Binary to Decimal
Convert binary numbers to decimal — instant, exact, any length.
How to use Binary to Decimal
- Paste or type the binary number — e.g. 11111111. Several values separated by spaces convert together.
- Read the decimal instantly in the output box: 11111111 → 255.
- Watch for the error message if a token contains anything besides 0 and 1 — it names the bad value.
- Click “Copy result” to take the decimal value into your work.
What is Binary to Decimal?
A binary to decimal converter reads a base-2 number — 1s and 0s — and produces its ordinary base-10 value. Each binary digit has a place value doubling from right to left (1, 2, 4, 8, 16…), and the decimal value is the sum of the places holding a 1: 11001 = 16 + 8 + 1 = 25.
This is the direction you need when reading what a computer wrote: interpreting a bit mask, a permissions field, a subnet octet or a homework answer. It is also the quickest sanity check when learning binary — write a number, convert back, see if you got it right.
About the Binary to Decimal
Paste binary into the input and the decimal value appears instantly. Space-separated groups each convert independently — paste a whole byte sequence like 11000000 10101000 and get 192 168 back, which is exactly how you'd decode the start of a 192.168.x.x IP address.
Input is validated: any character other than 0 or 1 is flagged with the exact offending token, so a stray 2 or letter in transcribed binary can't silently corrupt the result. BigInt math keeps arbitrarily long bit strings exact — a 128-bit value converts without rounding.
Runs entirely in your browser. For the opposite direction use Decimal to Binary; if your binary encodes text rather than numbers, Binary to Text is the tool you want.
Frequently Asked Questions
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Binary Numbers Explained: Converting To and From Decimal
Binary is the language of computers. Here is how base-2 works and how to convert between binary and decimal.
Read the guide