Float Visualizer - Free Online IEEE 754 Tool | IconVault
Explore IEEE 754 floats bit by bit: click sign, exponent and mantissa bits of doubles and floats. Includes the 0.1 + 0.2 demo. Free.
Float Visualizer
Click IEEE 754 bits and see the exact decimal value
Bit explorer: click any bit to flip it
0x3fb999999999999a
sign
exponent
mantissa
Sign
0 = positive
Exponent
01111111011
raw 1019, unbiased -4, factor 2^-4
Mantissa
1001100110011001100110011001100110011001100110011010
value = (-1)^0 x 2^-4 x 1.10011001...
The 0.1 + 0.2 demo (binary64)
Step 1 of 4: 0.1 cannot be stored exactly
0.1 in binary is 0.0001100110011... repeating forever. A double keeps the closest 53 significant bits, which is very slightly more than 0.1. This is the exact value actually stored:
sign
exponent
mantissa
0.1000000000000000055511151231257827021181583404541015625
Decoded value
0.1
Exact decimal value
0.1000000000000000055511151231257827021181583404541015625
Neighbors:
- 0.09999999999999999
+ 0.10000000000000002
Anything between two neighbors rounds to one of them. That rounding is where 0.1 + 0.2 comes from.
5 of 5 free copies left. Flipping bits and stepping the demo are always free.
About this model
Bit layouts, rounding and exact values match IEEE 754 binary64 and binary32 precisely. Typing a decimal converts it exactly the way JavaScript's Number() does. Denormals, signed zero, infinities and NaN are all explorable: flip the exponent bits to all 1s and watch Infinity appear.
About this tool
IconVault's Float Visualizer opens up IEEE 754 floating point at the bit level: click any sign, exponent, or mantissa bit of a binary64 (double) or binary32 (float) and instantly see the exact decimal value, the neighboring values, and the unbiased exponent. Switch between hex, binary, and decimal views.
It ships with the famous 0.1 + 0.2 demo so you can see exactly which bits make the sum not quite 0.3. Built for students, game developers, and anyone burned by rounding errors. Free and runs fully in your browser.
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