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Roman Numeral Converter: Numbers and Dates

Type a number or a numeral and get the other one, with the steps shown. It also explains mistakes such as IIII, VX and IC.

Roman numeral–

Notation

Range

Private by design. Everything runs in your browser and is never uploaded.

The basics

What is a Roman numeral converter?

A Roman numeral converter turns a number into Roman numerals and Roman numerals back into a number, usually from 1 to 3,999. It adds the values of the symbols I, V, X, L, C, D and M, subtracting when a smaller one comes first, so MCMXCIV is 1,000 + 900 + 90 + 4 = 1994.

This converter works both ways as you type, shows the working, and says why a numeral is wrong, such as IIII, VX or IC. It also converts dates, and an extended range writes numbers up to 3,999,999 with an overline. For other kinds of code, try the binary translator or the Morse code translator.

The seven Roman numeral symbols
Symbol Value Example
I 1 2 = II
V 5 8 = VIII
X 10 30 = XXX
L 50 63 = LXIII
C 100 300 = CCC
D 500 700 = DCC
M 1000 2026 = MMXXVI
How it works

How to convert Roman numerals

Four steps, and the answer updates as you type.

01

Type a number or a numeral

Type digits in the Number box to get a numeral, or letters in the Roman numeral box to get a number. The other box fills in by itself, so there is no Calculate button.

02

Read the steps

Each symbol shows as a tile with its value, followed by the sum. MCMXCIV shows M, CM, XC and IV, then 1000 + 900 + 90 + 4 = 1994.

03

Pick the notation

Standard is the modern rule set. Clock face also accepts IIII for 4, and Additive accepts IIII, VIIII, XXXX and other forms that never subtract.

04

Go further

Switch the range to write 4,000 to 3,999,999 with an overline, or open the Date tab to turn a day, month and year into numerals with the separator you choose.

Reference

Roman numerals from 1 to 100 and beyond

The first hundred numbers, the six subtractive pairs, and round numbers up to 3,999,999.

Roman numerals from 1 to 100
Number Numeral Number Numeral
1 I 51 LI
2 II 52 LII
3 III 53 LIII
4 IV 54 LIV
5 V 55 LV
6 VI 56 LVI
7 VII 57 LVII
8 VIII 58 LVIII
9 IX 59 LIX
10 X 60 LX
11 XI 61 LXI
12 XII 62 LXII
13 XIII 63 LXIII
14 XIV 64 LXIV
15 XV 65 LXV
16 XVI 66 LXVI
17 XVII 67 LXVII
18 XVIII 68 LXVIII
19 XIX 69 LXIX
20 XX 70 LXX
21 XXI 71 LXXI
22 XXII 72 LXXII
23 XXIII 73 LXXIII
24 XXIV 74 LXXIV
25 XXV 75 LXXV
26 XXVI 76 LXXVI
27 XXVII 77 LXXVII
28 XXVIII 78 LXXVIII
29 XXIX 79 LXXIX
30 XXX 80 LXXX
31 XXXI 81 LXXXI
32 XXXII 82 LXXXII
33 XXXIII 83 LXXXIII
34 XXXIV 84 LXXXIV
35 XXXV 85 LXXXV
36 XXXVI 86 LXXXVI
37 XXXVII 87 LXXXVII
38 XXXVIII 88 LXXXVIII
39 XXXIX 89 LXXXIX
40 XL 90 XC
41 XLI 91 XCI
42 XLII 92 XCII
43 XLIII 93 XCIII
44 XLIV 94 XCIV
45 XLV 95 XCV
46 XLVI 96 XCVI
47 XLVII 97 XCVII
48 XLVIII 98 XCVIII
49 XLIX 99 XCIX
50 L 100 C
The six subtractive pairs
Pair Value How it is built
IV 4 5 minus 1
IX 9 10 minus 1
XL 40 50 minus 10
XC 90 100 minus 10
CD 400 500 minus 100
CM 900 1000 minus 100
Round numbers and milestones
Number Roman numeral
100 C
200 CC
300 CCC
400 CD
500 D
600 DC
700 DCC
800 DCCC
900 CM
1000 M
2000 MM
3000 MMM
3999 MMMCMXCIX
4000 IV typed as (IV)
5000 V typed as (V)
10,000 X typed as (X)
50,000 L typed as (L)
100,000 C typed as (C)
500,000 D typed as (D)
1,000,000 M typed as (M)
3,999,999 MMMCMXCIXCMXCIX typed as (MMMCMXCIX)CMXCIX
Notations

Standard, clock-face, additive and extended numerals

The same number can be written several ways. This converter shows all of them, and it tells you which rule a wrong numeral breaks instead of just refusing it.

The same number in four notations
Number Standard Clock face Additive Extended range
4 IV IIII IIII IV
9 IX IX VIIII IX
14 XIV XIIII XIIII XIV
40 XL XL XXXX XL
49 XLIX XLIX XXXXVIIII XLIX
90 XC XC LXXXX XC
400 CD CD CCCC CD
900 CM CM DCCCC CM
1994 MCMXCIV MCMXCIIII MDCCCCLXXXXIIII MCMXCIV
3999 MMMCMXCIX MMMCMXCIX MMMDCCCCLXXXXVIIII MMMCMXCIX
4000 Out of range Out of range Out of range IV typed as (IV)
4999 Out of range Out of range Out of range IVCMXCIX typed as (IV)CMXCIX
Common mistakes and the standard form
Written Why it is not standard Standard form
IIII Four I in a row. Standard numerals repeat a symbol at most three times. Clock faces use IIII anyway. IV (IIII on clock faces)
XXXX Four X in a row, which standard numerals write with a subtracting pair. Old additive numerals allow it. XL
VX V is never written before a larger symbol. Only I, X and C are subtracted. V
IC I may only come before V or X, so 99 is built as XC + IX. XCIX
IIX Only one small symbol may stand before a larger one, so 8 is V + III. VIII
VV V, L and D are never repeated. X
XM X may only come before L or C, so 990 is CM + XC. CMXC
LD L is never written before a larger symbol, so 450 is CD + L. CDL
VIV V is never repeated, even with other letters between the two. IX
MMMM Standard numerals stop at MMMCMXCIX (3,999). From 4,000 the thousands take an overline. none, use the extended range
Use cases

What people use a Roman numeral converter for

Years and anniversaries

Cornerstones, monuments, film credits and copyright lines often show a year in Roman numerals. Type 2026 to get MMXXVI, or open the Date tab for a full day and month.

Clock faces and watches

Dial designers often want IIII rather than IV. Switch the notation to Clock face and type each hour from 1 to 12 to see the whole dial, with IIII for 4 and IX for 9.

Names, titles and rulers

Monarchs, popes and family names carry numerals, such as Elizabeth II, Pope Leo XIV or a name ending in III. Convert one to check an order or to read it at a glance.

Chapters, outlines and volumes

Book volumes, chapter headings, outline levels and the acts of a play are often numbered this way. Paste a numeral to read its value, or write one for a heading.

Dates for gifts and ink

Wedding dates, birthdays and tattoos are a popular reason to convert a date. Pick the order and separator, then copy it. To work out an age from a birth date, use the age calculator.

Homework and puzzles

Check hand conversions with the steps and see which rule a wrong answer breaks. The mistakes table above lists the common ones, and the online time calculator covers clock arithmetic.

History

A short history of Roman numerals

Where the symbols came from, and why some of the rules are younger than you might expect.

Etruscan roots

The numerals derive directly from Etruscan number symbols. By the time the Colosseum was built, between CE 72 and 80, the classical form was already in place.

Adding first, subtracting later

Writing four as IIII and ninety as LXXXX was common in antiquity. Subtractive forms such as IV and IX became the standard only long after the Western Roman Empire fell.

No zero

Roman numerals have no symbol for zero. The word nulla was used for it, first attested in a 525 AD manuscript by Dionysius Exiguus, and an epacts table from about 725 used the letter N.

A slow retreat

Hindu-Arabic numerals reached Europe by the 11th century, yet Roman numerals stayed in common use into the 14th and 15th centuries. The switch was gradual rather than sudden.

Big numbers

A bar over a numeral, the vinculum, multiplies it by 1,000, so IV with a bar is 4,000 and XXV with a bar is 25,000. An older notation, the apostrophus, used C-shaped brackets around a number.

Clock faces

Many clock faces show 4 as IIII but 9 as IX, a practice that dates to the Wells Cathedral clock of the late 14th century. The clock in Elizabeth Tower uses IV.

Good to know

Things worth knowing about Roman numerals

A few rules explain most of the errors this converter catches.

  • Largest to smallest

    Standard numerals are written from the highest place to the lowest and skip empty places, so 1,009 is MIX.

  • Three in a row at most

    In standard form a symbol is repeated at most three times in a row. That is why 4 is IV and 40 is XL.

  • Only six pairs subtract

    IV, IX, XL, XC, CD and CM are the only subtractive forms in standard use. Anything else, such as IC for 99, is not standard.

  • Old numerals mixed the styles

    Gate 44 of the Colosseum is labelled XLIIII, which adds IIII after the subtractive XL. The Additive notation accepts forms like this one.

  • Dates need separators

    Run together, XIIX can be read more than one way, so keep a separator. Orders vary too: 4.VI.1789 and VI.4.1789 both mean 4 June 1789.

  • Private and forgiving

    Lowercase, spaces and the single-character Unicode numerals all work. Everything runs in your browser and nothing is uploaded.

Limits

What this Roman numeral converter does not do

Range and fractions

Standard numerals cover 1 to 3,999 and the extended range reaches 3,999,999. Zero, negative numbers and fractions are not converted. The Romans wrote fractions with S and dots, so for everyday fraction work use the fraction calculator.

Overlines in plain text

The bar is drawn with styling in the result. Copy result gives the Unicode combining overline after each letter, which some apps and fonts draw badly. The bracket form, such as (IV), is plain text and safe to paste anywhere.

Dates and spreadsheets

Dates run from year 1 to 3999 and use the modern Gregorian leap-year rule. In Excel, the ROMAN function gives an error above 3999 and offers styles from classic to simplified.

Sources

Where the facts come from

The rules, history and examples on this page come from these references. Competing explanations are labelled as such.

FAQ

Roman numeral converter FAQ

Short answers to what people ask most.

How do I convert a Roman numeral to a number?

Read the symbols from left to right, adding each value and subtracting when a smaller symbol comes before a larger one. LXIII is L + X + I + I + I, which is 50 + 10 + 1 + 1 + 1 = 63.

How do I write a number as a Roman numeral?

Split the number into thousands, hundreds, tens and ones, then write each part with the symbols of its place. 1994 is 1000 + 900 + 90 + 4, which is M + CM + XC + IV, so MCMXCIV.

What do the Roman numeral symbols stand for?

I is 1, V is 5, X is 10, L is 50, C is 100, D is 500 and M is 1000. Standard numerals combine them by adding, with six subtractive pairs: IV, IX, XL, XC, CD and CM.

What is the largest number in Roman numerals?

In standard form it is 3,999, written MMMCMXCIX. A bar over a letter, called a vinculum, multiplies it by 1,000, and this converter goes up to 3,999,999 when you turn on the extended range.

Why is IIII wrong, and why do clocks use it?

Standard numerals repeat a symbol at most three times, so 4 is IV. Many clock faces use IIII anyway, a practice traced to the Wells Cathedral clock of the late 14th century, and the reasons given, such as symmetry with VIII and easier casting, are debated.

Is VX or IC a valid Roman numeral?

No. Only I, X and C are subtracted, and only from the next two larger symbols: I from V or X, X from L or C, and C from D or M. So 5 is V and 99 is XCIX. The converter names the rule a numeral breaks.

Is there a zero in Roman numerals?

No. Roman numerals have no symbol for zero. The word nulla was used for it in some medieval manuscripts, with the earliest known instance in a 525 AD work by Dionysius Exiguus, but standard numerals start at I.

How do I write a date in Roman numerals?

Write the year, month and day as separate numerals and keep a separator between them. For example, 2026/11/09 is MMXXVI/XI/IX. The Date tab lets you choose the order and the separator.

What are 2026 and 1999 in Roman numerals?

2026 is MMXXVI (MM + XX + VI) and 1999 is MCMXCIX (M + CM + XC + IX). Type any year from 1 to 3999 to see its numeral.

How do I write 4000, 5000 or a million?

Use the overline, called a vinculum, which multiplies by 1,000. So 4,000 is IV with a bar, 5,000 is V with a bar and 1,000,000 is M with a bar. Turn on the extended range to see the bar, and use the bracket form (IV) when you need plain text.

Does the converter accept lowercase letters?

Yes. mcmxciv is read the same as MCMXCIV, spaces are ignored, and the single-character Unicode Roman numerals also work. Digits belong in the Number box.

Is anything I type uploaded or stored?

No. The conversion runs in your browser and nothing is sent to a server. The input appears in the page address only so that a shared link opens with the same numbers.