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Checksum Verification Calculator

Work out checksum verification instantly with clear inputs, formula shown and shareable results.

About Checksum Verification Calculator

A checksum verifies that bytes arrived intact, but only a collision-resistant hash verifies they were not deliberately substituted. MD5 and SHA-1 both have practical collision attacks, so an attacker can craft two files with the same digest — which is why signed SHA-256 or better is required for software distribution, while MD5 remains adequate only for detecting disk or transfer corruption.

Formula

Hashing cost and strength

time = file bytes / (throughput x algorithm factor); collision resistance = digest bits / 2 for unbroken hashes

Worked example

With the default values below, Checksum Verification Calculator returns Time to hash the file of 7.67. Change any input above and every figure here is recalculated in your browser.

Inputs used

File sizeminimum 1 bytes
5,368,709,120 bytes
Algorithmone of MD5 (broken - integrity only), SHA-1 (deprecated), SHA-256, SHA-512, BLAKE3
SHA-256
Hashing throughputminimum 1 MB/s
700 MB/s

Results

Time to hash the file
7.67 s
Digest size
256 bits
Effective collision resistance
128 bits
Suitability
Suitable for security-relevant integrity verification

Step by step

  1. 1Values used
  2. 2Hashing cost and strength
  3. 3Time to hash the file= 7.67 s
  4. 4Digest size= 256 bits
  5. 5Effective collision resistance= 128 bits
  6. 6Suitability= Suitable for security-relevant integrity verification

Assumptions and limits

  • The result is derived only from the 3 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 2 decimal places, 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

Is a published checksum enough to trust a download?

Only if the checksum itself is authenticated, typically by a signature or by being served over a channel the attacker cannot modify. A checksum on the same compromised page proves nothing.

Why is BLAKE3 so much faster?

It is designed for parallelism and SIMD, hashing a tree of chunks concurrently rather than a single serial chain, so it scales with cores where SHA-2 does not.

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