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Number Base Converter
Binary, octal, decimal and hex — with the bits laid out and 64-bit exactness.
Why this exists
Systems work hops numeric bases constantly: permissions are octal, netmasks and MAC addresses are hex, feature flags are binary. Convert between them with the standard prefixes (0x, 0b, 0o) auto-detected, the byte's bits laid out with their weights, and BigInt underneath so 64-bit values convert without silent precision loss.
🔒 Runs in your browser — nothing is sent anywhere
Exact at any size — the maths runs on BigInt, so 64-bit values (file offsets, flag registers) convert without the precision loss ordinary JavaScript numbers hit past 253.
- Decimal
- 255
- Hex
- 0xff
- Octal
- 0o377
- Binary
- 0b11111111
8 bits · grouped: 1111 1111
The byte, bit by bit
1128
164
132
116
18
14
12
11
Each set bit contributes its weight — the same reading as file permissions (rwx = 4+2+1) and netmask octets.