Multi-Base Encoder / Decoder

Encodes/decodes data across six base formats: Base16 (hex), Base32 (RFC 4648), Base58 (Bitcoin alphabet), Base64, Base64URL, and Base85 (ASCII85), with live conversion and file upload.

Bitcoin alphabet (123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz), excluding the ambiguous 0, O, I, l. BigInt-based so arbitrarily large inputs work precisely.

No. All encoding runs in your browser via TextEncoder/TextDecoder and native BigInt. Text and uploaded binaries never leave your device.

Yes, the Multi-Base Encoder / Decoder is 100% free with no registration, no hidden fees, and no usage limits. All processing happens locally in your browser, ensuring complete privacy.

Yes, the Multi-Base Encoder / Decoder is fully responsive and works on smartphones and tablets. You can use it on any device with a modern web browser -- no app download required.

No account or registration is needed. Simply open the Multi-Base Encoder / Decoder in your browser and start using it immediately. There are no sign-up walls or usage restrictions.

The Multi-Base Encoder / Decoder supports a wide range of popular formats and languages. Check the tool interface for the full list of supported options.

Simply enter your input in the provided field, adjust any settings to your preference, and the tool will process it instantly. You can then copy the result to your clipboard or download it.

The Multi-Base Encoder / Decoder works in all modern browsers including Chrome, Firefox, Safari, Edge, and Opera. For the best experience, use the latest version of your preferred browser.

Both use a 64-character alphabet to turn binary into printable text, but they differ in three characters and in padding. Standard Base64 (RFC 4648) uses A-Z, a-z, 0-9 plus "+" and "/", and pads the output with "=" so its length is a multiple of four. Base64URL swaps the two problem characters "+" and "/" for "-" and "_", because plus and slash have special meaning in URLs and filenames, and it usually drops the "=" padding entirely. That makes Base64URL safe to drop into a query string, a path segment, or a JSON Web Token without further escaping. The decoded bytes are identical either way. This tool offers both as separate tabs, so you can encode a value as standard Base64 for an email attachment or Base64URL for a token, then use Swap to round-trip it.

No. Base64 and every other base encoding here are not encryption and provide no security at all. They simply remap raw bytes onto a smaller set of printable characters so binary data can travel through systems that only handle text, like email or URLs. Anyone who sees an encoded string can decode it instantly with no key or password, so a Base64 "obfuscated" secret is effectively plaintext. Treat encoding as a transport and compatibility step, never as a way to hide an API key, password, or token. If you need real secrecy, encrypt the data first with something like AES, then optionally Base64-encode the ciphertext for safe transport. This tool runs entirely in your browser precisely because the values you paste, such as JWTs or certificates, are sensitive even though they are not secret. Decode a string here to confirm just how readable encoded data really is.

Base64 expands data by roughly 33%, because it packs three bytes of input into four output characters, so the encoded result is about 1.33 times the original size before padding is added. That overhead is the price of being text-safe, and it is why large files sent as Base64, such as inline data URIs, weigh noticeably more than the raw binary. The other formats here have different ratios: Base16 (hex) exactly doubles the size at 2.0 since every byte becomes two characters, Base32 lands near 1.6, and Base85 (ASCII85) is the most compact text-safe option at about 1.25 because it packs four bytes into five characters. The live Stats panel in this tool shows your input size in bytes, the output character count, and the exact size ratio, so you can compare formats and pick the most efficient one for your use case.

A JSON Web Token is three Base64URL-encoded segments joined by dots: header, payload, and signature. To read the first two, copy the part before the first dot and decode it as Base64URL to see the header JSON, then do the same with the middle segment to reveal the payload claims such as "sub", "exp", and "iat". Use the Base64URL tab specifically rather than standard Base64, because JWTs use the URL-safe alphabet and omit padding, which a strict standard decoder may reject. The signature, the third segment, is a cryptographic hash and will not decode into readable text, so do not expect meaningful output from it. Because everything runs locally in your browser, you can paste a real production token here without it ever leaving your machine. Drop each segment into the decoder above to inspect exactly what a token is carrying.

Base32 (RFC 4648) encodes five bytes into eight characters, and when the input does not divide evenly into five-byte groups, "=" padding fills the final block so the length stays a multiple of eight. Its 32-character alphabet uses A-Z and 2-7, deliberately leaving out 0, 1, 8, and 9 along with letters that look like them, which makes encoded strings easier to read aloud, type by hand, or transcribe from a screen without errors. That human-friendliness is why Base32 is the standard for TOTP and two-factor authentication secret keys you scan or copy into an authenticator app, and for Tor onion addresses. It is also case-insensitive, so capitalization does not change the decoded result. This tool implements the RFC 4648 alphabet with padding, so you can encode a 2FA secret to share it or decode one to verify it matches what your app expects.