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Convert Roman Numerals Both Ways

Turn any number into Roman numerals — or decode Roman numerals back into numbers — instantly.

Enter a number (1 – 3,999,999)

Numbers above 3,999 use the overline style: V̅ = 5,000, X̅ = 10,000, M̅ = 1,000,000.

Result

Input	Converted

Roman numeral reference chart

Numeral	Value	Numeral	Value
I	1	XC	90
IV	4	C	100
V	5	CD	400
IX	9	D	500
X	10	CM	900
XL	40	M	1,000
L	50	V̅	5,000
X̅	10,000	L̅	50,000
C̅	100,000	D̅	500,000
M̅	1,000,000	—	—

Overline numbers (V̅, X̅, …) multiply the letter’s value by 1,000. The converter reads and writes them automatically.

100% private

Conversion runs entirely in your browser. No data ever leaves your device.

No signup

Convert instantly — no accounts, no email, no waiting.

Free forever

Unlimited conversions, batch lists included. No locked features.

How to use the Roman numeral converter

1
Pick a direction
Choose “Number → Roman” to encode, “Roman → Number” to decode, or “Batch list” to convert many values at once.
2
Type your value
Enter any whole number from 1 to 3,999,999, or any Roman numeral. Try a quick example chip to see it work instantly.
3
Convert and copy
Hit Convert for the answer with a written breakdown, then use Copy result to paste it anywhere — essays, tattoo designs, watch faces.

Features

Both directions, one tool

Encode numbers to Roman numerals and decode Roman numerals back to numbers — switch with a single tab, no page reload.

Beyond 3,999 with overlines

Classic Roman stops at MMMCMXCIX, but this tool keeps going to 3,999,999 using the standard overline notation (V̅ = 5,000).

Strict validation

Invalid forms like IIII, VX, or IL are rejected with a plain-English explanation of what is wrong — you never get a silently wrong answer.

Batch conversion

Paste a whole list — numbers and numerals mixed, one per line — and get a tidy two-column table of every answer.

Written breakdown

Every conversion shows the math (e.g. 1994 = 1000 + 900 + 90 + 4), so you can learn the system instead of just copying answers.

Reference chart built in

The key numerals and their values live right on the page — a quick refresher for students, teachers, and tattoo planners.

Frequently asked questions

How do I convert a number to a Roman numeral?

Select “Number → Roman”, type any whole number from 1 to 3,999,999, and hit Convert. For example, 2026 becomes MMXXVI and 1994 becomes MCMXCIV. The tool also shows the breakdown of each part.

How do I convert a Roman numeral back to a number?

Select “Roman → Number” and type the numeral (lowercase is fine). MMXXIV decodes to 2024. The tool validates proper Roman form, so malformed input like IIII or VX gets an error instead of a guess.

Why is IIII not accepted? I have seen it on clock faces.

IIII does appear on some traditional clock dials, but it is not valid standard Roman numeral form — 4 is written IV. This tool enforces the standard rules (IV, IX, XL, XC, CD, CM), which is what schools and tests use.

What are the rules for valid Roman numerals?

I, X, C, and M can repeat up to three times; V, L, and D never repeat. Only I, X, and C can be used subtractively, and only before the next two larger values (IV, IX, XL, XC, CD, CM). V, L, and D are never used subtractively — so VX and LC are invalid.

Can Roman numerals go above 3,999?

Yes — with vinculum (overline) notation. A bar over a letter multiplies it by 1,000, so V̅ = 5,000, X̅ = 10,000, and M̅ = 1,000,000. This converter supports numbers up to 3,999,999 using that notation.

What number is MCMXCIV?

MCMXCIV = 1994 (M = 1000, CM = 900, XC = 90, IV = 4). Super Bowl XXVIII was played in 1994, which is why that numeral shows up in trivia so often.

Can I convert a whole list at once?

Yes — switch to the “Batch list” tab and paste one value per line. Numbers and Roman numerals can be mixed; each line is auto-detected and converted, and the results appear in a copy-friendly table.

Is there a Roman numeral for zero?

No — the Roman system had no zero and no negative numbers. This converter accepts whole numbers from 1 to 3,999,999.

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