How to use SHA-1 Hash Generator — Free Online SHA1 Checksum Tool
- 1Type or paste your text, or choose a file to hash.
- 2The SHA-1 hash is calculated as you type.
- 3Copy the hash you need to compare it against a published checksum.
About SHA-1 Generator
SHA-1 sits in the same awkward position as MD5: formally deprecated, practically everywhere. Git object IDs, older TLS certificates and a long tail of published checksums all use it.
The 2017 SHAttered research produced two different PDF files with the same SHA-1, which ended its usefulness as a tamper-evidence mechanism. It remains perfectly good at what Git uses it for — giving content a stable, unique-enough name — and at catching accidental corruption.
If you are choosing an algorithm rather than matching an existing one, choose SHA-256.
Frequently asked questions
Is SHA-1 broken?
For security purposes, yes. A practical collision was demonstrated in 2017, so SHA-1 can no longer prove a file has not been deliberately altered.
Why does Git still use SHA-1?
Git uses it to name objects rather than to defend against attackers, and it added collision detection after the 2017 attack. A transition to SHA-256 has been underway for years.
How long is a SHA-1 hash?
40 hexadecimal characters, or 160 bits, whatever the input size.
What should I use instead?
SHA-256 for anything new. Only use SHA-1 when matching an existing value you do not control.
Is it free?
Yes — unlimited use, no sign-up, no watermark and no limit on how many times you run it.