IEEE-754 Float ↔ Hex
IEEE-754 floating-point representation
Inspect the hexadecimal bit pattern of 32-bit and 64-bit floating-point values, or decode a bit pattern back into a number. The tool uses JavaScript DataView so byte order is handled explicitly.
Formula and method
A binary floating-point value contains a sign bit, biased exponent, and fraction. Some decimal values cannot be represented exactly in binary.
Worked example
The float32 value 1.0 has the hexadecimal representation 3F800000.
How to interpret the result
The hexadecimal output exposes the exact stored bit pattern at the selected precision. Float32 keeps fewer significant bits than float64, so converting the same decimal number can produce different rounded values. Special exponent patterns represent positive and negative infinity, NaN, zero, and subnormal numbers.
Important limitations
- NaN and infinity have reserved exponent patterns.
- Rounding may occur when converting decimal input.
Common questions
Why does 0.1 not round-trip exactly?
One tenth has a repeating expansion in binary. IEEE-754 stores the nearest representable value, which becomes visible when enough decimal digits are displayed.
What does big-endian hex mean here?
The hexadecimal string lists the most significant byte first for readability. The converter uses DataView with an explicit byte order so results do not depend on the device's native memory layout.
Related tools
Method and examples reviewed September 8, 2026.