File Hash Generator Online — SHA-256, SHA-512, SHA-1
Generate cryptographic hash of any file online. Supports SHA-1, SHA-256 and SHA-512. Free, browser-based.
A cryptographic hash (also called a checksum or digest) is a fixed-length fingerprint of a file's contents. If the file changes even by one byte, the hash changes completely. Hashes are used to verify file integrity — after downloading a file, you can compare its hash against the one published by the source to confirm the file has not been tampered with or corrupted. This tool uses the browser's built-in Web Crypto API to compute SHA-1, SHA-256, and SHA-512 hashes without uploading the file to any server.
How to use
- Drag and drop any file onto the upload area, or click 'Choose File' to select it.
- Select the hash algorithm: SHA-1, SHA-256, or SHA-512.
- Click 'Generate Hash' and copy the hex string from the output.
FAQ
What is a file hash used for?
File hashes are used for integrity verification. Software distributors publish the SHA-256 hash of their installer files. After you download the file, you generate its hash and compare it to the published value. If they match, the file is intact and unmodified. If they differ, the file may have been corrupted during download or tampered with. Hashes are also used in digital forensics, version control systems, deduplication systems, and password storage (for text, not files).
What is the difference between SHA-1, SHA-256, and SHA-512?
All three are members of the Secure Hash Algorithm family. SHA-1 produces a 160-bit (40 hex character) hash and is now considered cryptographically weak — it is vulnerable to collision attacks and should not be used for security-critical purposes. SHA-256 produces a 256-bit (64 hex character) hash and is the current standard for file integrity verification. SHA-512 produces a 512-bit (128 hex character) hash and is marginally more secure than SHA-256, though SHA-256 is sufficient for all practical purposes.
Why is MD5 not available?
MD5 is not available in the Web Crypto API because it is considered cryptographically broken and should not be used for security purposes. The Web Crypto API deliberately omits insecure algorithms. If you need an MD5 hash for compatibility with a legacy system, you would need a third-party JavaScript MD5 library, or use a command-line tool (md5sum on Linux/Mac, certutil on Windows).
What is the maximum file size for hashing?
Files up to 500MB can be hashed. The file is read into memory as an ArrayBuffer before being passed to the Web Crypto API, so the available RAM in your browser determines the practical limit. On most modern devices, files up to 500MB are handled comfortably. Very large files (gigabytes) may require a command-line tool.
How long does hashing take?
The time depends on the file size and your device's processing speed. SHA-256 hashing is very fast — a 100MB file typically hashes in under a second on modern hardware. SHA-512 is slightly slower. The Web Crypto API uses native browser code that is highly optimised for this operation.
Is my file uploaded to a server?
No. The hashing runs entirely in your browser using the Web Crypto API (window.crypto.subtle). Your file is never sent to any server. The hash is computed locally from the file's bytes. This is important for hashing confidential files — the file content remains private to your device.