基数変換ツール

整数を2進・8進・10進・16進や2〜36の任意の基数へ変換。AND/OR/XOR・シフトのビット演算も搭載。完全オフライン。

Type a number in one field and read it in every other base at once. Base Converter keeps binary, octal, decimal, hexadecimal and one custom base of your choosing in sync as you type, then adds a clickable bit map and a full bitwise calculator underneath. Everything is computed with BigInt, so a 64-bit mask or a 512-bit hex literal round-trips exactly — no floating-point rounding, no silent precision loss. Bitwise results are evaluated inside an explicit 8, 16, 32 or 64-bit register in two's complement, the way the same expression would behave in C. Key features: - Edit binary, octal, decimal, hexadecimal and a custom base side by side — every other field re-renders as you type - Pick any custom radix from 2 to 36 with a slider, or jump to base 3, 5, 6, 7, 9, 12, 20, 26, 32 or 36 from the quick picks - Paste real-world literals: `0x`, `0b` and `0o` prefixes, a leading minus, and spaces, commas, underscores or quotes as separators are all accepted - Flip individual bits by clicking them in a byte-grouped bit grid at 8, 16, 32 or 64-bit width, with every bit labelled by index - Read the value's bit length, byte length, decimal digit count and popcount (set bits) at a glance - Run AND, OR, XOR, NOT, shift-left and shift-right on two operands entered in base 2, 8, 10 or 16, with a live expression preview such as `F0 ^ 3C` - See each bitwise result in all four common bases plus its signed and unsigned two's-complement readings, and push it straight back into the converter - Copy any single field, or grab every base at once as a labelled block with "Copy every base" - Get told when a value needs more bits than the selected register width, and which digits are legal when an entry is rejected - Toggle digit grouping and uppercase letters, and use the popup in any of 53 interface languages Privacy: all arithmetic happens inside the popup with the browser's own BigInt engine. The extension makes zero network requests, declares no host permissions, never reads the pages you visit, and collects no analytics. Only your own settings stay behind, on your device.