Roman numerals use seven letters: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500 and M = 1,000. To read one, go from left to right and add the values, except when a smaller numeral stands before a larger one: then you subtract it. So XII is 10 + 1 + 1 = 12, while IX is 10 − 1 = 9, and MCMXCIV is 1,000 + 900 + 90 + 4 = 1994. This guide explains the rules, shows how to read and write years, gives a chart and covers the exceptions you will see on clocks and old buildings.
- Seven symbols: I, V, X, L, C, D, M. There is no zero and no symbol for fractions in everyday use.
- Read left to right and add. If a smaller value comes before a larger one, subtract it: IV = 4, XL = 40, CM = 900.
- Only six subtractive pairs are standard: IV, IX, XL, XC, CD and CM.
- I, X, C and M can repeat up to three times in a row; V, L and D never repeat.
- The standard system covers 1 to 3,999. Larger numbers used a bar (vinculum) meaning "times 1,000".
The seven symbols
| Symbol | Value | Memory aid |
|---|---|---|
| I | 1 | One finger or one tally mark |
| V | 5 | An open hand: the V between thumb and fingers |
| X | 10 | Two Vs joined point to point |
| L | 50 | Half of C (100) |
| C | 100 | Latin centum, as in century |
| D | 500 | Half of 1,000 |
| M | 1,000 | Latin mille, as in millennium |
The memory aids are just that. The symbols probably grew out of tally marks and older Etruscan number signs, and some only took the shape of letters later. The "C for centum" and "M for mille" links are handy all the same, because they really are the Latin words for 100 and 1,000.
The rules for reading Roman numerals
Rule 1: add from left to right
When symbols are written from the largest to the smallest, just add them: VIII = 5 + 1 + 1 + 1 = 8, LXX = 50 + 10 + 10 = 70, MDCLXVI = 1,000 + 500 + 100 + 50 + 10 + 5 + 1 = 1,666.
Rule 2: a smaller numeral before a larger one is subtracted
IV means "one before five", 4. XC is "ten before a hundred", 90. This subtractive notation keeps numbers short: 9 is IX instead of VIIII. There are only six standard pairs:
| Pair | Value | Instead of |
|---|---|---|
| IV | 4 | IIII |
| IX | 9 | VIIII |
| XL | 40 | XXXX |
| XC | 90 | LXXXX |
| CD | 400 | CCCC |
| CM | 900 | DCCCC |
The pattern behind them: you may only subtract a power of ten (I, X or C), and only from the next two larger symbols (I from V and X, X from L and C, C from D and M). So 99 is not IC but XCIX (90 + 9), 49 is not IL but XLIX (40 + 9), and 1999 is not MIM but MCMXCIX.
Rule 3: no more than three in a row
I, X, C and M can be repeated up to three times: III = 3, XXX = 30, CCC = 300, MMM = 3,000. A fourth repeat is replaced by a subtractive pair, which is why 4 is IV and 40 is XL. V, L and D are never repeated, because two of them make the next symbol: VV would just be X.
Rule 4: V, L and D are never subtracted
VX for 5 or LC for 50 are not valid: the plain symbols V and L already mean those values.
How to read any Roman numeral step by step
- Split the numeral into groups: single symbols and subtractive pairs (a smaller symbol directly before a larger one).
- Write the value of each group.
- Add the groups.
Example: MCMXCIV. Groups: M (1,000), CM (900), XC (90), IV (4). Total: 1,994.
Example: CDXLVIII. Groups: CD (400), XL (40), V (5), III (3). Total: 448.
Example: MMXXVI. Groups: MM (2,000), XX (20), VI (6). Total: 2,026.
A quick check: in a correctly written numeral the groups always get smaller from left to right. If a group is bigger than the one before it, the numeral is not standard (for example IXX or XCX).
How to write a number (or a year) in Roman numerals
Writing is easiest by place value: convert the thousands, hundreds, tens and units separately and put them side by side. This table contains every piece you need:
| Digit | Thousands | Hundreds | Tens | Units |
|---|---|---|---|---|
| 1 | M | C | X | I |
| 2 | MM | CC | XX | II |
| 3 | MMM | CCC | XXX | III |
| 4 | – | CD | XL | IV |
| 5 | – | D | L | V |
| 6 | – | DC | LX | VI |
| 7 | – | DCC | LXX | VII |
| 8 | – | DCCC | LXXX | VIII |
| 9 | – | CM | XC | IX |
Worked example: 2026. 2 thousands = MM, 0 hundreds = nothing, 2 tens = XX, 6 units = VI, so 2026 = MMXXVI.
Worked example: 1987. M + CM + LXXX + VII = MCMLXXXVII.
Worked example: 3,999, the largest standard numeral: MMM + CM + XC + IX = MMMCMXCIX.
Zeros are simply skipped, which is why the Romans did not need a zero symbol for writing numbers: 2005 is MMV and 1900 is MCM. The Roman numerals converter does this for any number from 1 to 3,999, shows the breakdown, and checks whether a numeral you type is written correctly.
Roman numerals chart
| Number | Roman | Number | Roman | Number | Roman |
|---|---|---|---|---|---|
| 1 | I | 11 | XI | 30 | XXX |
| 2 | II | 12 | XII | 40 | XL |
| 3 | III | 13 | XIII | 50 | L |
| 4 | IV | 14 | XIV | 60 | LX |
| 5 | V | 15 | XV | 70 | LXX |
| 6 | VI | 16 | XVI | 80 | LXXX |
| 7 | VII | 17 | XVII | 90 | XC |
| 8 | VIII | 18 | XVIII | 100 | C |
| 9 | IX | 19 | XIX | 500 | D |
| 10 | X | 20 | XX | 1,000 | M |
The converter page has the full chart from 1 to 100, key values up to 3,999 and recent years.
Why some clocks show IIII instead of IV
Look at a clock face with Roman numerals and you will often see IIII for four, even though IV is the standard form today. Clockmakers have used IIII for centuries, and there is no single proven reason. Common explanations are visual balance (IIII mirrors the heavy VIII on the other side of the dial), tradition, and the fact that the Romans themselves often wrote IIII: the strict subtractive rules taught in schools became the norm long after the Roman Empire. Some famous clocks, such as the Great Clock of Westminster (Big Ben), use IV, so both forms are accepted on dials. Outside clock faces, use IV.
Numbers above 3,999: the vinculum
Because no symbol may repeat more than three times, the standard system stops at MMMCMXCIX (3,999). For larger values, Roman and medieval writers used extensions. The best known is the vinculum, a line drawn over a numeral that multiplies it by 1,000: V̅ = 5,000, X̅ = 10,000, M̅ = 1,000,000. So 4,000 can be written I̅V̅ and 12,500 as X̅MMD. These forms were never fully standardised, so today they are mostly a curiosity; very large numbers are simply written in ordinary digits.
What about zero and fractions?
There is no Roman numeral for zero. The Romans had words for "nothing", and medieval scholars computing the date of Easter sometimes wrote nulla ("none"), or just N, in their tables, but it was never a digit in the way 0 is in our place-value system. Fractions existed in Roman measurement, based on twelfths (the uncia), with their own signs, but they are not part of the numerals people use today.
Where you see Roman numerals today
- Clocks and watches, often with IIII for four.
- Monarchs and popes: Charles III, Louis XIV, Elizabeth II, Pope Benedict XVI.
- Film and TV credits: the copyright year, for example MMXXVI for 2026.
- Sporting events: the Super Bowl is numbered in Roman numerals (Super Bowl 50 in 2016 was a well-known exception that used ordinary digits).
- Books and documents: chapter and volume numbers, and lower-case numerals (i, ii, iii, iv) for front-matter page numbers.
- Buildings and monuments: foundation years on facades and gravestones, and the entrance numbers still visible over the arches of the Colosseum in Rome.
- Tattoos and engravings: birth or wedding dates such as XV.X.MMXXVI (15.10.2026). Always double-check these with a converter before they become permanent.
Common mistakes to avoid
- Subtracting the wrong symbol: 99 is XCIX, not IC; 45 is XLV, not VL; 1990 is MCMXC, not MXM.
- Four in a row: 40 is XL, not XXXX (outside clock faces).
- Mixing up D and M, or L and C, when reading quickly: D is 500, M is 1,000; L is 50, C is 100.
- Forgetting that order matters: XI is 11 but IX is 9.
Working with dates? The date calculator counts days between dates and finds the weekday, and the age calculator gives an exact age from a birth date. More quick helpers are in everyday tools.
Frequently asked questions
How do you read Roman numerals?
Add the values from left to right, but subtract any smaller numeral that comes directly before a larger one. For example XIV is 10 + (5 − 1) = 14, and MCMXCIV is 1,000 + 900 + 90 + 4 = 1,994.
What is 4 in Roman numerals?
IV (one before five). Clock faces often use IIII instead, a long-standing clockmakers' tradition, but IV is the standard form everywhere else.
What is 2026 in Roman numerals?
MMXXVI: MM for 2,000, XX for 20 and VI for 6.
Why is 99 not written IC?
Only I, X and C may be subtracted, and only from the next two larger symbols. I can be subtracted from V and X but not from C, so 99 is written as 90 + 9 = XCIX.
What is the largest number in Roman numerals?
With the standard rules it is 3,999 (MMMCMXCIX). Larger numbers used a bar over the numerals, called a vinculum, to multiply by 1,000, but that extension was never standardised.
Is there a zero in Roman numerals?
No. The system has no digit for zero because it does not use place value; positions with nothing in them are simply left out, as in MMV for 2005.