VITON13 SCHOOL · Maths
Roman numerals converter
Type a number or Roman letters — it converts both ways at once, shows how the total adds up and explains any non-standard spelling.
A number from 1 to 3999 or the letters I V X L C D M, in any case. It converts as you type.
Number → Roman numerals
MMXXVI
MMXXVI = 2026
How it adds up
- M1000
- M1000
- X10
- X10
- V5
- I1
MMXXVI = M + M + X + X + V + I = 1000 + 1000 + 10 + 10 + 5 + 1 = 2026
By place value2026 = 2000 + 20 + 6 → MM + XX + VI
The standard form covers 1 to 3999. Larger numbers once used a bar over a numeral (× 1000): that is history, not part of the standard form.
A date in Roman numerals
For a tattoo, an engraving or a clock face: the day, the month and the year are each written separately.
Type a date or press Today
Before a tattoo or an engraving, check each part against the chart: the converter writes the standard form.
The seven symbols
- I1
- V5
- X10
- L50
- C100
- D500
- M1000
1 to 100
Tens
Hundreds
Thousands
Seven rules in plain words
Seven letters stand for numbers.
I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000Write from the largest symbol to the smallest and add the values up.
MDCLXVI = 1000 + 500 + 100 + 50 + 10 + 5 + 1 = 1666I, X, C and M can be repeated, but never more than three times in a row.
III = 3, XXX = 30, MMM = 3000V, L and D are never repeated, because two of them make the next symbol.
X, not VV; C, not LL; M, not DDA smaller symbol before a larger one is subtracted.
IV = 5 − 1 = 4, IX = 10 − 1 = 9There are only six such pairs: I before V or X, X before L or C, C before D or M.
IV, IX, XL, XC, CD, CM — never IL or VXOnly one symbol can be subtracted, and each place (thousands, hundreds, tens, ones) is written on its own.
8 = VIII, not IIX; 99 = XCIX, not IC
Quiz: ten questions
Five questions each way, in a random order. Type the answer and press Check.
How to use the converter
- Type a number or lettersDigits from 1 to 3999 turn into Roman numerals, Roman letters turn into a number. The field works out which one you typed, in any case.
- Read the breakdownEvery symbol becomes a tile with its value, and a subtractive pair such as IV shows 5 − 1, so you can see why the total is right.
- Fix, convert a date, practiseA non-standard spelling is explained with the standard one offered. Dates, the chart, the seven rules and a ten-question quiz are in the tabs.
Why the standard form stops at 3999
The largest number the seven symbols can make under the three-in-a-row rule is MMMCMXCIX, which is 3999. Writing 4000 would need MMMM, four of the same symbol in a row, and the standard form does not allow that.
Larger numbers were written in other ways in Roman and medieval times. A bar drawn over a numeral, called a vinculum, multiplied it by 1000, so V with a bar meant 5000. Those forms were never fully standardised, so this converter describes them as history and does not build them.
The rules on this page are the standard form taught in schools today. Old inscriptions and many clock faces use other spellings, for example IIII instead of IV; the converter points such spellings out and shows the standard one.
Questions about Roman numerals
How do you write 4 and 9 in Roman numerals?
4 is IV (5 − 1) and 9 is IX (10 − 1). The same pattern gives 40 = XL, 90 = XC, 400 = CD and 900 = CM.
What is the largest number in Roman numerals?
In the standard form it is 3999, written MMMCMXCIX. Larger numbers were historically marked with a bar over the symbols, which multiplied them by 1000.
Is there a Roman numeral for zero?
Standard Roman numerals have no symbol for zero and no negative numbers, so the converter accepts whole numbers from 1 to 3999.
How do I write a date in Roman numerals?
Convert the day, the month and the year separately and join them with a dot or another separator. For example, 26.10.2026 becomes XXVI.X.MMXXVI.
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