Roman Numerals to Number
Be the first to rate this tool
Processed instantly and never stored — we keep no copy of your input.
Roman Numerals to Numbers in Depth
Read left to right, adding values — except when a smaller numeral precedes a larger one, then subtract: IV = 5 − 1 = 4, CM = 1000 − 100 = 900. MMXXVI decodes as 1000 + 1000 + 10 + 10 + 5 + 1 = 2026.
Validation
Proper numerals follow strict patterns — VV, LL, and DD are never valid, and subtractive pairs are limited (only I before V/X, X before L/C, C before D/M). Random letter strings like "XIVX" are not numerals at all; this converter flags malformed input rather than guessing.
Quick Checks
Clock faces, copyright dates in film credits (MCMLXXXIV = 1984), and old building cornerstones are the classic "what does that say?" moments this solves in seconds.