How to convert between bases
Choose the base of the number you are entering, type it in, and the binary, octal, decimal and hexadecimal forms all appear instantly with one-click copy. Set the custom base field to anything from 2 to 36 for less common radices — base 32, base 36 short IDs, or whatever your problem needs. Input is validated against the chosen base: type a digit that does not belong (a 2 in binary, say) and the status line tells you, so you never get a silently wrong answer. Leading 0x, 0o and 0b prefixes are accepted and ignored.
The four everyday bases
Decimal (base 10) is how humans count, using digits 0–9. Computers, though, work in binary (base 2) — every value is ultimately a string of bits, 0 or 1, because that maps directly to off/on in hardware. Binary is precise but verbose, so two compact shorthands grew up around it. Octal (base 8) groups bits in threes and survives mainly in Unix file permissions like chmod 755. Hexadecimal (base 16) groups bits in fours using digits 0–9 then A–F, so one byte is exactly two hex digits — which is why hex is everywhere bytes are shown directly: colour codes (#2dd4a7), memory addresses, hashes, MAC addresses and binary dumps.
Any base from 2 to 36
Beyond the familiar four, this converter handles every base from 2 up to 36. The cap is 36 because that is how many single-character digits are available when you use 0–9 followed by the 26 letters A–Z. Base 16 stops at F (the 16th symbol); base 36 runs all the way to Z. Unusual bases show up more than you might expect — base 32 in some encoding schemes, base 36 to squeeze numeric IDs into short alphanumeric strings, base 26 in spreadsheet-column puzzles — and converting them by hand is tedious and error-prone, which is exactly what a tool is for.
Arbitrary precision with BigInt
Ordinary JavaScript numbers are 64-bit floats and lose exactness above 253, which would quietly corrupt large conversions. This tool sidesteps that entirely by using BigInt, JavaScript's arbitrary-precision integer type. That means you can convert a 200-digit decimal to hex, or a long binary string back to decimal, and every digit is exact — no rounding, no scientific-notation surprises. Conversion is implemented as exact integer arithmetic in the chosen radix, the same approach a CPU uses, just without a width limit.
Why convert bases locally
Base conversion is pure, deterministic integer maths — the textbook case for a real tool over an AI assistant, which can drop or transpose a digit in a long conversion and present it with total confidence. A deterministic converter applies the algorithm exactly and is right every time. Running it in the browser also means it is instant and works offline, and although a number is rarely secret, keeping everything local is simply the gitime.dev default: nothing you type is uploaded or logged.
- Four bases at once — binary, octal, decimal, hex.
- Any base 2–36 via the custom field.
- Arbitrary precision with BigInt — no 53-bit limit.
- Input validation against the chosen base, with clear errors.
- Local — exact, instant, nothing uploaded.
Frequently asked questions
- What bases can it convert?
- Binary, octal, decimal and hex at once, plus any custom base from 2 to 36 (digits 0-9 then A-Z).
- Can it handle very large numbers?
- Yes — it uses BigInt, so there is no 53-bit float limit; hundreds of digits convert exactly.
- Why is hex used so much in computing?
- Each hex digit is exactly four bits, so a byte is two hex digits — a compact, readable shorthand for binary.
- Is anything uploaded?
- No. All conversion runs locally in your browser.