Roman Numeral Converter
Convert between decimal numbers and Roman numerals with step-by-step breakdown. Also convert years and dates. See also Date to Roman Numerals and Number to Words.
Decimal → Roman Numeral
Roman Numeral → Decimal
Year to Roman Numeral
MMXXVI
Roman Numeral Reference Chart (1–100)
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
100
C
200
CC
300
CCC
400
CD
500
D
600
DC
700
DCC
800
DCCC
900
CM
1000
M
2000
MM
3000
MMM
How Roman Numerals Work
Roman numerals use seven symbols: I (1), V (5), X (10), L (50), C (100), D (500), and M (1000). Numbers are formed by combining symbols additively from largest to smallest. When a smaller symbol appears before a larger one, it is subtracted — this is called subtractive notation. For example, IV = 4 (5 − 1), IX = 9 (10 − 1), XL = 40 (50 − 10), XC = 90 (100 − 10), CD = 400 (500 − 100), and CM = 900 (1000 − 100). A symbol is never repeated more than three times consecutively.
Roman Numeral Conversion Rules
Decimal → Roman: subtract largest possible value, append symbol
Roman → Decimal: if current < next, subtract; else add
Seven base symbols:
I=1 V=5 X=10 L=50 C=100 D=500 M=1000
Subtractive pairs:
IV=4 IX=9 XL=40 XC=90 CD=400 CM=900
Example: Convert 2024 to Roman Numerals
2024 − 1000 = 1024 → M
1024 − 1000 = 24 → MM
24 − 10 = 14 → MMX
14 − 10 = 4 → MMXX
4 = IV → MMXXIV
2024 = MMXXIV
Common Years in Roman Numerals
| Year | Roman Numeral |
|---|---|
| 1990 | MCMXC |
| 1995 | MCMXCV |
| 2000 | MM |
| 2005 | MMV |
| 2010 | MMX |
| 2015 | MMXV |
| 2020 | MMXX |
| 2021 | MMXXI |
| 2022 | MMXXII |
| 2023 | MMXXIII |
| 2024 | MMXXIV |
| 2025 | MMXXV |
| 2026 | MMXXVI |
| 2030 | MMXXX |
| 2050 | MML |
| 2100 | MMC |
Technical Details
Standard Roman numerals represent integers from 1 to 3,999. There is no symbol for zero — the concept did not exist in the Roman number system. The subtractive rule applies only to specific pairs: I before V or X, X before L or C, C before D or M. This converter validates input in both directions and includes round-trip verification to ensure the Roman numeral follows standard notation rules. The step-by-step breakdown shows exactly how each symbol is derived from the decimal value.
Frequently Asked Questions
What is 2024 in Roman numerals?
2024 in Roman numerals is MMXXIV. M=1000, M=1000, X=10, X=10, IV=4. Total: 1000+1000+10+10+4 = 2024.
Why is 4 written as IV instead of IIII?
Subtractive notation (IV) is the standard modern convention. However, IIII appears on some clock faces as a stylistic choice — this is called the "watchmaker's four."
What is the largest Roman numeral?
Using standard notation, the largest number is 3999 (MMMCMXCIX). Historically, a vinculum (overline) was used to multiply by 1000, allowing larger numbers, but this is not part of the standard system.
Is there a Roman numeral for zero?
No. The Romans had no symbol or concept for zero in their numeral system. The word "nulla" (meaning "nothing") was sometimes used in medieval texts.
Where are Roman numerals still used today?
Roman numerals are used for clock faces, movie copyright dates, Super Bowl numbering, book chapters, outlines, monarch names (Queen Elizabeth II), and architectural inscriptions.