Encoding Tools and Hash Generators
These 8 encoding tools and hash generators cover Base64, URL encoding, SHA-256 hashing, checksum comparison, JSON Web Tokens, MAC address formatting and bitwise operations. None of them sends your input anywhere.
8 tools
- Base64 Encoder and DecoderEncode text to Base64 or decode it back, with full Unicode support and the URL-safe alphabet.
- Bitwise CalculatorThe bitwise calculator applies AND, OR, XOR, NOT and all three shift operators, showing every result in decimal, binary and hexadecimal at the same time.
- File Checksum CalculatorThe file checksum calculator hashes a file with SHA-256 in your browser and compares it against a published value, so the file itself never leaves your machine.
- Hash CompareHash compare checks whether two checksums match, ignoring case and stray whitespace, and names the algorithm from the digest length so a mismatch is explained.
- Hash GeneratorGenerate SHA-1, SHA-256, SHA-384 and SHA-512 hashes in your browser via the Web Crypto API.
- JWT DecoderThe JWT decoder reads the header, payload and claims of a token in your browser, checks the expiry against now, and never sends the token off for verification.
- MAC Address FormatterThe MAC address formatter converts between five notations, and reads the OUI and the local and multicast bits so you can tell a real vendor address from one.
- URL Encoder and DecoderPercent-encode text three ways (query value, whole URL or form data) and decode it back.
Encoding, hashing and the difference between them
Encoding is reversible and carries no key. Base64 and percent-encoding both exist so data survives a channel that expects plain text, and anyone holding the result can turn it back. Neither protects anything, which is the single most common misunderstanding about Base64 in particular.
Hashing is one-way. A SHA-256 digest of a file cannot be turned back into the file, which is what makes it useful for proving a download arrived intact. The hash generator works on text and the file checksum calculator works on a file, and the two give different digests for the same visible content because the bytes differ.
The Base64 encoder converts text to UTF-8 bytes before encoding, which the browser btoa function does not. btoa works on Latin-1 and throws on any character above 255, so encoding a word containing an accent fails outright without that step. The decoder accepts the URL-safe alphabet and missing padding rather than rejecting them.
The JWT decoder reads a token header, payload and claims and checks the expiry against the current time. It does not verify the signature and deliberately cannot: verification needs the signing secret or the public key, and pasting either into a web page would hand it to whatever that page chooses to do with it.
Two tools sit beside these for adjacent jobs: the bitwise calculator, which applies AND, OR, XOR, NOT and the three shift operators with results in three bases at once, and the MAC address formatter, which converts between five notations and reads the vendor and administration bits.
Which tool for which task
Encoding and hashing look similar from outside and answer opposite questions.
| What you need | The tool |
|---|---|
| To move binary data through a text channel | Base64 encoder, handling Unicode correctly in both directions |
| To put a value safely in a URL | URL encoder, with the three percent-encoding variants exposed |
| To prove a download was not corrupted | File checksum calculator, then hash compare against the published value |
| To fingerprint a piece of text | Hash generator, which works on the text rather than on a file |
| To read the claims inside a token | JWT decoder, with the expiry checked against now |
| To work with bits directly | Bitwise calculator, showing decimal, binary and hexadecimal together |
Frequently asked questions
Is Base64 a form of encryption?
No. Base64 is a transport encoding with no key, so anyone holding the string can decode it in seconds. It exists so binary data can travel through channels that expect text. Use it for that, and use real encryption when the content actually needs protecting from a reader.
Why does hashing a file give a different result from hashing its text?
Because the bytes differ. Hashing a file covers every byte, including the trailing newline and any byte-order mark at the start. Pasting the same content into a text box usually changes line endings or drops that mark, and a single byte of difference changes the entire digest.
Can this decoder verify a JWT signature?
No, and that is deliberate. Verifying a signature needs the signing secret or the public key, and pasting either into any web page would be a serious mistake. The decoder shows the header, the payload, every claim and whether the token has expired, which covers inspection.
Should I still trust an MD5 or SHA-1 checksum?
For detecting accidental corruption, yes. A truncated or damaged download will not produce a matching digest under either algorithm. For proving a file was not deliberately tampered with, no: both have practical collision attacks, so use SHA-256 where the threat is an attacker rather than a bad connection.
Is my input sent anywhere when I use these tools?
No. Every one runs as JavaScript in your own tab and the site has no backend to receive anything. That matters most here, because the input to these tools is often a live credential, a private file or a token that would be worth stealing if it travelled anywhere.