What are Roman numerals?
Roman numerals write numbers with seven letters. There is no zero and no place value: a letter is worth the same wherever it is, and the values are added up, except for six pairs where a smaller letter in front means take it away.
| Roman numeral | Value |
|---|---|
| I | 1 |
| V | 5 |
| X | 10 |
| L | 50 |
| C | 100 |
| D | 500 |
| M | 1,000 |
The only take-away pairs are IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900). Up to three of the same letter may sit together, so 3 is III but 4 is IV, not IIII.
How to convert numbers to Roman numerals
Here it is with your numbers:
- Thousands: 2 is 2,000, written MM.
- Hundreds: 0 means no symbols.
- Tens: 2 is 20, written XX.
- Ones: 6 is 6, written VI.
It means 2,026 is written MMXXVI.
Going the other way works the same: split the numeral into its thousands, hundreds, tens and ones, read each part from the chart below, and add them. If a numeral isn't written the standard way, like IIII or IC, the converter says so and shows the standard form.
Roman numerals chart
Every Roman numeral from 1 to 3,999 is made from these pieces, one from each column. The pieces of your answer are highlighted.
| Ones | Tens | Hundreds | Thousands |
|---|---|---|---|
| 1 I | 10 X | 100 C | 1,000 M |
| 2 II | 20 XX | 200 CC | 2,000 MM |
| 3 III | 30 XXX | 300 CCC | 3,000 MMM |
| 4 IV | 40 XL | 400 CD | — |
| 5 V | 50 L | 500 D | — |
| 6 VI | 60 LX | 600 DC | — |
| 7 VII | 70 LXX | 700 DCC | — |
| 8 VIII | 80 LXXX | 800 DCCC | — |
| 9 IX | 90 XC | 900 CM | — |
Roman numerals above 3,999
A bar over a letter multiplies it by 1,000, so V̅ is 5,000 and M̅ is 1,000,000. That goes up to 3,999,999, M̅M̅M̅C̅M̅X̅C̅I̅X̅CMXCIX. Plain M is still used for one to three thousand, so 8,000 is V̅MMM. To type a bar here, put an underscore before the letter.
| With a bar | Value | Type |
|---|---|---|
| I̅ | 1,000 | _I |
| V̅ | 5,000 | _V |
| X̅ | 10,000 | _X |
| L̅ | 50,000 | _L |
| C̅ | 100,000 | _C |
| D̅ | 500,000 | _D |
| M̅ | 1,000,000 | _M |
Source Britannica · Roman numerals: a bar (vinculum) over a numeral multiplies it by 1,000 ↗
Roman numerals examples
| Number | Roman numeral |
|---|---|
| 38 | XXXVIII |
| 94 | XCIV |
| 846 | DCCCXLVI |
| 1,984 | MCMLXXXIV |
| 2,948 | MMCMXLVIII |
| 3,999 | MMMCMXCIX |
| 4,000 | I̅V̅ |
| 1,000,000 | M̅ |
FAQs
How do I figure out my Roman numerals?
Split the number into thousands, hundreds, tens and ones, write each part with its symbols, and put them together, largest first. 2026 is 2,000 + 20 + 6, which is MM + XX + VI, so MMXXVI.
Why is 3999 the highest Roman numeral?
With the standard rules, a symbol can be repeated at most three times in a row and the largest symbol is M (1,000). So the biggest number they can write is 3,999, MMMCMXCIX. Bigger numbers need a bar over the letters, explained above. There is also no symbol for zero.
What number is XLV?
XLV is 45. XL is 40 (X before L means 10 less than 50) and V is 5.
What are the 7 rules of Roman numerals?
OpenStax lists seven: bigger values come first; up to three of a symbol may be grouped (III, XXX, CC); a larger value followed by a smaller one means add (VII, LV); I may only come before V or X (IV, IX); X only before L or C (XL, XC); C only before D or M (CD, CM); and when a symbol is repeated and also used to take away, the taking away comes last (XXIX for 29).
What does 666 look like in Roman numerals?
666 is DCLXVI: DC (600) + LX (60) + VI (6). It uses each of D, C, L, X, V and I once, from largest to smallest.
Why are Roman numerals no longer used?
They still are, for years on buildings, the year a movie was made and Super Bowl numbers. For counting and arithmetic, ordinary numbers took over: Roman numerals have no zero and no place value.
Sources
- OpenStax Contemporary Mathematics: 4.2 Early Numeration Systems: Roman numerals (Table 4.3 and the rules)
- Britannica: Roman numerals: a bar (vinculum) over a numeral multiplies it by 1,000