Roman Numeral Converter — Number to Roman & Roman to Number
Free Roman numeral converter: numbers to Roman and Roman to numbers (1–3999), with a clickable 1–100 chart, clock and year tools — all in your browser.
Smart Two-Way Conversion
Auto-detects direction · number or Roman numeral (1 – 3999)
Clock Face · I – XII
The classic use case · hover for value, click to copy
Clock tradition uses IIII instead of IV for 4 — symmetrical, less crowding at that position, and the only place where "four in a row" survives.
Book Volume & Chapter Numbering
TOC, volumes, chapters, clauses — generate and copy in one go
Year & Ordinal Titles
Copyright years, dedication years, monarch-style ordinal titles
Reading ordinal titles: Elizabeth II = the second monarch of that name.
How to Type Roman Numerals? Click to Copy
Unicode Roman numeral characters · paste into any text
Uppercase Ⅰ–Ⅻ (from U+2160). Lowercase ⅰ–ⅻ cannot be typed in most IMEs — copy from here and lowercase it yourself; the universal approach is still typing the letters I V X L C D M.
Roman Numeral Chart (1 – 100)
Click any cell to copy
About this tool
Type 2026 and get MMXXVI. Paste MMXXVI and get 2026. This Roman numeral converter works in both directions with no mode to switch — it detects the direction for you — and adds the tools people actually need around it: a clickable Roman numeral chart for 1–100, a clock face (I–XII), book volume & chapter numbering, copyright-year conversion, and Unicode Roman numeral characters to copy. Everything runs locally in your browser; nothing you type is uploaded anywhere.
The three rules of Roman numerals
Roman numerals are built from seven letters — I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000 — combined under three rules:
- Same letter at most 3 times in a row. III = 3, XXX = 30, CCC = 300. Four in a row is never standard — 4 is IV, not IIII (clock dials are the one traditional exception).
- Subtraction uses exactly six pairs. A smaller letter placed before a larger one subtracts. Only these six combinations are valid:
| Pair | Value | Pair | Value |
|---|---|---|---|
| IV | 4 (5 − 1) | XL | 40 (50 − 10) |
| IX | 9 (10 − 1) | XC | 90 (100 − 10) |
| CD | 400 (500 − 100) | CM | 900 (1000 − 100) |
Anything else — IC for 99, XM for 990 — looks plausible but is invalid; 99 is XCIX and 990 is CMXC.
- V, L and D never repeat. They take no subtractive prefix and are never doubled: 10 is X, never VV; 1000 more than D is M, never DD.
The standard range is 1 – 3999: MMMCMXCIX is the largest number without an overline (the historical "times a thousand" mark, V̅ = 5000). Roman numerals also have no zero, no negatives and no fractions.
Converting a number to Roman numerals, step by step
The algorithm is greedy — always take the largest value that fits, then repeat on the remainder. For 2026:
- 2026 ≥ 1000 → MM, remainder 26
- 26 ≥ 10 → XX, remainder 6
- 6 ≥ 5 → V, remainder 1
- 1 ≥ 1 → I, remainder 0
Result: MMXXVI. A few more you will meet constantly: 4 = IV, 9 = IX, 40 = XL, 90 = XC, 400 = CD, 900 = CM, 1900 = MCM, 2024 = MMXXIV, 3999 = MMMCMXCIX. Type any number from 1 to 3999 into the converter above and it applies these steps instantly.
How to read Roman numerals
Scan left to right. If a letter is smaller than the one after it, subtract it; otherwise add it. For MMXXVI:
- M (1000) ≥ next M → +1000, +1000
- X (10) ≥ next X → +10, +10
- V (5) ≥ next I → +5
- I (1) is last → +1
Total: 2026. The only place you ever subtract is before one of the six pairs, which is why reading is mechanical once you know the table. The converter above also accepts non-standard input like IIII or Unicode clock characters (Ⅰ–Ⅻ): it evaluates the value first, then tells you the canonical writing.
Why clocks use IIII for 4
Look at any watch dial and the 4 position reads IIII, not IV. The tradition has practical roots: IIII balances VIII on the other side of the dial, four characters fill the wide arc at 4 o'clock more evenly than two, and early dial painters avoided IV because it was easy to confuse with VI at a glance. It is the only widely accepted place where "four in a row" survives. The clock card above renders a full I–XII dial — hover any numeral to see its value, click to copy.
Where you still see Roman numerals
- Books and academic writing — volume numbers (Volume I, Volume II), preface page numbers (i, ii, iii), chapter numbering in classic editions, and outline levels (I. → A. → 1. → a.)
- Film and television — sequel numbering (Rocky II, Star Wars: Episode IV) and end-credit copyright years (© MMXXVI)
- Monarchs and popes — ordinals distinguish same-named rulers: Elizabeth II, Louis XIV, Henry VIII, Pope Pius XII
- Sports — Super Bowl editions (LVII, LIX), Olympiad numbers
- Buildings and monuments — dedication years on cornerstones and plaques
- Watch faces — the I–XII dial described above
The year card in the tool converts any year 1–3999 and generates the © MMXXVI copyright line in one click, along with ready-made monarch-style ordinals you can copy.
Typing Roman numerals on a keyboard
Two practical answers. The universal one: Roman numerals are just the seven capital letters I V X L C D M — type them as ordinary letters in any editor. The special one: Unicode has dedicated characters Ⅰ Ⅱ Ⅲ … Ⅻ (starting at U+2160, plus lowercase ⅰ–ⅻ) used mainly on clock dials and in CJK text; most IMEs cannot produce them, so the card above gives you one-click copies for all twelve. Paste either form into the converter — both are recognized.
Need more than conversion? The date calculator handles day counting and date arithmetic, the case converter flips text between UPPER and lower case, and the simplified-traditional Chinese converter covers the two Chinese script systems — all in the same online tools collection, all running locally in your browser.
FAQ
How do you write 0 in Roman numerals?
You cannot — Roman numerals are a counting notation, not a complete number system. Use Arabic numerals wherever zero is needed.
How do you read Roman numerals?
Read the value they represent: MMXXVI reads "two thousand twenty-six". The letters (I V X L C D M) are abbreviations of Latin words and are not pronounced separately.
Why does typing IIII still give 4?
The tool evaluates the letters first, then checks the canonical form: IIII computes to 4, with a hint that the standard writing is IV. Clock dials commonly use IIII as a traditional exception.
Why does it stop at 3999?
In standard notation M repeats at most three times (MMM = 3000), so 3999 = MMMCMXCIX is the largest number representable without an overline.
Why do clocks use IIII for 4?
Watchmaking tradition: IIII balances VIII visually, the 4-o'clock position is less crowded, and early makers avoided confusion with engraved IV. It is the only widely accepted "four in a row" exception.
Why do books use Roman numerals?
Publishing tradition: prefaces use lowercase roman (i, ii, iii) to distinguish them from Arabic page numbers; multi-volume works number volumes in uppercase Roman (Volume I, Volume II), a convention that continues today.
Where do people still use Roman numerals?
Clocks and watches, book volumes and chapters, film sequels and end-credit years, Super Bowl editions (LVII), monarch and pope ordinals (Elizabeth II), building dedication years, and tattoos.