Roman to Decimal Calculator

Use our free Roman to decimal converter to instantly parse any valid Roman numeral to decimal with a full token breakdown showing each letter's contribution, the running sum, and equivalents in binary, hex, and octal.

Math

Roman Numeral

Formula

Convert Roman numerals to decimal with a detailed token breakdown. Each letter or subtractive pair is evaluated, showing its individual value and the running sum. Also shows binary, hex, and octal equivalents.

Parse Roman tokens left-to-right, handling subtractive pairs

Percentage: The percentage value you want to apply

Number: The original number or value

Result: The calculated result

How It Works

1Enter a Roman numeral (I, V, X, L, C, D, M).
2Click Calculate to see the decimal value.

Examples

XIV to decimal

1.X=10 + IV=4 = 14

Result: 14

MMXXIV to decimal

1.M=1000 + M=1000 + X=10 + X=10 + IV=4 = 2024

Result: 2024

Frequently Asked Questions

I, V, X, L, C, D, M in standard subtractive notation (IV, IX, XL, XC, CD, CM). No more than 3 same symbols in a row.

No — both uppercase and lowercase work.

A smaller numeral before a larger one is subtracted: IV=4, IX=9, XL=40, XC=90, CD=400, CM=900.

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CalculateMe Team

Last updated: 2026-07-15

Roman to Decimal Calculator

Formula

How It Works

Examples

XIV to decimal

MMXXIV to decimal

Frequently Asked Questions

What Roman numerals are valid?

Is the input case-sensitive?

What is subtractive notation?

Related Calculators

Roman to Decimal Calculator

Formula

How It Works

Examples

XIV to decimal

MMXXIV to decimal

Frequently Asked Questions

What Roman numerals are valid?

Is the input case-sensitive?

What is subtractive notation?

Related Calculators