English
How do Roman numerals work?
A Roman numeral converter works with just seven letters: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500 and M = 1,000. You read left to right and add the values, so XVI is 10 + 5 + 1 = 16. The one exception is subtraction: a smaller letter placed directly before a larger one is taken away, so IX is 10 − 1 = 9 and MCMXCIV is 1000 + 900 + 90 + 4 = 1994.
| Letter | I | V | X | L | C | D | M |
|---|---|---|---|---|---|---|---|
| Value | 1 | 5 | 10 | 50 | 100 | 500 | 1,000 |
What are the rules for writing them?
- I, X, C and M can repeat up to three times in a row (III = 3, XXX = 30). Four in a row is wrong: 4 is IV.
- V, L and D never repeat. Two Vs would be X, so VV is not used.
- Only I, X and C can be subtracted, and only from the next two letters up: I from V and X, X from L and C, C from D and M. That gives six pairs: IV, IX, XL, XC, CD, CM.
- Write the thousands first, then the hundreds, tens and ones, each as its own block. 1,945 is M, CM, XL, V.
The tool above checks every numeral against these rules. Type IL and it tells you that I can only sit in front of V or X, so 49 is XLIX. Type IIX and it explains why 8 is VIII.
Is IIII a valid Roman numeral?
By the standard rule, no. You will still see IIII on many clock faces, and some old inscriptions used it for 4 as well. It is a tradition and not an error on the clock, but in anything you write, use IV.
Roman numerals 1 to 100
| Number | Roman | Number | Roman |
|---|---|---|---|
| 1 | I | 10 | X |
| 4 | IV | 20 | XX |
| 5 | V | 40 | XL |
| 8 | VIII | 50 | L |
| 9 | IX | 90 | XC |
| 14 | XIV | 99 | XCIX |
| 19 | XIX | 100 | C |
For a full table, use the list section of the tool: pick a range such as 1 to 100 and download it as a CSV for a spreadsheet.
What are the years 2000 to 2030 in Roman numerals?
Start with MM for 2000 and add the last two digits: 2024 is MMXXIV, 2025 is MMXXV, 2026 is MMXXVI and 2030 is MMXXX. Copyright years on films and old buildings use the same method, and 1999 is MCMXCIX (M, CM, XC, IX). A common slip is writing 1999 as MIM or IMM, but I can only be subtracted from V and X.
How do you write a date in Roman numerals?
Convert each part by itself and join them with dots, dashes or slashes. 17 August 1945 becomes XVII.VIII.MCMXLV in day, month, year order. Month numbers are the usual 1 to 12, so December is XII. Many documents keep the day in ordinary digits and only put the month in Roman numerals, which avoids confusion between orders. The date section handles any order and separator you need.
What comes after 3999?
Classic Roman numerals stop at MMMCMXCIX (3,999) because M cannot repeat a fourth time. The older fix is a bar over the letters, which multiplies them by 1,000: V with a bar is 5,000, X with a bar is 10,000 and M with a bar is 1,000,000. The largest value this tool reaches is 3,999,999. If your font does not draw the bar, switch the style to brackets, where (V) means 5,000. Text pasted into a chat may lose the bar, so the bracket form is the safer choice there.
XLV = 45 → 45 × 1,000 = 45,000, then DCLXXVIII = 678
There is no zero
Roman numerals have no symbol for zero and no negative numbers, so 0 and anything below it are rejected. Fractions existed in a separate system based on twelfths, which this tool does not cover.
Frequently asked questions
What is 2026 in Roman numerals?
2026 is MMXXVI: MM for 2000, XX for 20 and VI for 6. Type any year in the number box to see it with its breakdown.
How do you write 4 and 9 in Roman numerals?
4 is IV (one before five) and 9 is IX (one before ten). The same idea gives 40 as XL, 90 as XC, 400 as CD and 900 as CM.
Is IIII a valid Roman numeral?
In strict standard form no: 4 is written IV. IIII does show up on clock faces and some old inscriptions, so you may see it, but the usual rule allows at most three of I, X, C or M in a row.
What is the biggest Roman numeral?
In the classic system it is MMMCMXCIX, which is 3,999, because there is no letter above M (1,000) and you cannot repeat it more than three times. A bar over a letter multiplies it by 1,000, which stretches the range to 3,999,999.
Is there a zero or a negative number in Roman numerals?
No. The system has no zero and no negatives. Medieval writers used the word nulla for nothing, but there is no symbol for it.
How do you write a date in Roman numerals?
Convert the day, month and year separately and join them with dots or dashes. 17 August 1945 is XVII.VIII.MCMXLV. Use the date section of the tool and pick your separator and order.
How do you read a Roman numeral like MCMXCIV?
Read left to right and add the letters, except when a smaller letter sits in front of a larger one, which subtracts. M + CM + XC + IV = 1000 + 900 + 90 + 4 = 1994.
How do I write numbers over 3999 in Roman numerals?
Put a bar over the letters to multiply them by 1,000: V with a bar is 5,000 and M with a bar is 1,000,000. Tick the extension option above, or use brackets like (V) if your font does not show the bar.