Understanding Roman Numerals
Roman numerals are a numeral system originating in ancient Rome, used throughout the Roman Empire and still widely recognized today. They use combinations of letters from the Latin alphabet (I, V, X, L, C, D, M) to represent numbers.
The Seven Basic Symbols
I
1
V
5
X
10
L
50
C
100
D
500
M
1,000
How to Read Roman Numerals
Addition Rule
When a smaller numeral follows a larger one, add their values.VI = 5 + 1 = 6 | XII = 10 + 1 + 1 = 12 | CLXVI = 100 + 50 + 10 + 5 + 1 = 166
Subtraction Rule
When a smaller numeral precedes a larger one, subtract the smaller from the larger.IV = 5 - 1 = 4 | IX = 10 - 1 = 9 | XC = 100 - 10 = 90 | CM = 1000 - 100 = 900
Repetition Rule
A symbol can be repeated up to three times (I, X, C, M). The symbols V, L, and D are never repeated.III = 3 | XXX = 30 | CCC = 300 | MMM = 3000
Valid Subtractive Combinations
Units (1-9)
I can precede V and X
Tens (10-90)
X can precede L and C
Hundreds (100-900)
C can precede D and M
Example Breakdown: MCMXCIV (1994)
| Symbol(s) | Calculation | Value | Running Total |
|---|---|---|---|
| M | 1000 | 1000 | 1000 |
| CM | 1000 - 100 | 900 | 1900 |
| XC | 100 - 10 | 90 | 1990 |
| IV | 5 - 1 | 4 | 1994 |
Where Roman Numerals Are Used Today
Clock Faces & Watches
Many traditional clocks display hours in Roman numerals, with IIII often used instead of IV for aesthetic balance.
Movies & Sports Events
Film sequels (Rocky III), Super Bowl numbers (Super Bowl LVIII), and Olympic Games use Roman numerals.
Outlines & Lists
Academic papers, legal documents, and book chapters often use Roman numerals for hierarchical organization.
Monarchs & Popes
Kings, queens, and popes are numbered with Roman numerals: Queen Elizabeth II, Pope John Paul II.
Building Cornerstones
Construction dates on buildings are traditionally carved in Roman numerals (MCMXLVII = 1947).
Copyright Dates
Film and TV credits often display copyright years in Roman numerals at the end of programs.
Fun Fact: The Longest Year
The year 1888 has the longest Roman numeral representation in history: MDCCCLXXXVIII (13 characters). This uses every symbol except for the subtractive combinations.
Roman Numeral Reference Tables
Numbers 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 |
Hundreds (100-1000)
| Number | Roman |
|---|---|
| 100 | C |
| 200 | CC |
| 300 | CCC |
| 400 | CD |
| 500 | D |
| 600 | DC |
| 700 | DCC |
| 800 | DCCC |
| 900 | CM |
| 1000 | M |
Thousands (1000-3000)
| Number | Roman |
|---|---|
| 1000 | M |
| 1100 | MC |
| 1200 | MCC |
| 1300 | MCCC |
| 1400 | MCD |
| 1500 | MD |
| 1600 | MDC |
| 1700 | MDCC |
| 1800 | MDCCC |
| 1900 | MCM |
| 2000 | MM |
| 2100 | MMC |
| 2200 | MMCC |
| 2300 | MMCCC |
| 2400 | MMCD |
| 2500 | MMD |
| 2600 | MMDC |
| 2700 | MMDCC |
| 2800 | MMDCCC |
| 2900 | MMCM |
| 3000 | MMM |
Notable Numbers
Midpoint
L
50
Century
C
100
Half Millennium
D
500
Millennium
M
1,000
US Independence
MDCCLXXVI
1,776
Pre-Y2K
MCMXCIX
1,999
Millennium
MM
2,000
Current Year
MMXXIV
2,024
Next Year
MMXXV
2,025
Maximum Standard
MMMCMXCIX
3,999
20th & 21st Century Decades
MCM
1900
MCMX
1910
MCMXX
1920
MCMXXX
1930
MCMXL
1940
MCML
1950
MCMLX
1960
MCMLXX
1970
MCMLXXX
1980
MCMXC
1990
MM
2000
MMX
2010
MMXX
2020
All Subtractive Combinations
| Roman | Value | Meaning | Used For |
|---|---|---|---|
| IV | 4 | 5 - 1 | Units (4) |
| IX | 9 | 10 - 1 | Units (9) |
| XL | 40 | 50 - 10 | Tens (40) |
| XC | 90 | 100 - 10 | Tens (90) |
| CD | 400 | 500 - 100 | Hundreds (400) |
| CM | 900 | 1000 - 100 | Hundreds (900) |
Quick Memorization Tips
- I, V, X - Small numbers (1-39). Think: 1, 5, 10
- L, C - Medium numbers (40-399). Think: 50, 100
- D, M - Large numbers (400-3999). Think: 500, 1000
- Subtractive pairs: IV(4), IX(9), XL(40), XC(90), CD(400), CM(900)
- Never repeat: V, L, D are never repeated
- Max 3: I, X, C, M can repeat up to 3 times