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How to Read Roman Numerals

Summary

Roman numerals originated from ancient Rome and evolved from pictograms to letters like I, V, X, L, C, D, and M, representing numbers such as 1, 5, 10, 50, 100, 500, and 1,000. The system uses additive and subtractive rules—placing a smaller numeral before a larger one subtracts (e.g., IV is 4), while placing it after adds (e.g., VI is 6). Roman numerals were designed for clarity in communication, especially in military contexts, and remain in limited use today, such as in clocks and commerce.

Table of Contents

What are Roman Numerals?

Roman numerals may look like numbers. But they resemble letters like V, M, and C.

At first, the Roman numbers were pictograms. Then, they became similar to what we now know as Latin script.

History of Roman Numerals

As the Roman Empire grew and took in all of Europe, the numerals incorporated some Greek mathematical concepts. And with them, the letters that meant one thousand and one hundred. Some even suggest they may have copied the letter for fifty as well.

The first five Roman numerals

One

Just like the Chinese, Romans used a line to represent a single unit. But unlike their Asian counterparts, they used a vertical line.

Why?

Because they used fingers to count.

To this day, Italians use their fingers in a precise way when expressing numbers. They lift the index finger—in some regions, the thumb—to start counting.

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Two and Three

Stretching the index finger equals one. For two, you need to extend the middle finger. And to represent three, you point the thumb outwards.

For Romans, the thumb also meant Yay or Nay, depending on the direction it points out.

Today, some Italians may start counting by stretching their thumb. In that case, the order would be the thumb, index, and middle finger. Roman numerals depict the same scene by adding vertical lines.

Clock with roman numerals — Roman Numerals are often used on a clock

Four and Five

To understand how Romans wrote the number four, we must first look at the number five.

Just like the previous numbers, another gesture points to its meaning.

Have you ever raised your hand to attract someone’s attention?

The gesture is the same most people make when signaling a waiter. With the thumb and index finger out, the hand looks like gesticulating the letter V.

Over time, the symbol for five became the letter V. However, the fourth Roman numeral is IV. The reason is that by putting an index finger in front of the other hand, they could signal the number four from great distances. In other words, IV means one less than five.

Romans were soldiers, and they fought in battalions. In other words, they needed a reliable way to communicate on the battlefield. Also, they could not count on modern binoculars. So, they developed numbers that were easy to reproduce and understand from far away.

Number Position and Order

Romans used the same method to write the remaining numbers.

Here are the rules for creating Roman numerals:

You can only place one line before a greater number to indicate that it is one unit less. In the same way, you can use some symbols to subtract from bigger units as long as the overall method maintains its logic. More on this later.
The first letter can only be followed by a lesser numeral or a letter that represents a smaller number.
As Romans did not use spaces or commas in writing, if you read a character bigger than the one that comes next, the author must have listed another number.
Just like with the vertical lines, you cannot repeat a symbol more than three times in a row.

You just learned to count up to eight in the Roman numeral system!

Given these rules, you now know that you can only write numbers like 9, 14, 19, etc. by placing a vertical line before the letter that equals the following unit.

Similarly, you learned how to write three other numbers by adding vertical lines after the V. You can also understand why Romans added more letters to avoid confusion when writing numbers like 10, 15, and so on.

roman numerals cheatsheet — This chart shows all of the different Roman Numerals that are needed.

Other Symbols in the Roman Numerical Notation

Nine and Ten

The letter for ten is X. If you think about it, you will soon realize that an X is nothing more than two letters V stacked upon one another. Of course, one is upside down.

As the previous rules explained, we can add a vertical line to write 9. So, nine is IX.

Fifty

Romans kept using the same method to write all the numbers up to 50. They would double and triple the X to write numbers up to 39. But then, they reached a plateau.

At first, they drew a vertical line across the middle of the letter V to represent the number 50. They got this idea from the Greek letter psi (Ψ). But soon, usage morphed from a mix of the vertical line and the V to a more stylized form that later became the letter L.

Using an L was more practical. Also, it allowed for writing forty, which is ten less than fifty. That is, XL.

One Hundred, Five Hundred, And One Thousand

The Latin word for one hundred was centum. And the letter for the same figure is C. However, the two are not related.

As surprising as it may sound, the letter C is the lazy representation of the Greek letter theta (θ). Some scholars believe that the Romans had to use half of it because of another reason. That is, the Greek letter phi (Φ), which the Greeks used to write several numbers depending on where they put an apex.

In any case, the Romans started using the letter phi to write One Thousand. But at one point, they changed it into CIƆ. The number one thousand was the only one that required three characters. As you can imagine, that sparked confusion. So, the writers started connecting the three letters.

The first C slanted over the I in the middle. In the same fashion, the backward C leaned back toward the I.

This is why we now have the letter M!

Using the Roman Numeral D for 500

The letter D for 500 has a comparable origin as the M for 1,000. This letter was born because the letter D is what you get when you connect the I in the middle of CIƆ to the backward C.

The Romans thought of getting rid of the first C to halve the number One Thousand. Of course, this choice also avoided any mistakes. Often, the sculptor would carve the letter I and backward C deeply to prevent confusion. So, forming a new letter proved to be a more effective way to speed up the writing on stones and tablets without losing any meaning.

Roman Numerals Summary:

The upper case letter I represent Arabic 1.
The upper case letter V represents the Arabic 5.
The upper case letter X represents the Arabic 10.
The upper case letter L represents the Arabic 50. (not used in this document)
The upper case letter C represents the Arabic 100. (not used in this document)
The upper case letter D represents the Arabic 500. (not used in this document)
The upper case letter M represents the Arabic 1,000. (not used in this document)
A bar placed over a letter or group of letters multiplies that value by 1,000. (not used in this document)
If the letter to the right represents an equal or smaller value the numbers ADD. XXII is 22.
If the letter to the right is a larger value than the numbers SUBTRACT. IV is 4. Only I is used with V or X, X with L or C, and C with D or M.
There is no zero!
Both C and M often still appear in commerce mixed with Arabic therefore if someone orders a quantity of 5M, they want 5,000 not 5 million.
A few more samples: XCV = 95, XIII = 13, XCIX = 99, XLIX = 49

Roman Numerals Chart

The following is a Roman Numerals Chart showing the Roman Numerals in order:

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

Key Points

Roman numerals originated from pictograms and evolved into letters resembling Latin script.
Roman numerals were influenced by Greek mathematical concepts as the Roman Empire expanded.
The first five Roman numerals (I, II, III, IV, V) were derived from finger-counting gestures.
Roman numerals were designed for clarity in battlefield communication, using simple and distinct symbols.
Key rules for Roman numerals include subtraction (e.g., IV for 4) and limited symbol repetition (no more than three times).
The letter X for 10 is derived from two stacked Vs, and IX represents 9 (one less than 10).
The letter L for 50 evolved from a stylized version of the Greek letter psi (Ψ).
The letters C (100), D (500), and M (1000) have origins in Greek letters and practical adaptations for clarity.
Roman numerals lack a zero and follow specific addition and subtraction rules (e.g., XXII is 22, IV is 4).
Roman numerals are still used in commerce, where symbols like M represent 1000 (e.g., 5M means 5000).

Frequently Asked Questions

Q:What are Roman numerals and how do they differ from Arabic numbers?

A:Roman numerals are a numeral system that originated in ancient Rome, using letters from the Latin alphabet (such as V, M, and C) to represent numbers. Unlike Arabic numbers (0-9), Roman numerals do not include a zero and follow specific additive and subtractive rules for combining symbols.

Q:How did Roman numerals originate and evolve?

A:Roman numerals began as pictograms and evolved to resemble Latin script. As the Roman Empire expanded, they incorporated Greek mathematical concepts and letters. The symbols were influenced by counting gestures, such as using fingers, and practical needs like battlefield communication, leading to symbols like V (5) and X (10).

Q:What are the basic rules for writing Roman numerals?

A:The basic rules for Roman numerals include: 1) Only one smaller numeral can precede a larger one to indicate subtraction (e.g., IV for 4). 2) Numerals are additive if the following numeral is equal or smaller (e.g., XXII is 22). 3) Symbols cannot repeat more than three times in a row. 4) There is no zero in the Roman numeral system.

Q:Why is the number 4 written as IV in Roman numerals?

A:The number 4 is written as IV (one less than five) because Romans used gestures to communicate numbers from a distance. Holding up one finger (I) before an open hand (V) signaled four, making IV a practical representation for clarity, especially in military contexts.

Q:How are larger numbers like 100, 500, and 1000 represented in Roman numerals?

A:Larger numbers in Roman numerals use specific letters: C for 100 (from the Greek theta), D for 500 (derived from half of the symbol for 1000), and M for 1000 (originating from the connected letters CIƆ). A bar over a numeral multiplies its value by 1000 for even larger numbers.

Edward Savey

Edward Savey holds a Bachelor's degree in Political Science from the University of Georgia and a Master's degree in Public Administration with a focus on constitutional law from Georgetown University. He launched constitutionUS.com as its editor, striving to make complex constitutional topics accessible to the public.