Number Converters · Browser · Free

Binary Converter

Type a binary number into the field and press Convert. The decimal, hexadecimal, octal and ASCII / Unicode text forms of that value appear in cards below the button.

What this tool does

The form has a single field, Binary number, and one Convert button. Pressing the button fills the cards underneath with the same value written four ways: Decimal, Hexadecimal, Octal and ASCII / Unicode text. Copy writes a result to the clipboard, and Clear resets the form.

Only binary input is converted, so the numbers you type are read as base-two. A leading minus sign carries through to every card: entering -101 returns Decimal: -5; Hexadecimal: -5; Octal: -5; ASCII / Unicode text: .

Reading the results

Each card shows the value for that numeral base or character. For 1000001 the cards read Decimal: 65; Hexadecimal: 41; Octal: 101; ASCII / Unicode text: A, which is the shortest way to see a binary value and the character it stands for side by side.

The ASCII / Unicode text card is empty for some inputs, for instance for 1101.1, where the four results are Decimal: 13.5; Hexadecimal: D.8; Octal: 15.4; ASCII / Unicode text: .

The binary place-value formula

A binary digit stands for a power of two. Digits to the left of the point count whole units and double in value as you move away from the point, while digits to the right count fractions of those units, halving as you move away, so the first digit after the point is worth half of one. Adding the place values that a 1 occupies gives the decimal number.

Worked example: 1101.1 comes out as (1101.1)₂ = (13.5)₁₀ = (D.8)₁₆ = (15.4)₈, matching Decimal: 13.5; Hexadecimal: D.8; Octal: 15.4. Because each digit can only be 0 or 1, binary strings grow long fast, and very fine values are rounded: 0.000000000000000000001 in binary is about 0.00000047683715820313 in decimal, 0.000008 in hexadecimal and 0.0000001 in octal.