 kΩ) |
| Brown · Black · Black · Red · Brown (5) | 100 × 10² = 10,000 Ω | 10 kΩ ±1% (9.9–10.1 kΩ) |
| Red · Red · Brown · Gold (4) | 22 × 10¹ = 220 Ω | 220 Ω ±5% (209–231 Ω) |
| Orange · Orange · Silver · Silver (4) | 33 × 10⁻² = 0.33 Ω | 0.33 Ω ±10% |
Go deeper
Reading direction, odd bands, and what tolerance really costs you.
- Digits: black 0 · brown 1 · red 2 · orange 3 · yellow 4 · green 5 · blue 6 · violet 7 · gray 8 · white 9.
- Multipliers: the same colors as powers of ten, plus gold ×0.1 and silver ×0.01 for small values under 10 Ω.
- Tolerances: brown ±1% · red ±2% · green ±0.5% · blue ±0.25% · violet ±0.1% · gold ±5% · silver ±10% · no band ±20%.
- Temperature coefficient (the 6th band): black 250 · brown 100 · red 50 · orange 15 · yellow 25 · green 20 · blue 10 · violet 5 · gray 1 ppm/°C — how many parts per million the resistance drifts for each degree Celsius of temperature change.
- Memory hook: the digit order follows the rainbow from black and brown up through red, orange, yellow, green, blue, and violet to gray and white.
Reading a resistor backwards gives a nonsense value, so manufacturers build in clues:
- The tolerance band sits apart: it is spaced away from the others, or placed after a wider gap — read from the opposite end.
- Gold and silver never start: neither color is a valid first digit, so if one end is gold or silver, that end is last (multiplier or tolerance).
- Tolerance is a promise window: a 4.7 kΩ ±5% part may measure anywhere from 4.465 kΩ to 4.935 kΩ and still be in spec — design circuits that tolerate the whole window.
- 6-band parts add a temperature-coefficient band (drift per °C) — this calculator covers the standard 4-, 5- and 6-band values.
Frequently asked questions
Quick answers about this resistor calculator.
How do I read a 4-band resistor?
The first two bands are digits, the third is the multiplier, and the fourth is tolerance. Yellow-violet-red-gold reads 47 × 100 = 4,700 Ω (4.7 kΩ) with ±5% tolerance.
How do I read a 5-band resistor?
The first three bands are digits, the fourth is the multiplier, and the fifth is tolerance. Brown-black-black-red-brown reads 100 × 100 = 10,000 Ω (10 kΩ) at ±1% — the extra digit is why 5-band parts are used for precision values.
Which end of the resistor do I start from?
Start opposite the tolerance band. It is usually spaced apart from the others, and gold or silver can never be a first digit — so if one end shows gold or silver, read from the other end.
What do gold and silver bands mean?
As a multiplier, gold means ×0.1 and silver means ×0.01 — they make values under 10 Ω possible. As the last band, gold means ±5% tolerance and silver means ±10%; no tolerance band at all means ±20%.
How do I find the colors for a value I need?
Use the reverse box in the calculator: type the resistance, pick Ω, kΩ, or MΩ, and it shows the closest standard 4-band code — 4,700 Ω gives yellow, violet, red, with gold for ±5%.
What does tolerance mean for my circuit?
Tolerance is the window the real resistance can fall in: a 4.7 kΩ ±5% part can measure from 4.465 kΩ to 4.935 kΩ. If your circuit is sensitive — a voltage divider feeding a sensor, say — choose a tighter tolerance like ±1% brown.
What is the 6th band on a resistor?
The 6th band, found on precision resistors, is the temperature coefficient — how much the resistance drifts as temperature changes, in parts per million per °C. Brown (100 ppm/°C) is the most common: a 47 kΩ resistor with a brown 6th band drifts about ±47 Ω for every 10 °C. Tight designs use red (50), blue (10) or violet (5); gray (1 ppm/°C) is the most stable of all. Switch the reader above to 6-band to decode one.
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Disclaimer
This calculator decodes the standard 4-band, 5-band and 6-band color codes for information and study. Faded, heat-damaged, or non-standard parts can be misread — when a value matters, confirm it with a multimeter before soldering the part into a circuit.