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Bitmask Calculator

Interactive bitmask calculator with bit toggling, binary/hex/decimal/octal conversion, bitwise operations (AND, OR, XOR, NOT, shift), and preset patterns for Unix file permissions, TCP flags, and HTTP methods. Runs entirely in your browser — your data never leaves your machine.

bitmask binary hex bitwise flags permissions calculator bits

Published June 1, 2026

All interactive tools run entirely in your browser. Your data never leaves your device.

How It Works

Enter a numeric value in decimal, binary, or hex. The calculator shows all representations and lets you toggle individual bits visually. Preset flag patterns provide labeled bits for common use cases.

Features

  • Multiple bases: enter values in decimal, binary (0b…), or hexadecimal (0x…)
  • Visual bit toggling: click any bit to set or clear it
  • 4 output formats: binary (grouped), hex, decimal, octal
  • Bitwise operations: AND, OR, XOR, NOT, left shift, right shift
  • 3 presets: Unix file permissions (rwx), TCP flags, HTTP methods
  • Configurable width: 4, 8, 16, or 32-bit mode
  • Set bit counter: shows how many bits are set
  • Copy support: copy any representation to clipboard
  • Private: runs entirely in the browser — no data transmitted

Use Cases

  • Unix permissions: visualize and build chmod values (755, 644, etc.)
  • Network protocols: decode TCP flag fields in packet analysis
  • Feature flags: design bitmask-based permission or feature flag systems
  • Low-level debugging: inspect and manipulate register values
  • API design: build bitmask enums for HTTP methods or access control
  • Education: learn binary arithmetic and bitwise operations interactively