Roman Numeral Converter
Convert any number from 1 to 3,999,999 into Roman numerals (a vinculum bar carries you past 3,999) — paste Roman numerals to get the number back, convert a date, and see a symbol-by-symbol breakdown of every result.
Convert Roman numerals
Pick a direction, type a value and convert — the Roman Date tab turns a Roman date back into a numeric date, or open the Batch tab to convert a whole list at once.
- Seven symbols and six subtractive pairs build every Roman numeral from 1 to 3,999 — and a vinculum bar over a symbol multiplies it by 1,000, reaching 3,999,999.
- 2026 is MMXXVI — M (1000) + M (1000) + X (10) + X (10) + V (5) + I (1) — and the breakdown chips show each symbol’s value adding up to 2026.
- Strict notation writes 4 as IV, never IIII — the subtractive pair replaces four repetitions, and this converter rejects IIII, VV or IC with a clear error.
Anatomy of a numeral
Seven symbols and six subtractive pairs build every Roman numeral from 1 to 3,999 — and a vinculum bar over a symbol multiplies it by 1,000, reaching 3,999,999.
Example: MMXXVI = M(1000) + M(1000) + X(10) + X(10) + V(5) + I(1) = 2026. Try it above — the breakdown chips show this for any conversion.
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How to convert Roman numerals
Three steps, instant answers.
Number to Roman, Roman back to a number, a date — or a whole list at once in Batch mode.
Any whole number 1–3,999,999, numerals like MMXXVI, or a date — in Batch, one value per line: numbers, numerals and dates can be mixed.
The result, plus what every symbol is worth.
⚙️How Roman numerals are built
Roman numerals combine seven symbols — I, V, X, L, C, D, M — largest to smallest. When a smaller symbol sits before a larger one, it subtracts: IV is 4, not 6. Only six such subtractive pairs exist (IV, IX, XL, XC, CD, CM), and strict form allows each pair exactly where the place value demands it.
Worked example: 2026 → 1000 + 1000 + 10 + 10 + 5 + 1 = MMXXVI. And MCMXCIV → 1000 + 900 + 90 + 4 = 1994. The converter validates strictly, so IIII, VV or IC are rejected with a clear error. Results above 3,999 carry the vinculum bar over the thousands group — and you can paste them straight back into the Roman → Number tab to check them.
Instead of repeating a symbol four times, Romans put the “one” of each place before its “five” or “ten”: IV (5−1) for 4, IX (10−1) for 9, XL (50−10) for 40, XC (100−10) for 90, CD (500−100) for 400, CM (1000−100) for 900. These are the only six legal subtractive pairs.
That is why IIII is invalid in strict notation — 4 must be IV. Likewise VV, LL and DD are never used (5, 50 and 500 already have their own symbols), and IC is wrong because I may only subtract from V and X. This converter enforces all of it.
Standard Roman notation has no symbol bigger than M (1,000), and strict form never repeats a symbol more than three times — so the largest writable value is MMMCMXCIX = 3,999. There is also no zero and no place value, which is why Romans did their serious arithmetic on counting boards, not in numerals.
Later writers extended the system with a vinculum (a bar over a numeral multiplying it by 1,000), but that is a medieval addition, not classical practice. For everyday use — clock faces, book chapters, movie sequels, outlines — 1 to 3,999 covers everything.
Frequently asked questions
How do I write 2026 in Roman numerals?
MMXXVI — M (1000) + M (1000) + X (10) + X (10) + V (5) + I (1). Type 2026 above and the breakdown chips show each symbol’s value adding up to 2026.
What is the largest Roman numeral?
3,999,999 in this converter. Standard notation alone stops at 3,999 = MMMCMXCIX (three Ms, CM, XC and IX), because no symbol exceeds M and none repeats more than three times — past that, the converter adds a vinculum bar over the thousands group, multiplying it by 1,000.
Why is IIII not a valid Roman numeral?
Strict Roman notation writes 4 as IV, never IIII — the subtractive pair replaces four repetitions. Clock faces famously break this rule and use IIII for visual symmetry, but that is a design tradition, not correct notation. This converter rejects IIII and suggests IV instead.
How do I read MCMXCIV?
Split it into tokens: M (1000) + CM (900) + XC (90) + IV (4) = 1994. Paste it into the converter to see the same breakdown as chips.
Did the Romans have a zero?
No. Roman numerals have no symbol for zero and no place value — the system was designed for recording counts and dates, not for written arithmetic. That is one reason the converter’s range starts at 1.
Can I convert numbers above 3,999?
Yes — with the historical vinculum: a bar over a symbol multiplies it by 1,000, so 4,999 is written with an overlined IV followed by CMXCIX. This converter applies the bar automatically for numbers from 4,000 up to 3,999,999.
How do I convert a full date to Roman numerals?
Part by part: the day, the month, and the year each become their own Roman numeral, in the order stated. The converter Date to Roman mode converts a calendar date this way, and its Roman Date mode reads a Roman date back into a numeric date in the order given, month, day, year. State the order explicitly, because the numerals themselves carry no order information.
Why did the converter reject my numeral?
Work the routine in order: check character identity (no digits, no stray punctuation), then repetition (no 1-symbol four times, no 5-symbol twice), then subtraction (only the six pairs IV, IX, XL, XC, CD, CM, and at most one per place), then place value (split the numeral and sum the breakdown). If the intended number is known, regenerate the numeral from it: the regenerated form is the correct form.
Can I convert a list of numbers at once?
Yes, with Batch mode: one value per line, where each value may be a number, a Roman numeral, or a date. Each line converts independently, and converting the results back round-trips the list for checking. Keep one value per line with no extra punctuation, and read per-line errors rather than skipping past them.
Roman numerals 1 to 100
The full chart — every number from 1 to 100 in strict Roman form. Read across each row of ten.
| Roman numerals 1–100 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| 1 = I | 2 = II | 3 = III | 4 = IV | 5 = V | 6 = VI | 7 = VII | 8 = VIII | 9 = IX | 10 = X |
| 11 = XI | 12 = XII | 13 = XIII | 14 = XIV | 15 = XV | 16 = XVI | 17 = XVII | 18 = XVIII | 19 = XIX | 20 = XX |
| 21 = XXI | 22 = XXII | 23 = XXIII | 24 = XXIV | 25 = XXV | 26 = XXVI | 27 = XXVII | 28 = XXVIII | 29 = XXIX | 30 = XXX |
| 31 = XXXI | 32 = XXXII | 33 = XXXIII | 34 = XXXIV | 35 = XXXV | 36 = XXXVI | 37 = XXXVII | 38 = XXXVIII | 39 = XXXIX | 40 = XL |
| 41 = XLI | 42 = XLII | 43 = XLIII | 44 = XLIV | 45 = XLV | 46 = XLVI | 47 = XLVII | 48 = XLVIII | 49 = XLIX | 50 = L |
| 51 = LI | 52 = LII | 53 = LIII | 54 = LIV | 55 = LV | 56 = LVI | 57 = LVII | 58 = LVIII | 59 = LIX | 60 = LX |
| 61 = LXI | 62 = LXII | 63 = LXIII | 64 = LXIV | 65 = LXV | 66 = LXVI | 67 = LXVII | 68 = LXVIII | 69 = LXIX | 70 = LXX |
| 71 = LXXI | 72 = LXXII | 73 = LXXIII | 74 = LXXIV | 75 = LXXV | 76 = LXXVI | 77 = LXXVII | 78 = LXXVIII | 79 = LXXIX | 80 = LXXX |
| 81 = LXXXI | 82 = LXXXII | 83 = LXXXIII | 84 = LXXXIV | 85 = LXXXV | 86 = LXXXVI | 87 = LXXXVII | 88 = LXXXVIII | 89 = LXXXIX | 90 = XC |
| 91 = XCI | 92 = XCII | 93 = XCIII | 94 = XCIV | 95 = XCV | 96 = XCVI | 97 = XCVII | 98 = XCVIII | 99 = XCIX | 100 = C |
Strict form throughout: 4 is IV (never IIII) and 99 is XCIX — the six subtractive pairs do the work. The converter above holds every value to the same standard.
The apostrophus: Rome’s first big numbers
Before D and M existed, a backwards C did the heavy lifting.
Long before the vinculum, Romans wrote big values with the apostrophus — a backwards C (Ɔ). One apostrophus after an I made IƆ = 500; closing it with a C in front made CIƆ = 1,000. Each extra Ɔ multiplied the value by ten, and matching Cs were added on the left at the ten-thousands and beyond: IƆƆ is 5,000, CCIƆƆ is 10,000, and three pairs reach CCCIƆƆƆ = 100,000. The shapes explain two modern letters — IƆ was rounded into D, and CIƆ into M. The system survives in Unicode as the single characters ↀ, ↁ, ↂ, ↇ and ↈ, and it still turns up in old inscriptions and manuscripts. This converter uses the later vinculum past 3,999 instead — but if you meet an apostrophus numeral in the wild, this table is how you read it.
| Apostrophus form | Value | What it became |
|---|---|---|
| IƆ | 500 | D |
| CIƆ | 1,000 | M — also written ↀ |
| IƆƆ | 5,000 | ↁ |
| CCIƆƆ | 10,000 | ↂ |
| IƆƆƆ | 50,000 | ↇ |
| CCCIƆƆƆ | 100,000 | ↈ |
The apostrophus forms are historical notation, shown for reference — inscriptions, manuscripts and old printed books are where you will meet them.
A year in Roman numerals
Cornerstones, film credits and keepsakes still carve the year in Roman numerals. Type a year and take it in three styles.
Lowercase is the style book front matter uses for page numbers; letter-spaced is the engraver’s cut. Years past 3,999 pick up the vinculum bar automatically.
Years, dates, and big numbers: and the mistakes that get rejected
The three places Roman numerals actually get used, plus the fixing routine.
Years convert by place value, and the century prefix does most of the work: every year from 1900 to 1999 begins with MCM (1,000 plus 900), and every year from 2000 begins with MM. So 1994 is MCMXCIV (1,000 plus 900 plus 90 plus 4), 2026 is MMXXVI, and 2030 is MMXXX. If a year conversion contains a 4 or a 9 but no subtractive pair, something has gone wrong, because 4 and 9 at any place require IV, IX, XL, XC, CD, or CM.
Dates convert part by part: day, month, and year each become their own numeral, in the order stated. Past 3,999, the vinculum bar multiplies a symbol by 1,000, so 4,999 is written with an overlined IV followed by CMXCIX, and this converter applies the bar automatically up to 3,999,999. A whole list converts at once in Batch mode, one value per line, and converting the results back round-trips the list for checking.
Rejections follow a short list. IIII fails repetition (4 is IV). VV, LL, and DD fail because 5-symbols never repeat. IC, IL, and XM fail because a 1-symbol subtracts only from the next two symbols above it. XXL fails double subtraction. Strings like V11 fail character identity, because they mix Arabic digits with Roman letters: the intended numeral is usually VII (7). The guides below work each territory in full.
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