Roman Numeral Converter

What Are Roman Numerals?

Roman numerals are a system of numbers that originated in ancient Rome. Instead of digits like 1, 2, or 3, this system uses combinations of letters from the Latin alphabet—I, V, X, L, C, D, and M. Each letter has a fixed value:

• I = 1
• V = 5
• X = 10
• L = 50
• C = 100
• D = 500
• M = 1000

These symbols are arranged in specific ways to form other numbers. For example, writing a smaller number before a larger one means subtraction (IV = 4) while writing it after means addition (VI = 6). Roman numerals don't use zero and are generally written in uppercase

You'll often see them in chapter numbers, clocks, historical events, or dates engraved on buildings.

What Are Arabic Numbers?

Arabic numbers are the standard numerical symbols most of the world uses today: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. They're part of the Hindu-Arabic numeral system, which includes place value and zero—two key elements that make modern math possible.

These numbers are far easier to calculate with, which is why they replaced Roman numerals in daily use. When we talk about converting between Roman numerals and "normal" numbers, we're really converting between Roman and Arabic numeral systems.

Converting Numbers to Roman Numerals

To convert a number to Roman numerals, you start by understanding the basic Roman symbols. Each letter represents a fixed value. For example, I is 1, V is 5, X is 10, L is 50, C is 100, D is 500, and M is 1000. Sometimes, these symbols are combined to form numbers, and in certain cases, a smaller value is placed before a larger one to indicate subtraction. For instance, IV represents 4, and IX stands for 9.

Let's say you want to convert the number 2024. The process begins with the largest symbol that fits into the number. One thousand fits into 2024, so we write "M". We subtract 1000 from 2024, and we're left with 1024. Since 1000 fits again, we write another "M". Now we have 24 left. Ten fits into 24, so we write "X", and again for the next ten, we add another "X". Finally, we're left with 4, which is a special case and represented by "IV". Putting it all together, 2024 becomes MMXXIV.

Let's Take another example to convert 42 from roman numerals to number. Here are the steps you can follow:

Step 1: Read from Right to Left

Start at the rightmost symbol and move left.

• I = 1 → keep it
• Another I = 1 → add
• L = 50
• X = 10 → smaller than L → subtract it

Step 2: Now add all:

• I + I = 2
• L − X = 40
• 40 + 2 = 42

Rule:

• If a smaller symbol is before a larger one, subtract
• If a smaller or equal symbol is after, add

Roman Numerals Chart (1–3999)