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Binary to Decimal Converter

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Convert a binary number to decimal. Each bit, read right to left, contributes a power of 2 to the total: 1010 in binary equals 1·8 + 0·4 + 1·2 + 0·1 = 10 in decimal. Essential when reading bitmasks, microcontroller register values, embedded firmware constants and CPU flags. The converter accepts arbitrarily long binary strings and uses BigInt internally, so 64-bit values such as 1111111111111111111111111111111111111111111111111111111111111111 round-trip exactly.

From (Binary (2))

Binary (2)

Allowed: 0 and 1

To (Decimal (10))

Decimal (10)

Allowed: 0–9

Binary (2) → Decimal (10)

Quick reference table

Binary (2)	Decimal (10)
1	1
10	2
100	4
1000	8
10000	16
100000	32
1000000	64
10000000	128
100000000	256
10000000000	1024
10000000000000000	65536

Glossary

Binary (base 2)

The binary numeral system uses only two digits — 0 and 1 — and is the native number system of every digital computer. Each binary digit (bit) represents a power of 2: the rightmost bit is 2^0 = 1, then 2^1 = 2, 2^2 = 4, 2^3 = 8 and so on. Eight bits form one byte. Binary underlies every memory cell, register and network packet.

Decimal (base 10)

The decimal numeral system is the everyday number system used by humans, with digits 0 through 9. Each digit position represents a power of 10 — units, tens, hundreds, thousands. It is sometimes called base-10 or denary. All four bases on this page convert through decimal as a canonical integer value, so a round-trip such as binary → decimal → hex always produces the exact same number.

Related tools

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Convert integers between binary, octal, decimal and hexadecimal — with full BigInt support