Number Base Converter
Binary, octal, decimal and hexadecimal, converted exactly (big-integer arithmetic, no floating-point drift), with the positional working shown.
Example — 1010 in binary10 in decimal — A in hexadecimal, 12 in octal
How we got it — the example, step by step
- Read it positionally: 1×2^3 + 0×2^2 + 1×2^1 + 0×2^0 = 8 + 0 + 2 + 0 = 10.
- Then write 10 in each base by repeated division, keeping the remainders.
Check it backwards
Convert the binary row back: each 1 is worth its power of two, and the powers add to 10 — the same number in every row, written four ways.
Questions people also ask
Why does it only take whole numbers?
Fractions in other bases are a separate tool's job — many decimal fractions have no exact binary form, and this page would rather say so than print a long approximation without telling you.