Roman Numeral Converter

Numbers to Roman numerals and back — with the additive breakdown shown.

MCMLXXXIVresult

Breakdown: M + CM + LXXX + IV

1000 + 900 + 80 + 4 = 1984

How to convert Roman numerals

  1. Pick a direction. "Number → Roman" turns 1–3999 into numerals; "Roman → Number" decodes a numeral like MCMLXXXIV.
  2. Enter your value and press Convert. The result appears instantly, with the additive breakdown underneath.
  3. Read the breakdown. 1984 = M + CM + LXXX + IV, i.e. 1000 + 900 + 80 + 4 — each chunk is one place value.
  4. Watch the rules. I, X, C, M may repeat up to three times; V, L, D never repeat; only IV, IX, XL, XC, CD, CM subtract — so IIII, VV, and IL are rejected.

Frequently asked questions

Why is 4 written as IV and not IIII?

The Romans used subtractive notation: when a smaller symbol comes before a larger one, you subtract it. So IV means 5 − 1 = 4, which is shorter than IIII. The same trick gives IX (9), XL (40), XC (90), CD (400), and CM (900).

What is the largest Roman numeral?

In the standard system it is 3999, written MMMCMXCIX. Larger values need the vinculum — a bar drawn over a numeral multiplies it by 1,000, so V with a bar means 5,000.

Is there a Roman numeral for zero?

No. The Roman system had no symbol for zero and no negative numbers — it was built for counting things, so 1 (I) is the smallest value it can write.

How do you read a Roman numeral?

Read the symbols left to right and add them up, but subtract when a smaller symbol sits before a larger one: in MCMLXXXIV, CM is 900 (100 before 1000) and IV is 4 (1 before 5), giving 1000 + 900 + 80 + 4 = 1984.

What does the breakdown like M + CM + LXXX + IV mean?

It splits the numeral into its place-value chunks so you can check the total: M is 1000, CM is 900, LXXX is 80, and IV is 4, and 1000 + 900 + 80 + 4 = 1984.

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