A small instrument for an old notation
Numerals,
translated.
Type a number on either side. The other answers immediately, with the same ceremony Romans gave to inscription.
i.
Type
Enter a value in either field. Conversion happens as you type.
ii.
Validate
Invalid Roman numerals (like IIII or IC) are rejected with a quiet note.
iii.
Copy
Press Enter to copy the result of the focused field to your clipboard.