Binary to Decimal Converter
Convert binary integers to decimal in your browser.
Free to use, with no sign up. Conversion runs in your browser; entries are not uploaded.
Result
Place-value steps: For source digits dₖ…d₁d₀ in base b, value = Σ(dᵢ × bⁱ). The target digits are the quotient-remainder representation of that integer in the target base. For hex and binary, each hexadecimal digit represents four bits.
Worked example: 11111111 Place-value breakdown: Unsigned: 128+64+32+16+8+4+2+1 = 255. As signed 8-bit two’s complement, it is −1.
Bounds: bases 2–36; 1–4096 input digits; only digits valid for the selected source base are accepted. Prefixes, signs, spaces within a number and separators are not accepted. Optional bit width is 1–4096. Signed interpretation reads a fitting source bit pattern as two’s complement; without it the input is unsigned.
How to use this tool
Enter digits and choose the source and target bases. Select Convert to see the result and place-value steps. Inputs are unsigned unless you choose signed interpretation and provide a bit width.
Frequently asked questions
Which bases are supported?
Source and target bases may each be any whole number from 2 through 36. Use digits 0–9 and letters A–Z, without prefixes or separators.
How does signed mode work?
Signed mode requires a bit width from 1 to 4096. The source digits are read as an unsigned bit pattern that must fit that width, then two’s-complement interpretation is applied. With no signed option, the value is unsigned.
What is 11111111 in decimal?
11111111 in binary is 255 as an unsigned decimal value. With signed 8-bit interpretation, it is −1.