Writing 1 to 20 in Roman numerals
The numbers 1 to 20 run from I to XX. Every value below is paired with the wrong spelling people reach for, so you can see at a glance which 18 of these 20 numerals are the ones that actually catch people out.
How to use this table
The table above lists every number from 1 to 20 with the numeral you should write and, where one exists, the spelling people write instead. Symbols go largest first and add up, and a smaller symbol placed before a larger one subtracts. Almost every error in this range comes from ignoring that second rule and simply repeating a letter until the total is reached.
Once you know 1 to 10, the teens simply add X in front: XI is ten plus one, XIV is ten plus four (X + IV), XIX is ten plus nine (X + IX). The two subtractive pairs to watch are IV and IX.
Frequently asked questions
How do you write the numbers 1 to 20 in Roman numerals?
They run from I (1) to XX (20). For each one, take the largest Roman value that still fits, write its symbol, subtract it and repeat. The table above shows the finished numeral for every value, and each number links to its own step-by-step guide.
Which numbers between 1 and 20 are most often written wrongly?
18 of them have a well-known wrong form, and the table lists it next to the correct numeral. They are the values where a symbol would otherwise need a fourth repeat, so a subtractive pair takes over instead: 4 becomes IV rather than IIII and 9 becomes IX rather than VIIII.
How do you check a numeral in this range is right?
Read it back and add the groups up. If the total returns to the number you started from, the spelling is standard. The converter on this site round-trips every value and rejects non-standard forms, so anything it accepts is safe to use.
Other ranges
Last updated July 22, 2026. Reviewed for accuracy against the standard rules for Roman numerals. How we check accuracy.