Roman numerals are a numbering system built from seven letters: I, V, X, L, C, D, and M. They still appear on clocks, book chapters, movie credits, and some dates or monuments.

If you want to read or write them correctly, you only need the symbol values, the subtractive rule, and a simple way to combine or break apart the numbers. This article gives you a quick reference and shows the conversion steps both ways.

Roman numeral symbols and values

The basic symbols are fixed. Once you know them, the rest is pattern matching.

  • I = 1
  • V = 5
  • X = 10
  • L = 50
  • C = 100
  • D = 500
  • M = 1,000

Roman numerals are usually written from left to right, from larger values to smaller values. When that pattern changes, subtraction may be involved.

For a broader overview of the system, the Wikipedia article on Roman numerals is a useful reference.

The main writing rules

Roman numerals are built by adding symbol values, but there are a few limits.

Additive notation

If a smaller symbol comes after a larger one, you add the values.

  • VI = 6
  • XII = 12
  • LX = 60

This is the most common pattern.

Subtractive notation

If a smaller symbol comes before a larger one, you subtract it from the larger symbol.

  • IV = 4
  • IX = 9
  • XL = 40
  • XC = 90
  • CD = 400
  • CM = 900

This rule is used to avoid repeating the same symbol too many times.

Repetition limits

Some symbols can repeat, but not forever.

  • I, X, C, and M can be repeated up to three times in a row.
  • V, L, and D are not repeated in standard Roman numerals.

So you write III, but not IIII in standard form. You write VIII, but not VVV.

How to read a Roman numeral

To convert a Roman numeral into a normal number, scan from left to right.

Use this simple method:

  1. Start with the first symbol.
  2. Look at the next symbol.
  3. If the next symbol is smaller or equal, add the current value.
  4. If the next symbol is larger, subtract the current value.
  5. Keep going until the end.

Example: XIV

Break it into symbols:

  • X = 10
  • I = 1
  • V = 5

Now read left to right:

  • X is followed by I, so add 10
  • I is followed by V, so subtract 1
  • V is the last symbol, so add 5

Total: 14

So XIV = 14.

Example: MCMXL

Break it into symbols:

  • M = 1,000
  • CM = 900
  • XL = 40

Add them as parts:

  • M = 1,000
  • CM = 900
  • XL = 40

Total: 1,940

So MCMXL = 1,940.

How to write a number in Roman numerals

To convert a normal number to Roman numerals, break it into parts from largest to smallest symbol and use subtractive forms where needed.

A practical method is:

  1. Start with the largest symbol that fits.
  2. Write it as many times as needed, but no more than three in a row.
  3. Use a subtractive pair instead of four repeats.
  4. Move to the next smaller symbol.
  5. Continue until the number is fully written.

A Roman numerals converter can check your answer quickly, but it helps to understand the steps first.

Example: 68

Start with the largest values:

  • 50 fits once: L
  • 10 fits once: X
  • 5 fits once: V
  • 1 fits three times: III

Combine them:

  • 68 = 68

So 68 = LXVIII.

Example: 94

Break 94 into parts:

  • 90 = XC
  • 4 = IV

Combine them:

  • 94 = 94

So 94 = XCIV.

Example: 2024

Break 2024 into parts:

  • 1000 = M
  • 1000 = M
  • 10 = X
  • 10 = X
  • 1 = I
  • 1 = I
  • 1 = I
  • 1 = I

That would be too repetitive in places, so use standard grouping:

  • 2000 = MM
  • 20 = XX
  • 4 = IV

Combine them:

  • 2024 = 2,024

So 2024 = MMXXIV.

A quick conversion table

A small reference table can save time when you are checking common values.

| Number | Roman numeral | |---|---| | 1 | I | | 4 | IV | | 5 | V | | 9 | IX | | 10 | X | | 40 | XL | | 50 | L | | 90 | XC | | 100 | C | | 400 | CD | | 500 | D | | 900 | CM | | 1000 | M |

These values are the building blocks for larger numbers. If you want to practice switching between formats, a base converter can help you notice how positional systems work differently from Roman numerals.

Common mistakes to avoid

Roman numerals look simple, but a few errors happen often.

1. Using the wrong subtractive pair

Only certain subtractive forms are standard:

  • I can come before V and X
  • X can come before L and C
  • C can come before D and M

That means IV and IX are valid, but IL and IC are not standard Roman numerals.

2. Repeating a symbol too many times

You can write III, XXX, CCC, or MMM in standard form, but not more than three repeats in a row.

So 40 is XL, not XXXX. And 90 is XC, not LXXXX.

3. Putting symbols in the wrong order

Roman numerals usually go from large to small, except when subtraction is used.

  • Correct: XVI
  • Incorrect: VXI

The order changes the meaning, so this is one of the easiest mistakes to spot.

4. Ignoring subtraction inside a longer numeral

Some numerals contain a subtractive pair in the middle, not just at the start.

Example:

  • 1949 = MCMXLIX

That breaks down as:

  • M = 1,000
  • CM = 900
  • XL = 40
  • IX = 9

So 1949 = 1,949.

Worked practice examples

If you want to get comfortable, work through a few examples in both directions.

From Roman to normal

Example: XXVIII

  • X = 10
  • X = 10
  • V = 5
  • I = 1
  • I = 1
  • I = 1

Add them:

  • 28

So XXVIII = 28.

Example: CDLXII

Break it into parts:

  • CD = 400
  • LX = 60
  • II = 2

Add them:

  • 462

So CDLXII = 462.

From normal to Roman

Example: 37

Split it:

  • 30 = XXX
  • 7 = VII

Combine them:

  • 37 = 37

So 37 = XXXVII.

Example: 864

Split it:

  • 800 = DCCC
  • 60 = LX
  • 4 = IV

Combine them:

  • 864 = 864

So 864 = DCCCLXIV.

If you want to check your own work, you can also use a calculator-style number tool to stay consistent while you practice. The goal is not memorizing every numeral at once, but learning the pattern.

When Roman numerals are still useful

You will still see Roman numerals in a few familiar places:

  • chapter headings
  • clock faces
  • monarchs and popes
  • movie and game credits
  • event editions
  • dates on buildings or monuments

In these uses, they are often decorative or traditional rather than practical. That is why many people only need to read them, not use them every day.

The best next step is to pick five numbers, convert them both ways, and check each one against a converter until the pattern feels natural.

Frequently asked questions

What are the Roman numeral symbols and values?
The seven symbols are I, V, X, L, C, D, and M. They stand for 1, 5, 10, 50, 100, 500, and 1,000.
What does subtractive notation mean in Roman numerals?
It means a smaller symbol placed before a larger one is subtracted instead of added. Common examples are IV, IX, XL, XC, CD, and CM.
Why is 4 written as IV instead of IIII?
Standard Roman numerals use subtraction to avoid four repeated symbols in a row. So 4 is written as IV, which is 4, instead of IIII.
How do you convert a Roman numeral to a normal number?
Read from left to right. Add a symbol if the next symbol is smaller or equal, and subtract it if the next symbol is larger.
How do you convert a normal number to Roman numerals?
Break the number into the largest possible Roman values, then combine them from left to right. Use subtractive pairs for values like 4, 9, 40, 90, 400, and 900.
Can V, L, or D be repeated in Roman numerals?
No, not in standard Roman numerals. Those symbols are used once at a time, while I, X, C, and M can be repeated up to three times.
Is there a simple way to check if a Roman numeral is written correctly?
Yes. Look for valid subtractive pairs, no more than three repeats in a row, and a general pattern from larger values to smaller ones. If you are unsure, compare your answer with a converter or reference table.

About this article

Written by Yahav Atia, WSO – the digital agency (wso.co.il) that owns and founded this site, with the help of AI, and passed automated quality checks before publication. Numbers in the worked examples were computed in code, not estimated.