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Number Base Converter

Convert numbers between binary, octal, decimal, hexadecimal and any base up to 36. Type into any field and the others update as you go. Handles huge integers without losing precision and accepts 0x, 0b and 0o prefixes.

Everything runs locally in your browser. Your data never leaves your device.

base 2
base 8
base 10
base 16
base 36

Options

About the Number Base Converter

This tool converts a number between binary, octal, decimal and hexadecimal at once, plus one extra base of your choice up to base 36. Type into whichever field you have, and the other fields follow.

The math runs on big integers, so a 100-digit number converts exactly. No rounding, no precision cliff at 53 bits.

What you can do

  • Convert binary to decimal and decimal to binary.
  • Convert hex to decimal and decimal to hex.
  • Convert between binary, octal and hex directly.
  • Convert to and from any base up to 36.
  • Convert huge integers without losing precision.
  • Group digits into readable blocks of 3 or 4.

How to use the Number Base Converter

  1. 1Type the number into the field that matches the base you have. Prefixes like 0x, 0b and 0o work too.
  2. 2Read the converted value in every other field.
  3. 3For an unusual base, set the custom row to any base from 2 to 36.
  4. 4Copy any field with the button next to it.

Integers only, any size

The converter works on whole numbers, positive or negative, and underscores or spaces between digits are ignored, so 1_000_000 parses fine. Fractions are out of scope, since most bases cannot represent them exactly. Because everything is computed on arbitrary-size integers, values far beyond what a 64-bit number holds still convert digit-perfect.

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