Number Base Converter
Convert between binary, octal, decimal and hexadecimal — all at once. Type into any field and the rest update live, with a custom-base row for anything from base 2 to 36. It’s exact (BigInt-backed) and runs entirely on your device.
- 🔒 100% private — no uploads
- 🆓 Free, no watermark
- 📱 Works on any device
How to convert
- 1
Enter a number
Type into any field — binary, octal, decimal or hexadecimal. Every other base updates at the same moment.
- 2
Read every base at once
There’s no direction to set: all the common bases show side by side, plus a custom-base (2–36) row for anything else.
- 3
Copy what you need
Each row has its own copy button. Values are computed with BigInt, so even 64-bit hexadecimal stays exact.
Why use Number Base Converter?
100% private
Runs entirely in your browser — nothing you type is uploaded or logged.
All bases at once
Binary, octal, decimal, hexadecimal and any base 2–36, all live and in sync.
Exact, no rounding
BigInt math means huge values (64-bit and beyond) convert without precision loss.
Works on any device
No install, no account — any modern browser on desktop or phone.
Binary, octal, decimal and hex in one view
Rather than converting one pair at a time, every base updates together as you type — plus a custom row for any base from 2 to 36. The math uses BigInt, so 64-bit values (and beyond) stay exact where ordinary JavaScript numbers would silently lose precision past 2⁵³.
Why these four bases
Binary is what hardware actually stores; hex packs each group of four bits into one digit (one byte = two digits); octal survives in Unix file permissions (chmod 755); and decimal is for humans. Programmers hop between them constantly — masks in hex, permissions in octal, sizes in decimal.
Frequently asked questions
How do I convert binary to decimal?
Type your binary value into its row; the decimal row — and every other base — updates instantly.
Does it handle large / 64-bit numbers?
Yes. Values are computed with BigInt, so even 64-bit hexadecimal converts exactly, with no rounding.
Does anything get uploaded to a server?
No. The conversion runs entirely in your browser with JavaScript — nothing you type is uploaded, stored or logged, and it keeps working offline once the page has loaded.