Number Base Converter
Convert integers between decimal, hex, binary, octal, and any base up to 36
- Files never leave your device
- Runs in your browser
- Free, no sign-up, no watermark
3 digits
2 digits
8 bits
3 digits
2 digits
8-bit two’s complement
Click a bit to flip it.- Unsigned
- 255
- Signed
- -1
- Hex
- 0xff
- Oct
- 0o377
70
Bytes & characters
FF
255
·
As text (UTF-8): Not valid UTF-8 text.
IEEE-754 floating point
Type a decimal number to see its bit pattern, or edit the integer above to decode it.
00000000000000000000000011111111
- Sign
- 0 (+)
- Exponent
- 0 → 2-126
- Mantissa
- 0xff
Subnormal · 0x000000ff
How to use Number Base Converter
Convert whole numbers between decimal, hexadecimal, binary, octal and any base from 2 to 36, with no size limit. It also shows two's complement up to 128 bits with a clickable bit grid, the bytes in big- or little-endian order, and IEEE-754 float bit patterns.
- 1
Type a whole number into any field: Decimal, Hexadecimal, Binary, Octal or Custom base. The prefixes 0x, 0b and 0o work in every field.
- 2
Under Format, set Digit grouping, Show prefixes, Uppercase hex and the base for the Custom base field (2–36).
- 3
Choose a Bit width (Auto, 8–128) and Signed (two's complement), then click any bit in the grid to flip it.
- 4
Check Bytes & characters in Big-endian or Little-endian order, or type a decimal number in Float value to see its float32 or float64 bits.
Frequently asked questions
Is there a limit on number size?
Base conversions are exact for whole numbers of any size. The two's complement, bit grid and byte views go up to 128 bits.
Can it convert fractions like 0.1 to binary?
The base fields take whole numbers only. To see how a decimal fraction is actually stored, type it into Float value in the IEEE-754 floating point panel and read the sign, exponent and mantissa.
How do I see a negative number in two's complement?
Type it with a minus sign, for example -5, and pick a Bit width. The panel shows the signed and unsigned readings and the hex form for that width.
What does “This value needs more than N bits” mean?
The value doesn't fit the Bit width you chose, so only its low N bits are shown in the bit and byte views. Choose a larger width or Auto.
Can it show the bytes as text?
Yes. Bytes & characters lists each byte in hex and decimal with its ASCII character, and As text (UTF-8) shows the decoded text when the bytes are valid UTF-8.