Roman Numerals 1-40

Need a number above 40? Use the converter.

The pattern

  • From 1 to 40 you only need 4 symbols: I (1), V (5), X (10), and L (50).
  • 9 of the 40 numbers use subtraction: every number with a 4 or a 9 in one of its places, such as 4 (IV), 9 (IX), and 40 (XL).
  • Each number is its ten followed by its unit, read from left to right: 37 (XXXVII) is XXX + VII, and 44 (XLIV) is XL + IV.
  • The longest is 38, XXXVIII, with 7 letters.
  • New compared with the 1–30 list: the symbol L (50) and XL for 40 (L − X).

Building blocks

Every number here is put together from these pieces, from the largest place to the smallest.

Building blocks
DigitUnitsTens
1I 1X 10
2II 2XX 20
3III 3XXX 30
4IV 4XL 40
5V 5—
6VI 6—
7VII 7—
8VIII 8—
9IX 9—

Common mistakes

Wrong: VIIII

Why isn't 9 written VIIII?

A symbol can repeat at most three times in a row. The correct form is IX: X − I.

Wrong: IIX

Why isn't 8 written IIX?

Only one smaller symbol can come before a larger one. The correct form is VIII: V + I + I + I.

How to remember them

The rules behind every row are explained in how Roman numerals work.

Try it

Five numbers from this list. Answer in your head, then open the answer.

  1. 1.How do you write 40?Show the answer

    XL

  2. 2.What number is XV?Show the answer

    15

  3. 3.How do you write 38?Show the answer

    XXXVIII

  4. 4.What number is XXVII?Show the answer

    27

  5. 5.How do you write 9?Show the answer

    IX

Common questions

Which numbers from 1 to 40 use subtraction?

9 of the 40: every number that has a 4 or a 9 in its units, tens or hundreds. The first ones are 4 (IV), 9 (IX), 14 (XIV), and 19 (XIX); the last one is 40 (XL).

What is the longest Roman numeral from 1 to 40?

XXXVIII (38), with 7 letters.

Why is 40 written XL and not XXXX?

XXXX would repeat X four times, and a symbol can repeat at most three times in a row. Putting X before L means L − X = 40.

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