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Hash Calculator: MD5, SHA-256 & 25+ Algorithms Online

Hash calculator online: generate MD5, SHA-1, SHA-256, and 25+ algorithms from pasted text, with HMAC support for integrity checks.

Updated 2026-08-16

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Features

  • Support for 25 algorithms: MD2, MD4, MD5, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512, SHA3-224, SHA3-256, SHA3-384, SHA3-512, Keccak-256, Keccak-512, BLAKE2b-256, BLAKE2b-512, BLAKE2s-256, BLAKE3, RIPEMD-160, SM3, Whirlpool, CRC32, Adler-32, xxHash32, xxHash64
  • Real-time hash computation: results update instantly as you type or paste
  • HMAC support for SHA-1, SHA-224, SHA-256, SHA-384, and SHA-512
  • Uppercase / lowercase toggle: switch between upper and lower hex output
  • One-click copy: copy hash result to clipboard with a single click
  • Hash verification: paste an expected hash to instantly check match or mismatch (auto-detects algorithm by hash length)
  • Save results: save computed hash as a .txt file
  • Algorithm family grouping: browse 25 hashes organized by family (Legacy, SHA-2, SHA-3, BLAKE, 国密, Other) for easy selection
  • Real-time input length display: shows character and byte counts alongside any hash output

How to Use

  1. 1Select a hash algorithm from the pills: 25 algorithms including SHA-3, Keccak, BLAKE family, SM3, Whirlpool, xxHash, CRC32, and Adler-32.
  2. 2Type or paste text into the input area. The hash digest updates automatically in real time.
  3. 3Toggle UPPERCASE / lowercase to change the hex output format.
  4. 4Enable HMAC mode and enter a secret key to compute a keyed-hash message authentication code (SHA-1/224/256/384/512 only).
  5. 5Click the copy button to copy the hash, or use Save to save as a .txt file.
  6. 6Paste an expected hash into the Verify field to compare; the algorithm is auto-detected by hash length.
  7. 7How to quickly switch between algorithms: click different algorithm pills without changing your input text. Watch the hash output change instantly, letting you compare results across families.
  8. 8How to verify a hash from any source: copy the expected hash string, paste it into the Verify field, ensure the correct algorithm is selected (auto-detected by length), and check the match indicator.
  9. 9How to use HMAC for API authentication: enable HMAC mode, enter your secret API key, type the message to authenticate, and copy the resulting keyed hash for use in API request headers.
  10. 10How to compare outputs across algorithm families: select SHA-256, then switch to BLAKE3, then to SM3 without clearing input. Observe the different output sizes and formats of each family.

Frequently Asked Questions

What hash algorithms are supported?

25 algorithms across 6 families: Legacy (MD2, MD4, MD5), SHA-2 (SHA-1, SHA-224, SHA-256, SHA-384, SHA-512), SHA-3 (SHA3-224, SHA3-256, SHA3-384, SHA3-512, Keccak-256, Keccak-512), BLAKE (BLAKE2b-256, BLAKE2b-512, BLAKE2s-256, BLAKE3), 国密 (SM3), and Other (RIPEMD-160, Whirlpool, CRC32, Adler-32, xxHash32, xxHash64). SHA-1/256/384/512 use Web Crypto API for hardware acceleration; other algorithms use well-tested JavaScript and WebAssembly libraries. (See: FIPS 180-4)

Does HMAC work with all algorithms?

HMAC is supported for SHA-1, SHA-224, SHA-256, SHA-384, and SHA-512. MD2, MD4, MD5, Keccak, BLAKE2, BLAKE3, SM3, Whirlpool, RIPEMD-160, CRC32, Adler-32, and xxHash do not support HMAC. When HMAC mode is enabled, the secret key is combined with the message using the selected hash algorithm to produce a keyed digest.

Can I reverse or decrypt a hash?

No, hashing is one-way by design. For unsalted legacy algorithms like MD5, rainbow tables or dictionary attacks can match common plaintexts, but for SHA-256 and SHA-3 your only option is brute-forcing short, weak passwords. If the value is a password hash, use bcrypt or Argon2id instead of this tool.

Can I hash multiple texts at once?

There is no batch-list mode, but every input is hashed with all 25 algorithms simultaneously, so one paste produces every digest at once. To hash many files at once, use local commands instead: sha256sum file1 file2 on Linux/macOS, or Get-FileHash file1, file2 in PowerShell on Windows.

What is hash verification and how does it work?

Hash verification lets you check whether a hash you already have matches the hash of your current input. Paste an expected hash into the Verify field, and the tool automatically detects which algorithm it belongs to by its length (8 hex = CRC32 or Adler-32 or xxHash32, 16 = xxHash64, 32 = MD2/MD4/MD5, 40 = SHA-1 or RIPEMD-160, 56 = SHA-224 or SHA3-224, 64 = SHA-256/SHA3-256/Keccak-256/BLAKE2b-256/BLAKE2s-256/BLAKE3/SM3, 96 = SHA-384 or SHA3-384, 128 = SHA-512/SHA3-512/Keccak-512/BLAKE2b-512/Whirlpool) and shows a green checkmark if it matches or a red cross if it doesn't.

What is the difference between uppercase and lowercase?

Hash digests are typically displayed as hexadecimal strings. Uppercase (e.g. E5B3F2) and lowercase (e.g. e5b3f2) are both valid representations. The choice is cosmetic; tools and systems accept either format. Uppercase is common in Windows environments, while lowercase is more typical on Unix/Linux systems.

What is SM3?

SM3 is the Chinese national standard cryptographic hash function (GM/T 0004-2012). It produces a 256-bit (64 hex character) hash and is required for use in Chinese government and financial systems. First standardized in 2010, SM3 is considered cryptographically secure and is part of the 国密 (Guomi) cryptographic standard suite.

What is the difference between Keccak-256 and SHA3-256?

Keccak-256 is the original Keccak algorithm as submitted to the SHA-3 competition, with a padding scheme different from the final NIST SHA-3 standard. Keccak-256 (not SHA3-256) is used in Ethereum for things like transaction and message signing (EIP-191). The padding difference means Keccak-256('abc') produces a different output from SHA3-256('abc').

What is xxHash?

xxHash is a non-cryptographic hash function designed for speed; it can process data at RAM speed limits. xxHash32 produces an 8-character hex output and xxHash64 produces a 16-character hex output. It is not suitable for security purposes but is widely used in databases (e.g. PostgreSQL, Apache Cassandra), file systems (e.g. ZFS deduplication), and data networks for fast hash-based lookups.

Which algorithm should I choose for general-purpose hashing?

For general-purpose cryptographic hashing, SHA-256 is the most widely compatible choice with 128-bit security. For maximum performance, choose BLAKE3. For password hashing, don't use this tool; use bcrypt or Argon2id instead. For non-cryptographic checksums, xxHash64 provides the best speed.

Can I hash files with this online tool?

This tool accepts text input up to browser memory limits. For small files, you can copy and paste the file content. For large files (over several MB), consider using command-line tools (sha256sum, b3sum, openssl dgst) on your local machine for better performance.

What is the difference between SHA-2 and SHA-3?

SHA-2 (SHA-256, SHA-512) uses the Merkle-Damgard construction, while SHA-3 uses the Keccak sponge construction. They are completely different internally, with no shared code or mathematical structure. SHA-3 was designed as a backup in case SHA-2 is compromised. Both are NIST standards. (See: FIPS 180-4)

Why does my hash differ from other calculators?

Most differences come from invisible input bytes: a trailing newline, a byte-order mark, or UTF-16 encoding instead of UTF-8. Also confirm the exact algorithm and variant (SHA-256 vs SHA3-256, MD5 vs MD4), which produce completely different digests. Hash the same bytes on both sides and the outputs will match.

Why should I use this hash calculator online instead of downloading an app?

You don't need to download anything: this tool runs entirely in your browser, and every algorithm is computed locally, so your text and hashes never leave the device. Many downloadable hash calculator apps show ads, request broad permissions, or upload files to remote servers. If you still prefer a local tool, command-line utilities (sha256sum, openssl dgst) work offline on any OS; a browser tab gives you the same digests without installing anything.

Why does the SHA-256 of a file differ from the hash of its pasted text?

Because the file hash covers the file's exact bytes: line endings (CRLF vs LF), a byte-order mark, trailing newlines, and binary headers are all part of the input. Pasting text into this tool hashes only the characters, as UTF-8. If you want them to match, hash the file with the same content and encoding, or confirm that the published hash was computed over exactly the bytes you are comparing. This hash calculator sha256 mode computes the standard digest either way.