Is it safe to use the Number Base online?

Yes — and ours is safer than most. Many free online tools quietly upload your files to their servers to do the work. We don't. Everything happens inside your browser on your own device, so your files never reach the internet. There's no upload step, no server copy, and no way for us (or anyone else) to see what you're working on.

Are my files uploaded to a server?

No. There's no server-side processing here. The whole tool is a tiny app that runs in your browser — we don't even have a server that could receive your files. You can confirm this by opening your browser's network tab while you use the tool: nothing leaves your device.

Do I need to sign up or pay?

No. There's no account, no email collection, no credit card. The tool is free to use as much as you want, on as many files as you want. We're supported by a few unobtrusive ads on the page — not by your data.

What's the maximum size?

Effectively unlimited — BigInt handles thousands of digits before performance becomes noticeable.

Why does my input turn red?

It contains characters invalid for that base (e.g. '9' in binary, 'g' in hex). The other fields keep their last valid values.

Number Base Converter

Convert any integer between binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16). Backed by BigInt so it handles numbers far beyond JavaScript's safe-integer limit.

Features

Four bases: binary, octal, decimal, hex
BigInt-backed: arbitrary-precision integers
Bidirectional: edit any field, all others update
Accepts common prefixes (0b, 0o, 0x) and underscore separators
Per-field copy buttons

How to number base converter

Enter a number — Type into any of the four fields.
See conversions — The other three fields update instantly.

Frequently asked questions

Is it safe to use the Number Base online?: Yes — and ours is safer than most. Many free online tools quietly upload your files to their servers to do the work. We don't. Everything happens inside your browser on your own device, so your files never reach the internet. There's no upload step, no server copy, and no way for us (or anyone else) to see what you're working on.
Are my files uploaded to a server?: No. There's no server-side processing here. The whole tool is a tiny app that runs in your browser — we don't even have a server that could receive your files. You can confirm this by opening your browser's network tab while you use the tool: nothing leaves your device.
Do I need to sign up or pay?: No. There's no account, no email collection, no credit card. The tool is free to use as much as you want, on as many files as you want. We're supported by a few unobtrusive ads on the page — not by your data.
What's the maximum size?: Effectively unlimited — BigInt handles thousands of digits before performance becomes noticeable.
Why does my input turn red?: It contains characters invalid for that base (e.g. '9' in binary, 'g' in hex). The other fields keep their last valid values.