Roman Numerals Converter
Convert any number to Roman numerals — or Roman numerals back to a number. Includes colour-coded step-by-step breakdown, live Roman clock, full 1–100 reference and the rules explained. 2026 = MMXXVI.
ROMAN NUMERALS CONVERTER
Enter a number or Roman numerals
Accepts 1–3,999 or any valid Roman numerals
Quick examples
The 4 core rules
Symbols are added left to right
XIII = X + I + I + I = 10 + 1 + 1 + 1 = 13
A symbol repeats at most 3 times
III = 3 ✓ IIII = ✗ (use IV instead)
Smaller before larger = subtract
IV = 5 − 1 = 4 IX = 10 − 1 = 9 CM = 1000 − 100 = 900
Only I, X, C can be subtractive
I before V,X · X before L,C · C before D,M
Step-by-step solution
Live Roman numeral clock
Both clocks update together — observe the subtractive transitions
The 7 base symbols
| Symbol | Value | Latin Name |
|---|---|---|
| I | 1 | Unus |
| V | 5 | Quinque |
| X | 10 | Decem |
| L | 50 | Quinquaginta |
| C | 100 | Centum |
| D | 500 | Quingenti |
| M | 1,000 | Mille |
The 6 subtractive pairs
⏰ Clock curiosity
Most Roman numeral clock faces use IIII instead of IV for 4 o'clock. Clockmakers preferred visual symmetry (IIII balances VIII opposite), and it was standard practice in medieval timekeeping before modern subtractive rules solidified.
Roman Numerals Converter Explained
Core concepts, classroom applications, and plain-English explanations for all audiences.
You see Roman numerals more than you think
Clock faces (I through XII), film release years in closing credits (MMXXV = 2025), Super Bowl numbering (Super Bowl LIX), book prefaces (chapters i, ii, iii), and inscriptions on official buildings all use Roman numerals. They're not dead — they're on display in every city.
Worked example
"What year is MCMXCIX, and why is it written that way?"
M = 1000
CM = 900 (C before M: 1000 − 100)
XC = 90 (X before C: 100 − 10)
IX = 9 (I before X: 10 − 1)
Result: 1000 + 900 + 90 + 9 = 1999
MCMXCIX is one of the most complex common Roman numerals — often used on late-1990s film credits.
The key subtractive rule
- → Only I, X, C can be subtractive: I before V or X. X before L or C. C before D or M. Nothing else. VX, LC, DM are not valid.
- ✗ No symbol repeats more than 3 times: III = 3 is valid. IIII is not standard — use IV instead.
There is no zero in Roman numerals
This is why Roman mathematics stayed limited. Without zero, positional notation is impossible — you can't do long multiplication or division the way we do now. The Hindu-Arabic numeral system (what we use) changed everything.
Roman numerals 1–100
Click any cell to load it into the converter.
Roman numerals in everyday life
Super Bowl
The NFL has used Roman numerals since Super Bowl V (1971). Super Bowl LIX (59) is 2025. The tradition was briefly paused — Super Bowl 50 skipped Roman numerals to avoid calling it "L".
Royalty & Popes
Henry VIII, Elizabeth II, Louis XIV, Pope Francis (no numeral = first). Roman numerals distinguish monarchs with the same name — Henry VIII was the eighth English king named Henry.
Film & TV dates
End credits show the production year in Roman numerals — a tradition from when studios wanted to obscure how old a film was for reruns. © MMXXVI hides the year at a glance.
Buildings & monuments
Cornerstones, monuments and public buildings often use Roman numerals for foundation dates. The US Capitol cornerstone reads MDCCXCIII (1793).
Books & chapters
Prefaces, forewords and introductions are traditionally numbered with Roman numerals (i, ii, iii...) to distinguish them from the main text. Same with volume numbers.
Tattoos
Birth dates in Roman numerals are among the most popular tattoo designs. Converting 15/08/1990 gives XV · VIII · MCMXC — each section converted separately, not as one number.
What Roman numerals can't do
No zero
Romans had no concept of zero — which is why Arabic numerals (with zero) were so revolutionary for mathematics, commerce and eventually computing.
No fractions
Romans used a separate system (based on 12ths — "uncia") for fractions, not Roman numeral extensions. There's no way to write 2.5 in Roman numerals.
Max is 3,999
Standard Roman numerals top out at MMMCMXCIX (3,999). Larger numbers required a bar over a symbol (vinculum) to multiply by 1,000 — but this is rarely used today.