Roman Numeral Converter

Online converter from Roman numerals to decimals. A free Roman-to-decimal (Arabic) translator, with conversion examples and a table of Roman numerals from 1 to 100.

Invalid Roman numeral.
Invalid decimal number. It must be between 1 and 3999.

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Table of Roman numerals from 1 to 100

1 I
2 II
3 III
4 IV
5 V
6 VI
7 VII
8 VIII
9 IX
10 X
11 XI
12 XII
13 XIII
14 XIV
15 XV
16 XVI
17 XVII
18 XVIII
19 XIX
20 XX
21 XXI
22 XXII
23 XXIII
24 XXIV
25 XXV
26 XXVI
27 XXVII
28 XXVIII
29 XXIX
30 XXX
31 XXXI
32 XXXII
33 XXXIII
34 XXXIV
35 XXXV
36 XXXVI
37 XXXVII
38 XXXVIII
39 XXXIX
40 XL
41 XLI
42 XLII
43 XLIII
44 XLIV
45 XLV
46 XLVI
47 XLVII
48 XLVIII
49 XLIX
50 L
51 LI
52 LII
53 LIII
54 LIV
55 LV
56 LVI
57 LVII
58 LVIII
59 LIX
60 LX
61 LXI
62 LXII
63 LXIII
64 LXIV
65 LXV
66 LXVI
67 LXVII
68 LXVIII
69 LXIX
70 LXX
71 LXXI
72 LXXII
73 LXXIII
74 LXXIV
75 LXXV
76 LXXVI
77 LXXVII
78 LXXVIII
79 LXXIX
80 LXXX
81 LXXXI
82 LXXXII
83 LXXXIII
84 LXXXIV
85 LXXXV
86 LXXXVI
87 LXXXVII
88 LXXXVIII
89 LXXXIX
90 XC
91 XCI
92 XCII
93 XCIII
94 XCIV
95 XCV
96 XCVI
97 XCVII
98 XCVIII
99 XCIX
100 C

How does the Roman numeral converter work?

It is a bidirectional converter: enter a Roman numeral or a decimal (1 to 3999) and the conversion happens instantly. Roman numerals are written with I, V, X, L, C, D and M.

How to convert Roman numerals to decimals?

To convert a Roman numeral to decimal, add or subtract the value of each symbol, from left to right:

Roman symbols

Seven main symbols are used:

  • I represents 1.
  • V represents 5.
  • X represents 10.
  • L represents 50.
  • C represents 100.
  • D represents 500.
  • M represents 1000.

Addition and subtraction rules

The key rules for conversion are:

  • If a Roman symbol is followed by an equal or smaller symbol, add its value to the result. Example: "VII" becomes 5 (V) + 1 (I) + 1 (I) = 7.
  • If a Roman symbol is followed by a larger symbol, subtract its value from the result. Example: "IV" becomes 5 (V) - 1 (I) = 4.
  • Symbols cannot be repeated more than three times in a row. If a symbol is repeated four times in a row, subtraction notation must be used. Example: "CD" becomes 500 (D) - 100 (C) = 400.

Conversion examples

Some examples:

  • "XII" becomes 10 (X) + 1 (I) + 1 (I) = 12.
  • "XXI" becomes 10 (X) + 10 (X) + 1 (I) = 21.
  • "XLV" becomes 50 (L) - 10 (X) + 5 (V) = 45.

Why does the converter only go up to 3999?

Classical notation uses I, V, X, L, C, D and M, and does not allow more than three M in a row. That is why the usual range is 1 to 3999 (MMMCMXCIX). From 4000 onward, a bar over the symbol multiplies it by 1000, and that format is not included in this converter.