Converters · Number tools
Integer to Roman Numerals Converter
Convert any integer to Roman numerals instantly with this free number to roman numerals converter — the classic 1–3999 range with correct subtractive notation (IV, IX, XL, XC, CD, CM), plus extended overline (vinculum) notation all the way to 3,999,999. 100% client-side, nothing leaves your browser.
✓ Private by design — conversions run locally in JavaScript
Enter any whole number to convert integer to Roman numerals — the “Show your work” table breaks every conversion into its subtraction steps.
Roman numeral reference table
Every integer from 1 to 3,999,999 is built from these value–symbol pairs, applied largest-first. The six subtractive pairs are what keep symbols from repeating more than three times.
Standard pairs (1 – 3999)
| Value | Symbol | Value | Symbol |
|---|---|---|---|
| 1000 | M | 900 | CM |
| 500 | D | 400 | CD |
| 100 | C | 90 | XC |
| 50 | L | 40 | XL |
| 10 | X | 9 | IX |
| 5 | V | 4 | IV |
| 1 | I |
Extended pairs — vinculum (overline) ×1000
| Value | Symbol | Value | Symbol |
|---|---|---|---|
| 1,000,000 | M̅ | 900,000 | C̅M̅ |
| 500,000 | D̅ | 400,000 | C̅D̅ |
| 100,000 | C̅ | 90,000 | X̅C̅ |
| 50,000 | L̅ | 40,000 | X̅L̅ |
| 10,000 | X̅ | 9,000 | I̅X̅ |
| 5,000 | V̅ | 4,000 | I̅V̅ |
An overline multiplies a symbol by 1,000: V̅ = 5,000, X̅ = 10,000, M̅ = 1,000,000. Overlined forms are a modern scholarly convention — ancient Romans rarely wrote numbers this large.
How to convert a number to Roman numerals
To convert number to Roman numerals by hand — the same greedy algorithm this tool runs — repeat these four steps:
- Take the largest value that fits. Starting from 1,000,000 down to 1, find the biggest table value less than or equal to what remains.
- Append its symbol and subtract. Write the symbol, subtract its value from the remainder, and repeat until nothing is left.
- Let the subtractive pairs do the work. You never write IIII or VIIII — 4 is IV (5−1) and 9 is IX (10−1), which is why the table includes IV, IX, XL, XC, CD, and CM.
- Above 3999, switch to overlines. The same greedy loop continues with overlined symbols worth ×1000, so 4,000 becomes I̅V̅ and 1,000,000 becomes M̅.
2026 in Roman numerals
MMXXVI
1000 + 1000 + 10 + 10 + 5 + 1
3999 in Roman numerals
MMMCMXCIX
1000×3 + 900 + 90 + 9 — the largest standard form
4000 in Roman numerals
I̅V̅
Overline ×1000: 5000 − 1000 (vinculum notation)
Which tool do you need?
This tool: single numbers
Convert one integer — or a whole list — into Roman numerals, with step-by-step breakdowns and overline notation to 3,999,999.
Dates in Roman numerals
Writing a birthday, wedding date, or tattoo? A date needs day, month, and year converted separately — use our date to Roman numerals converter.
Roman numerals to numbers
Reading a numeral instead of writing one? Use our Roman-to-integer decoder — this page converts numbers to numerals only.
Frequently asked questions
How do I convert an integer to Roman numerals?
Use the greedy subtractive method: repeatedly subtract the largest Roman value that fits (from M = 1000 down to I = 1) and append its symbol. The six subtractive pairs — IV, IX, XL, XC, CD, CM — keep any symbol from repeating more than three times. The converter above shows every step: 2026 becomes 1000 + 1000 + 10 + 10 + 5 + 1, written MMXXVI.
What is 2026 in Roman numerals?
2026 in Roman numerals is MMXXVI: 1000 (M) + 1000 (M) + 10 (X) + 10 (X) + 5 (V) + 1 (I). Try it in the converter above to see the full step-by-step breakdown.
What is 3999 in Roman numerals?
3999 in Roman numerals is MMMCMXCIX — the largest number expressible with the standard seven symbols: 1000 + 1000 + 1000 (MMM), 900 (CM), 90 (XC), and 9 (IX). Anything larger needs overline (vinculum) notation.
Why can’t I write 4000 as MMMM?
Standard Roman convention never repeats a symbol more than three times in a row, so MMMM is not valid. This converter switches to vinculum notation above 3999: an overline multiplies a symbol by 1,000, so 4000 is written I̅V̅ (5000 minus 1000).
How do you write numbers bigger than 3999 in Roman numerals?
With vinculum (overline) notation: an overline multiplies a symbol’s value by 1,000. Wondering how to write 5000 in Roman numerals? It is V̅ — V with an overline (5 × 1,000). This converter supports numbers up to 3,999,999: 1,000,000 is M̅, and 3,999,999 is M̅M̅M̅C̅M̅X̅C̅I̅X̅CMXCIX. Note that overlined forms are a modern scholarly convention, not ancient Roman practice.
What are the seven Roman numeral symbols?
The seven basic symbols are I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, and M = 1000. Combined with the six subtractive pairs (IV, IX, XL, XC, CD, CM) they cover every integer from 1 to 3999 — see the full reference table above.
When do I use subtractive notation like IV and IX?
Use a subtractive pair when a smaller power-of-ten symbol sits directly before a larger one — and only in these six combinations: IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900. Other pairings are invalid: 49 is XLIX (40 + 9), never IL.
Is there a Roman numeral for zero?
No. The Romans had no zero and no negative numbers — the smallest Roman numeral is I (1). This converter rejects 0, negatives, and decimals with an honest error instead of guessing.
Free tool by NRTechStudio