Math & School

Number base converter

Convert directly between binary, decimal, octal and hexadecimal.

Updated on May 25, 2026 Calculator, calculation path and examples on one page

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Calculator

Number

From base

In base

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Examples

255 in base 2.

Result (Base 2): 11111111

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FF to a decimal number.

Result (Base 10): 255

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1010 to a decimal number.

Result (Base 10): 10

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FAQ

Which number systems are supported?

Binary (base 2), octal (base 8), decimal (base 10) and hexadecimal (base 16).

How do I convert decimal to binary?

Dial from base 10 to base 2. For example, 255 equals 11111111.

What does FF mean in hexadecimal system?

FF corresponds to decimal 255. In the hex system, the letters A to F stand for the values 10 to 15.

Why does the computer see all four bases at once?

This allows you to directly compare a number in any common representation, not just the target base.

Can I also enter hex numbers with letters?

Yes. With base 16, the numbers 0 to 9 and the letters A to F are permitted.

Are decimal places supported?

No, the calculator works with whole numbers.

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Sources and notes

methodology: Conversion using decimal representation (place value system with base b).