Roman Numerals Cheatsheet
A quick reference for Roman numeral symbols, values, subtractive notation rules, and conversion examples for numbers 1–3999.
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Symbol Values
| Symbol | Value |
|---|---|
I | 1 |
V | 5 |
X | 10 |
L | 50 |
C | 100 |
D | 500 |
M | 1,000 |
Subtractive Notation Rules
When a smaller symbol appears before a larger one, it is subtracted. Only six subtractive combinations are valid.
| Combination | Value | Notes |
|---|---|---|
IV | 4 | I before V — subtracts 1 from 5 |
IX | 9 | I before X — subtracts 1 from 10 |
XL | 40 | X before L — subtracts 10 from 50 |
XC | 90 | X before C — subtracts 10 from 100 |
CD | 400 | C before D — subtracts 100 from 500 |
CM | 900 | C before M — subtracts 100 from 1000 |
Additive Rules
Symbols are generally written largest to smallest, left to right, and added together.
| Rule | Example |
|---|---|
Repeat a symbol up to 3 times | III = 3, XXX = 30, CCC = 300, MMM = 3000 |
V, L, D are never repeated | VV is invalid — use X instead |
Write largest values first | XVII = 10 + 5 + 1 + 1 = 17 |
Max value without a vinculum | 3,999 (MMMCMXCIX) |
Numbers 1–20
| Arabic | Roman |
|---|---|
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 |
Tens & Hundreds
| Arabic | Roman |
|---|---|
10 | X |
20 | XX |
30 | XXX |
40 | XL |
50 | L |
60 | LX |
70 | LXX |
80 | LXXX |
90 | XC |
100 | C |
200 | CC |
300 | CCC |
400 | CD |
500 | D |
600 | DC |
700 | DCC |
800 | DCCC |
900 | CM |
Thousands
| Arabic | Roman |
|---|---|
1,000 | M |
2,000 | MM |
3,000 | MMM |
3,999 | MMMCMXCIX |
Common Years
| Year | Roman |
|---|---|
1776 | MDCCLXXVI |
1900 | MCM |
1999 | MCMXCIX |
2000 | MM |
2001 | MMI |
2010 | MMX |
2020 | MMXX |
2024 | MMXXIV |
2025 | MMXXV |
Conversion Method
To convert an Arabic number to Roman numerals, repeatedly subtract the largest possible symbol value.
| Step | Remainder | Symbol Added |
|---|---|---|
2764 → subtract 1000 | 1764 | M |
1764 → subtract 1000 | 764 | M |
764 → subtract 500 | 264 | D |
264 → subtract 100 | 164 | C |
164 → subtract 100 | 64 | C |
64 → subtract 50 | 14 | L |
14 → subtract 10 | 4 | X |
4 → subtract 4 (IV) | 0 | IV |
Result | — | MMDCCLXIV |