Hash & HMAC.
Type or drop a file and get every common digest at once. Add a key for HMAC. Paste an expected checksum and it tells you which algorithm matches. Nothing leaves your browser.
Digests
About this tool
SHA-1, SHA-256, SHA-384, SHA-512 and every HMAC come from the browser's built-in WebCrypto API, which is the same native implementation the browser uses for TLS. MD5 and CRC32 are not in WebCrypto, so they are small JavaScript implementations here; they are still everywhere in download checksums, ETags and legacy systems, which is why they are included, but neither should be used for anything security-related. Text is hashed as UTF-8 bytes; files are hashed byte for byte.
An HMAC is a hash keyed with a secret, used to sign webhooks (Stripe, GitHub, Slack all use HMAC-SHA256), API requests and tokens. Enter the shared secret as the key and the body as the text to reproduce what the sender computed, then paste the signature from the header into the expected field to confirm it matches. The verifier accepts hex or Base64 in either case and tells you which algorithm produced it.
Useful for: verifying a downloaded ISO or package against the published checksum, debugging a webhook signature mismatch, generating a fingerprint for a config file, and checking whether two files are identical without opening them. The key and the text stay in your browser; nothing is sent to this server or anywhere else.