Convert numbers to Roman numerals and vice versa.
The Roman Numeral Converter turns Arabic numbers into Roman numerals and reads Roman numerals back into standard numbers, following standard subtractive notation rules (like IV for 4 and IX for 9). Type a number into either field and get the conversion instantly — handy for decoding a copyright year at the end of a film, checking a tattoo idea, or working out a formal outline's chapter numbering.
Made for everyone. Typical uses:
Converting the year 1994 produces MCMXCIV (1000 + 900 + 90 + 4) — exactly the kind of copyright-year decoding this tool is built for. Paste the Roman numerals from the end of a film into the tool to get the production year back, or go the other direction to double-check a date before it's engraved somewhere permanent.
Standard Roman numerals only go up to 3,999 (MMMCMXCIX), since there's no standard symbol for 5,000 and beyond without adding overline notation, so it won't handle larger numbers. It also has no representation for zero or negative numbers, which the Roman numeral system itself doesn't support.
Accuracy: Conversions use well-known methods and are tested with real sample inputs. Check the output before you send or publish it.
Expert Tip
If you're decoding a copyright year from film credits, remember it's usually the production year rather than the theatrical release year — check both if the number you land on seems a year off from what you expected.
The Roman Numeral Converter works in both directions from one box. Type a number from 1 to 3999 and it returns the Roman numeral. Type Roman letters and it returns the number. Press Convert or Enter. The tool decides which direction you mean by what you typed: digits are treated as a number, letters as a numeral, and lower case letters are accepted.
These pairs were produced by the same algorithm the tool uses.
The seven symbols are I (1), V (5), X (10), L (50), C (100), D (500) and M (1000). Symbols are added from the largest to the smallest, so XVI is 10 + 5 + 1 = 16. A smaller symbol placed before a larger one is subtracted, but only in six pairs: IV, IX, XL, XC, CD and CM. A symbol may repeat at most three times in a row, and V, L and D never repeat, which is why 4 is IV and not IIII.
Reading a numeral is more than adding up letters. After the tool works out a value, it converts that value back into the standard numeral and compares it with what you typed. If they differ, the input is rejected. That catches IIII, VV and also less obvious mistakes: IC would add up to 99, but the correct form of 99 is XCIX, so IC is refused, and VX is refused for the same reason. You get a message saying the input is not a valid Roman numeral or a number from 1 to 3999. Mixed input such as 12abc is refused as well.
The most common place is the copyright year at the end of a film or television programme, which is usually the year of production rather than release. Others include sporting events, such as the Super Bowl, where 58 is LVIII, the names of monarchs and popes, the chapters and prefaces of books, outline numbering and building cornerstones. Clock faces often show 4 as IIII, a long-standing tradition. If you plan to engrave or tattoo a date, convert it forward and then paste the result back to confirm that it reads the same.
The standard system stops at 3999, because writing 4000 and more requires a bar over the letters to multiply by 1,000, which this tool does not support. There is no numeral for zero, no negative numbers and no fractions. Anything outside the range returns the message to enter a number between 1 and 3999. Everything is calculated in your browser.
To convert numbers between binary, octal, decimal and hexadecimal, use the Number Base Converter. For the number of days between two dates, such as the years carved on a monument, use the Days Between Dates calculator, and for measurements use the Unit Converter.
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