18 in Roman numerals
18 in Roman numerals
XVIII
18 is written XVIII in Roman numerals. That is 5 symbol groups added together, reading left to right from the largest value down.
How it breaks down
| Group | Value | Subtraction | Running total |
|---|---|---|---|
| X | 10 | — | 10 |
| V | 5 | — | 15 |
| I | 1 | — | 16 |
| I | 1 | — | 17 |
| I | 1 | — | 18 |
No subtraction needed
XVIII is purely additive — every symbol is simply added to the one before it, with no subtractive pairs like IV or IX. Numbers avoid subtraction when none of their digits is a 4 or a 9.
The symbols
| Symbol | Value | Used here |
|---|---|---|
| I | 1 | yes — 3× |
| V | 5 | yes — 1× |
| X | 10 | yes — 1× |
| L | 50 | no |
| C | 100 | no |
| D | 500 | no |
| M | 1,000 | no |
The same number, other ways
- In words
- Eighteen
- Roman numeral
- XVIII
- Symbol count
- 5 characters
- Binary
- 10010
- Hexadecimal
- 12
The numbers either side
| Number | Roman numeral |
|---|---|
| 16 | XVI |
| 17 | XVII |
| 18 | XVIII ← |
| 19 | XIX |
| 20 | XX |
Common questions
- What is 18 in Roman numerals?
- 18 is XVIII.
- What does XVIII mean?
- XVIII is the Roman numeral for 18 — 10 + 5 + 1 + 1 + 1.
- How do you write 18 in Roman numerals?
- Take the largest value that fits and repeat until nothing is left: X (10), then V (5), then I (1), then I (1), then I (1). That gives XVIII.
Related pages
Sources
- Calculated on this page — At One Place