Choose the direction
Start with an ASCII decimal integer or the letters I, V, X, L, C, D and M.
Private bidirectional Roman numeral converter
A canonical answer with the arithmetic visible
RomanClear converts in either direction under one modern profile. It rejects ambiguous-looking noncanonical strings, offers the deterministic canonical spelling and shows components plus a round-trip check.
1–3,999 · canonical modern profile · local only
Three explicit steps
Enter, convert, inspect
Convert under one profile
The supported interval is exactly 1 through 3,999; zero and overline notation are excluded.
Inspect components and round trip
Noncanonical Roman input is not silently accepted: the interpreted value and canonical suggestion remain visible.
Ordinary notation tasks
Useful for learning, editing and checking labels
- Check a chapter or volume label.
- Understand subtractive pairs such as IV and XC.
- Normalize a noncanonical spelling before editing.
- Show how a year decomposes into Roman components.
One value · no upload
Convert and inspect the canonical form
Enter a decimal integer or Roman string, see the canonical result and its components, then confirm the round trip locally.