Number Base Converter
✓ Link copiedA fast, focused converter for number bases. Type an integer into any of the four fields — binary (base 2), octal (base 8), decimal (base 10), or hexadecimal (base 16) — and the other three update instantly as you type, with no button to press. It handles arbitrarily large integers exactly using big-integer math, so values far beyond the usual 32- or 64-bit limits never lose precision, and negative numbers are supported with a leading minus sign. Hexadecimal accepts upper- or lowercase letters and is shown in uppercase. Free, private, and runs entirely in your browser — nothing is ever uploaded.
How to use
Type or paste an integer into whichever base you're starting from — binary, octal, decimal, or hexadecimal. The remaining three fields convert live as you type, with no button to click. Prefix the value with a minus sign for negative numbers. Hexadecimal letters can be entered in any case. Click Copy next to any field to put that value on your clipboard, or Clear to reset every field.
Frequently asked questions
- How large a number can it convert?
- There is no practical limit. Conversions are computed with big-integer arithmetic rather than fixed-width numbers, so very large values — well past 64 bits — convert exactly with no rounding or overflow.
- Does it support negative numbers?
- Yes. Enter a leading minus sign (for example −FF in hexadecimal) and the sign is preserved across every base. Only whole numbers (integers) are supported; fractional or decimal-point input is rejected.
- Do I need to add a prefix like 0x or 0b?
- No. Each field already knows its base, so you type only the digits — no 0x, 0o, or 0b prefix. Any character that isn't a valid digit for that base is flagged as invalid so you can correct it.