SHA Checksum Calculator
Calculate SHA-1, SHA-256 and SHA-512 checksum length and verification time for a file.
About SHA Checksum Calculator
SHA-256 and SHA-512 are members of the SHA-2 family of cryptographic hash functions producing fixed-length digests — 256 bits (64 hex characters, 32 bytes) and 512 bits (128 hex characters, 64 bytes) respectively — regardless of input size. This calculator shows the expected output length and format that `sha256sum`/`sha512sum` would produce; the displayed digest is a deterministic but non-cryptographic illustrative placeholder (this page runs client-side without a bundled crypto library), not a substitute for the real command when verifying file integrity.
Formula
Output length
hex_chars = output_bits / 4; bytes = output_bits / 8
- B
- digest size in bits
Worked example
With the default values below, SHA Checksum Calculator returns Illustrative Hex Digest (not cryptographic) of 1cdb18a6af0fb3f8a2d24e37c734073747dcd0699d975cfbd09397a23ab7fc53. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Input Text
- hello world
- Algorithmone of SHA-256, SHA-512
- SHA-256
Results
- Illustrative Hex Digest (not cryptographic)
- 1cdb18a6af0fb3f8a2d24e37c734073747dcd0699d975cfbd09397a23ab7fc53
- Output Size (bits)
- 256
- Hex String Length (characters)
- 64
- Output Size (bytes)
- 32
Step by step
- 1Values used
- 2Output length
- 3Illustrative Hex Digest (not cryptographic)= 1cdb18a6af0fb3f8a2d24e37c734073747dcd0699d975cfbd09397a23ab7fc53
- 4Output Size (bits)= 256
- 5Hex String Length (characters)= 64
- 6Output Size (bytes)= 32
Assumptions and limits
- The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to whole numbers, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How do I compute a real SHA-256 checksum of a file on Linux?
`sha256sum filename` prints the 64-character hex digest followed by the filename. For SHA-512, use `sha512sum filename` (128 hex characters). Both read the file's actual bytes — always use the real command-line tool, not an illustrative web calculator, when verifying downloaded file integrity.
Why is SHA-512 sometimes faster than SHA-256 on 64-bit CPUs?
SHA-512 operates on 64-bit words, which map directly onto the native word size of modern 64-bit processors, so despite producing a longer digest it can outperform SHA-256 (which uses 32-bit words) per byte processed on such hardware.
Is SHA-256 still considered secure for integrity verification?
Yes — SHA-256 and SHA-512 have no known practical collision or preimage attacks and remain the standard choice for file integrity checks, TLS certificates, and package signing as of today. MD5 and SHA-1, by contrast, are considered broken for security purposes.