Math · NUMORA
Roman Numerals Calculator
Convert 1–3999 both ways.
Open interactive calculatorHow to use
Standard subtractive notation.
Formula
Greedy lookup table
FAQ
Is this Roman Numerals calculator accurate?
The formula and assumptions are shown on the page, and the engine is covered by audit tests. Results are for reference — not financial or medical advice.
Do I need an account?
No. Calculations run in your browser. Recents can stay on this device.
What inputs do I need?
Standard subtractive notation.
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