Base Converter

Converts numbers between binary, octal, decimal and hexadecimal — type in any base and read the other three. The everyday translation layer between how people count and how machines address, mask and colour things.

How to use

1. Enter the number in whichever base you have.
2. Read the same value in the other three bases.
3. Hex digits run 0–9 then A–F; case does not matter.
4. For negative numbers in a fixed width, remember systems store them as two's complement — see below.

When you actually need this

• Reading a hex colour, memory address or error code as a decimal quantity.
• Building or checking a bitmask for flags and permissions.
• Working through subnet masks and IP maths.
• Checking what a value looks like in binary when debugging bitwise code.

Why hex, and what it maps to

One hex digit is exactly four bits, so a byte is always two hex digits — FF is 11111111 is 255 — and long binary strings compress four-to-one without any awkward remainder, which octal (three bits per digit) cannot say of 8-bit bytes. That clean mapping is why memory addresses, hashes and colour codes are written in hex. A caution on negatives: this converts values, but machines store negative integers as two's complement in a fixed width, so −1 in a 32-bit register reads FFFFFFFF — the width matters, and a plain base conversion of the magnitude will not match a register dump.

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FAQ

How precise are the conversion factors in Base Converter?

The factors are the internationally defined exact values — one inch is exactly 25.4 millimetres, one pound is exactly 0.45359237 kilograms, and so on. Results are computed at full floating-point precision and only rounded for display.

Can I convert between metric and imperial units in both directions?

Yes. Enter a value in any field and every other unit updates at once, so the conversion works in either direction without switching modes or pressing a button.

Why does the last decimal place sometimes look off?

Because many conversions are irrational in decimal form and browsers use binary floating point, the final digit can differ by a tiny amount. The displayed value is rounded sensibly for everyday use; for laboratory or engineering work, carry the unrounded figure through your own calculation.