Roman numerals
Convert numbers 1–3,999 and standard subtractive Roman numerals in either direction. See how each Roman symbol adds to or subtracts from the total.
Your inputs
Choose the conversion direction, then enter a number or Roman numerals. Results update as you edit.
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How it works
- ↔
- I = 1; V = 5; X = 10; L = 50; C = 100; D = 500; M = 1,000
- IV = 4; IX = 9; XL = 40; XC = 90; CD = 400; CM = 900
- Worked example: Read MMXXVI by adding two thousands, two tens, five and one. For IV, the smaller symbol before the larger one means subtraction. Use the same rules in reverse when converting a number.
- MMXXVI = 1,000 + 1,000 + 10 + 10 + 5 + 1 = 2,026; IV = 5 − 1 = 4.
Input and formula key
Your result
Complete the inputs to see your result.
Assumptions and limitations
Use standard subtractive Roman numerals for 1–3,999, such as IV, IX, or MMXXVI.
Sources
- Unicode — Number forms, Roman numeral symbols Sources reviewed: 2026-10-05
