Developer utility · binary to decimal converter
Binary to Decimal Converter
Convert a binary integer to decimal and other number bases with place-value steps. Spaces are accepted, which makes byte groups such as 01001000 01101001 easy to read. The page is useful for checking bit masks, classroom exercises and short encoded values.
Up to 4,096 characters. No value is sent to a server.
Your conversion results will appear here.
Choose an input format, enter a value and select Convert to see binary, decimal, hex, octal and text results.
Use the tool
How to use this converter
- 1
Enter 0s and 1s, with optional spaces between bytes.
- 2
Select Convert to calculate the decimal value.
- 3
Copy the decimal answer or inspect the weighted sum.
Understand the result
How it works
Each binary digit is multiplied by a power of 2 based on its position from the right. In 101010, the non-zero terms are 1×2⁵ + 1×2³ + 1×2¹, which equals 32 + 8 + 2 = 42. The converter adds those weighted values with BigInt so large binary inputs remain exact.
Practical notes
How binary place values work
Start at the rightmost digit with 2⁰ = 1 and double the place value as you move left: 1, 2, 4, 8, 16, 32 and so on. A 1 means that place contributes to the total; a 0 means it does not. This gives a reliable way to check the result without relying on a calculator.
For example, 1101 is 1×8 + 1×4 + 0×2 + 1×1 = 13. The converter displays the non-zero weighted terms in its steps so the arithmetic is easy to audit.
Practical notes
Spaces, leading zeroes and text decoding
Whitespace is ignored in numeric input, so 01001000 01101001 and 0100100001101001 produce the same integer value. The integer output removes unnecessary leading zeroes, while the byte sequence used for text decoding keeps the eight-bit groups and decodes them as UTF-8.
That distinction matters for values such as 01000001: as an integer it is 65, while as one UTF-8 byte it is the character A. If the bytes are not valid UTF-8, the numeric results still work and the Text row explains the decoding failure.
Quick reference
Examples
101010
42
1×2⁵ + 1×2³ + 1×2¹
01001000
72
The UTF-8 byte for H
1101
13
8 + 4 + 1
Common questions
FAQ
What is 101010 in decimal?
101010 in binary is 42 in decimal.
Can binary input contain spaces?
Yes. Whitespace is ignored in numeric input, so grouped bytes can be converted directly.
Why does the result include text?
The tool also checks the bytes as UTF-8. When the bytes are valid text, the decoded value appears in the Text result.
What is 1101 in decimal?
1101 is 13 in decimal: 1×8 + 1×4 + 0×2 + 1×1.
Do spaces change the binary value?
No. Spaces are ignored in numeric input and are useful for separating eight-bit byte groups when you are reading text data.