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Roman Numeral Converter — Number ↔ Roman

Two-way Roman numeral converter (1–3999) with full validation. Client-side.

Free No signup Client-side Privacy friendly Updated

Number → Roman

Roman → Number

How to use

  1. 1 Type a number (1–3999) to get its Roman numeral.
  2. 2 Or type a Roman numeral to get the number.
  3. 3 Invalid numerals (like IIII or VX) are rejected.

Why use this tool

  • Two-way conversion with full validation of Roman numeral rules.
  • Covers the standard range 1 to 3999 (I to MMMCMXCIX).
  • Runs entirely in your browser.

Frequently asked questions

What are the Roman numeral symbols?

I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000. Smaller values before larger ones are subtracted (IV = 4, IX = 9).

Why is the maximum 3999?

Standard Roman numerals only go up to 3999 (MMMCMXCIX); larger numbers historically used a bar (vinculum) for ×1000, which is rarely used today.

Why is IIII invalid?

A symbol may repeat at most three times; 4 is written IV (subtractive notation), not IIII.

Is there a zero in Roman numerals?

No — the Roman system has no symbol for zero.

What is Roman Numeral Converter?

A Roman numeral converter translates between Arabic numbers and Roman numerals (I, V, X, L, C, D, M), using subtractive notation and validating the standard 1–3999 range.

Features

Both directions

Number → Roman and Roman → number, validated against standard notation.

Standard subtractive form

Produces canonical numerals (e.g. 4 = IV, 9 = IX) within the classic 1–3999 range.

Free & private

Runs on your device — nothing is uploaded.

Example

Input

2026

Output

MMXXVI

Common use cases

  1. 1

    Read clock & copyright dates

    Decode Roman numerals on clocks, film credits, and monuments.

  2. 2

    Number chapters & sections

    Convert outline or chapter numbers to Roman numerals.

  3. 3

    Learn the notation

    See how a number breaks into M/D/C/L/X/V/I with subtractive pairs.

Summary

Zerethon's Roman numeral converter translates between Arabic integers (1–3999) and Roman numerals in your browser, in both directions. It uses standard subtractive notation (IV, IX, XL, XC, CD, CM). Everything runs client-side — nothing is uploaded.

Category
Math
Pricing
Free
Privacy
Browser-based
Signup
Not required

References

Privacy

Your data never leaves your browser unless explicitly stated. Roman Numeral Converter runs entirely client-side — no server upload, no logging, no tracking of your input.

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