Roman numeral converter
Type a number to get its Roman numeral, or type a Roman numeral to get the number. The answer is split by place value, the same way you would write it by hand.
Roman numeral
XLVIII
48 = 40 + 8
- 40 = XL
- 8 = VIII
The example (48) is filled in. Type any number or numeral to convert.
Roman numerals chart
The seven symbols, then 1 to 20 and the larger values you see most.
| I | V | X | L | C | D | M |
|---|---|---|---|---|---|---|
| 1 | 5 | 10 | 50 | 100 | 500 | 1,000 |
| Number | Roman numeral |
|---|---|
| 1 | I |
| 2 | II |
| 3 | III |
| 4 | IV |
| 5 | V |
| 6 | VI |
| 7 | VII |
| 8 | VIII |
| 9 | IX |
| 10 | X |
| Number | Roman numeral |
|---|---|
| 11 | XI |
| 12 | XII |
| 13 | XIII |
| 14 | XIV |
| 15 | XV |
| 16 | XVI |
| 17 | XVII |
| 18 | XVIII |
| 19 | XIX |
| 20 | XX |
| Number | Roman numeral |
|---|---|
| 30 | XXX |
| 40 | XL |
| 50 | L |
| 60 | LX |
| 70 | LXX |
| 80 | LXXX |
| 90 | XC |
| Number | Roman numeral |
|---|---|
| 100 | C |
| 200 | CC |
| 400 | CD |
| 500 | D |
| 900 | CM |
| 1,000 | M |
| 2,026 | MMXXVI |
How to convert Roman numerals by hand
Number to Roman numeral
- Split the number by place value: 1,994 = 1,000 + 900 + 90 + 4.
- Write each part: M + CM + XC + IV.
- Join them: MCMXCIV.
Roman numeral to number
- Find the subtraction pairs first (IV, IX, XL, XC, CD, CM) and read each as one value.
- Add everything else, largest to smallest: LXVI = 50 + 10 + 5 + 1 = 66.
Common mistakes: 99 is XCIX, not IC. 45 is XLV, not VL. CD is 400 but DC is 600, because order decides whether you add or subtract.
Frequently asked questions
- What is 4 in Roman numerals?
- 4 is IV: one before five, so 5 − 1. Writing IIII is not the standard form, because a symbol repeats at most three times.
- What is 99 in Roman numerals?
- 99 is XCIX: 90 (XC) plus 9 (IX). IC is wrong, because I can be subtracted only from V and X.
- Which Roman numerals can be subtracted?
- Only six pairs are standard: IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900). V, L and D are never subtracted.
- Is there a zero in Roman numerals?
- No. Roman numerals have no zero and no place value, so you read them symbol by symbol, adding when values go down and subtracting in the six pairs.
- What is the largest number this converter writes?
- In the standard form M can repeat only three times, so the largest number is 3,999, written MMMCMXCIX.
- Are Roman numerals on the HESI A2?
- Yes. Roman numerals are part of the HESI A2 math section, along with military time and household measures. In anatomy, the 12 cranial nerves are also numbered CN I to CN XII.
Keep going
Sources
All accessed October 27, 2026.
- OpenStax Contemporary Mathematics, 4.2 Early Numeration Systems
- The Math Doctors, How Roman Numerals Work
- OpenStax Anatomy & Physiology 2e, 13.4 The Peripheral Nervous System
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