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About this tool
Generate a SHA1 hash of any text, in your browser.
The SHA1 Hash Generator computes the SHA-1 digest of any text you paste — a 160-bit value shown as 40 lowercase hexadecimal characters — using the browser's built-in Web Crypto implementation. The input is encoded as UTF-8 before hashing, which is what makes the output match what git, OpenSSL or a server-side library would produce for the same bytes. It is aimed at developers checking a checksum, a legacy signature or a stored digest rather than anyone choosing a hash for new security work.
Open SHA1 Hash Generator on AltFTool — it loads instantly in your browser.
Type or paste your text into the Text field, or click the 'hello world' chip in the Examples row to load the sample input.
The hash is computed in the browser as you type — there is no button to press. The Result panel shows the 40-character lowercase hex digest, with Algorithm (SHA-1) and Length (the JavaScript UTF-16 code-unit count of your input) in the cards below it.
Click Copy to put the whole result block — your Text line, the Result line, Algorithm and Length — on the clipboard, or Download to save that text as sha1-hash-generator.txt. Reset restores the default 'hello world' input.
Digests come from the browser's native SubtleCrypto engine, not a bundled JavaScript reimplementation that could drift.
The digest updates live with the input, so you can watch a single trailing space or newline change all 40 characters.
The character count sits next to the result, which is usually how you catch an accidental copied newline.
2aae6c35c94fcfb415dbe95f408b9ce91ee846ed. SHA-1 always produces 160 bits, printed here as 40 lowercase hex characters, no matter how long the input is — the empty string hashes to da39a3ee5e6b4b0d3255bfef95601890afd80709.
Not for anything security-critical. A practical collision was demonstrated in 2017 by the SHAttered research, which produced two different PDFs with the same SHA-1, and browsers and certificate authorities stopped trusting SHA-1 certificates before that. Use SHA-256 or better for signatures and integrity, and never use a bare hash of any kind for passwords — those need a purpose-built function such as bcrypt, scrypt or Argon2.
Almost always because the bytes differ, not the algorithm. A trailing newline, CRLF versus LF line endings, or non-ASCII characters encoded as something other than UTF-8 all change the digest completely. This tool encodes your text as UTF-8 with no added newline.
No. SHA-1 is one-way, and there is no arithmetic that reverses a 40-character digest into the input. Short or common inputs can still be found by looking them up in a precomputed table, which is exactly why hashing alone never protects a password.