Roman Numerals: How They Work and How to Read Years

Roman numerals still appear on clocks, buildings, book chapters and film credits. The system is simpler than it looks once you know seven symbols.

The seven symbols

Symbol	Value
I	1
V	5
X	10
L	50
C	100
D	500
M	1,000

Adding

Symbols are written from largest to smallest and added together:

• III = 3
• VIII = 8 (5 + 3)
• XXVII = 27 (10 + 10 + 5 + 1 + 1)
• CLX = 160 (100 + 50 + 10)
• MMXXVI = 2026 (1000 + 1000 + 10 + 10 + 5 + 1)

Subtracting

When a smaller symbol comes before a larger one, subtract it:

Numeral	Meaning
IV	4 (5 − 1)
IX	9 (10 − 1)
XL	40 (50 − 10)
XC	90 (100 − 10)
CD	400 (500 − 100)
CM	900 (1,000 − 100)

Only I, X and C are used for subtraction.

Rules of thumb

1. Never repeat a symbol more than three times in a row. Write IV, not IIII (though IIII appears on some clock faces).
2. Write from left to right, largest first, except for subtractive pairs.
3. There is no zero in Roman numerals.

Reading years

Break the year into thousands, hundreds, tens and units:

• MCMXCIX = 1999 (M + CM + XC + IX)
• MMXXIV = 2024
• MDCCLXXVI = 1776 (M + D + CC + LXX + VI)

The Latin number words

Number	Latin
1	ūnus
2	duo
3	trēs
4	quattuor
5	quīnque
6	sex
7	septem
8	octō
9	novem
10	decem
100	centum
1,000	mīlle

You can see these in English words: unit, duet, triple, quadrant, quintet, sextet, September (originally the seventh month), octopus, decimal, century, million.

Where you'll see them

• Clock faces, chapter numbers, film copyright years
• Monarchs and popes: Elizabeth II, Benedict XVI
• Sporting events and film sequels

Tips

1. Learn the seven symbols.
2. Practise with years.
3. Use the dictionary to check number words.

Look up any word with English Latin Dictionary →