# Free online Roman numeral converter

> Roman numerals use seven letters to represent numbers. Enter any Arabic number (1–3999) or Roman numeral to convert between the two systems.

Convert between Arabic numbers and Roman numerals instantly. Supports numbers from 1 to 3999 with a full symbol breakdown.

**Interactive version:** https://onlinecalculator.me/math/roman-numeral/
**Category:** Math

## How to use

1. Type any **Arabic number** (1–3999) or **Roman numeral** in the input box.
2. Click **Convert**.
3. See the converted value and a breakdown of each symbol.

## Roman numeral rules

| Ones | Tens | Hundreds | Thousands |
|------|------|----------|-----------|
| I = 1 | X = 10 | C = 100 | M = 1000 |
| II = 2 | XX = 20 | CC = 200 | MM = 2000 |
| III = 3 | XXX = 30 | CCC = 300 | MMM = 3000 |
| IV = 4 | XL = 40 | CD = 400 | — |
| V = 5 | L = 50 | D = 500 | — |
| VI = 6 | LX = 60 | DC = 600 | — |
| VII = 7 | LXX = 70 | DCC = 700 | — |
| VIII = 8 | LXXX = 80 | DCCC = 800 | — |
| IX = 9 | XC = 90 | CM = 900 | — |

## Worked examples

| Arabic | Roman | Breakdown |
|--------|-------|-----------|
| 1776 | MDCCLXXVI | M + D + CC + L + XX + V + I |
| 1999 | MCMXCIX | M + CM + XC + IX |
| 2024 | MMXXIV | MM + XX + IV |
| 3999 | MMMCMXCIX | MMM + CM + XC + IX |

## Frequently asked questions

### What are the Roman numeral symbols?

The seven symbols are: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000. Larger numbers combine these using addition and subtraction.

### How does subtractive notation work?

When a smaller symbol precedes a larger one, it is subtracted. IV = 4 (5−1), IX = 9 (10−1), XL = 40 (50−10), XC = 90 (100−10), CD = 400 (500−100), CM = 900 (1000−100). Only these six combinations are standard.

### Why does Roman notation stop at 3999?

The standard system only allows three consecutive identical symbols (III, XXX, CCC, MMM). 4000 would require MMMM, which breaks this rule. Larger numbers require a different notation system.

### Is there a zero in Roman numerals?

No. The Romans had no symbol for zero — it was introduced to Europe from Arabic/Indian mathematics in the medieval period.

### What year is 2024 in Roman numerals?

2024 = MMXXIV. Breaking it down — MM = 2000, XX = 20, IV = 4.

## Sources

- [Roman numerals](https://en.wikipedia.org/wiki/Roman_numerals) — Wikipedia
- [Roman Numerals](https://mathworld.wolfram.com/RomanNumerals.html) — Wolfram MathWorld

## Related calculators

- [Prime factorization calculator](https://onlinecalculator.me/math/prime-factorization/) — Find all prime factors of a number.
- [Exponent calculator](https://onlinecalculator.me/math/exponent/) — Calculate any base raised to any power.
- [Week number calculator](https://onlinecalculator.me/date-time/week-number/) — Find the ISO or US week number for any date.
- [Factorial calculator](https://onlinecalculator.me/math/factorial/) — Calculate n! and combinatorial values.

---

Part of [onlinecalculator.me](https://onlinecalculator.me/) — free calculators that run entirely in your browser.
Machine-readable index: https://onlinecalculator.me/llms.txt