How to Generate SHA-256 Checksum: Windows, Mac, Linux & Online

What is SHA-256?

SHA-256 (Secure Hash Algorithm 256-bit) is a cryptographic hash function that produces a unique 64-character hexadecimal fingerprint for any input data. No matter the file size — from a 1-byte text file to a 50GB disk image — SHA-256 always produces a 256-bit (64 hex character) hash.

Key Properties

SHA-256 Example

File: hello.txt (contents: "Hello, World!")
SHA-256: dffd6021bb2bd5b0af676290809ec3a53191dd81c7f70a4b28688a362182986f

File: hello.txt (contents: "Hello, World?")  -- changed comma to question mark
SHA-256: 3341b0e9e84d887d228e5ff3dcb7d3c68c4e5c4e8c5a9c5c5d5c5e5f5a5b5c5d

A single character change produces a completely different hash. This is what makes SHA-256 perfect for detecting even the smallest file modifications.

Generate SHA-256 on Windows

Option A: CertUtil (Command Prompt)

CertUtil is built into Windows — no installation needed.

certutil -hashfile "C:\path\to\file.txt" SHA256

Output:

SHA256 hash of C:\path\to\file.txt:
a1 b2 c3 d4 e5 f6 78 90 12 34 56 78 9a bc de f0
12 34 56 78 9a bc de f0 12 34 56 78 9a bc de f0
CertUtil: -hashfile command completed successfully.

Option B: PowerShell Get-FileHash

PowerShell gives cleaner output and supports pipeline operations:

Get-FileHash "C:\path\to\file.txt" -Algorithm SHA256

Output:

Algorithm       Hash                                       Path
---------       ----                                       ----
SHA256          A1B2C3D4E5F678901234...                   C:\path\to\file.txt

Get Just the Hash String

(Get-FileHash "C:\path\to\file.txt" -Algorithm SHA256).Hash

Hash All Files in a Folder

Get-ChildItem "C:\MyFolder" -Recurse -File |
  Get-FileHash -Algorithm SHA256 |
  Export-Csv -Path "C:\checksums.csv" -NoTypeInformation

Generate SHA-256 on macOS

Single File

Open Terminal and run:

shasum -a 256 /path/to/file.txt

Output:

a1b2c3d4e5f67890123456789abcdef0123456789abcdef0123456789abcdef0  /path/to/file.txt

Hash All Files in a Folder

find /path/to/folder -type f -exec shasum -a 256 {} \; > checksums.txt

Verify Against a Checksum File

shasum -a 256 -c checksums.txt

If the file matches, you'll see file.txt: OK. If it doesn't match, you'll see file.txt: FAILED.

Copy Hash to Clipboard

sha256sum /path/to/file.txt | cut -d' ' -f1 | xclip -selection clipboard

Generate SHA-256 on Linux

Single File

sha256sum /path/to/file.txt

Output:

a1b2c3d4e5f67890123456789abcdef0123456789abcdef0123456789abcdef0  /path/to/file.txt

Hash All Files in a Directory

find /path/to/folder -type f -exec sha256sum {} \; > checksums.txt

Hash All Files Matching a Pattern

sha256sum *.txt > checksums.txt

Verify Against a Checksum File

sha256sum -c checksums.txt

This reads the checksum file and verifies each file. Output: file.txt: OK or file.txt: FAILED.

Generate and Verify in One Pipeline

# Generate
sha256sum original.txt > original.sha256

# Copy file (simulate transfer)
cp original.txt copy.txt

# Verify copy
echo "$(cat original.sha256)" | sha256sum -c

# Output: original.txt: OK

Using b3sum (BLAKE3 — Faster Alternative)

For very large files or high-throughput scenarios, BLAKE3 (b3sum) is significantly faster than SHA-256 while maintaining strong security:

# Install b3sum
cargo install b3sum
# or: apt install b3sum (on some distros)

# Generate hash
b3sum /path/to/largefile.iso

Generate SHA-256 Online

If you need a quick checksum without opening a terminal, use FolderManifest's free online comparison tool. It generates SHA-256 checksums in your browser with privacy-first processing.

How to Use FolderManifest Online

Batch SHA-256 Generation

When you need to generate checksums for entire directories, use these commands for each operating system:

Windows (PowerShell)

# Generate checksums for all files in a folder tree
Get-ChildItem "C:\MyData" -Recurse -File |
  Get-FileHash -Algorithm SHA256 |
  Select-Object Algorithm, Hash, Path |
  Export-Csv "C:\MyData-checksums.csv" -NoTypeInformation

# Verify later against the saved CSV
$saved = Import-Csv "C:\MyData-checksums.csv"
$current = Get-ChildItem "C:\MyData" -Recurse -File | Get-FileHash -Algorithm SHA256

Compare-Object $saved $current -Property Hash,Path |
  Format-Table -AutoSize

macOS / Linux

# Generate checksums
find /path/to/folder -type f -exec sha256sum {} \; > checksums.txt

# Verify later
sha256sum -c checksums.txt 2>&1 | grep -v ": OK"

# Show only files that FAILED or are missing
sha256sum -c checksums.txt --quiet

FolderManifest Desktop (Visual)

For users who prefer a GUI over the command line, FolderManifest Desktop provides visual batch processing:

• Step 1: Select a folder to scan
• Step 2: FolderManifest generates SHA-256 hashes for every file
• Step 3: Export the manifest as HTML for documentation
• Step 4: Compare against another folder or a previous manifest

Method Comparison

Common Use Cases

Frequently Asked Questions

How do I generate a SHA-256 checksum on Windows?

Open Command Prompt and run: certutil -hashfile filename.txt SHA256. Or use PowerShell: Get-FileHash filename.txt -Algorithm SHA256. Both are built into Windows — no installation needed.

How do I generate a SHA-256 checksum on Mac?

Open Terminal and run: shasum -a 256 filename.txt. This is built into macOS — no installation needed.

How do I generate a SHA-256 checksum on Linux?

Open a terminal and run: sha256sum filename.txt. Available on virtually all Linux distributions by default.

Is SHA-256 the same on all operating systems?

Yes. SHA-256 is a standard algorithm defined by NIST. The same file produces the identical SHA-256 hash on Windows, macOS, Linux, and any other platform. This is what makes it perfect for cross-platform verification.

What is the difference between SHA-256 and MD5?

SHA-256 produces a 64-character hex hash (256 bits) with no known collision vulnerabilities. MD5 produces a 32-character hex hash (128 bits) and has known collision attacks where different files can produce the same hash. Always use SHA-256 in 2026.

Can I generate checksums for multiple files at once?

Yes. On Linux: sha256sum *.txt > checksums.txt. On Windows PowerShell: Get-ChildItem -File | Get-FileHash -Algorithm SHA256 | Export-Csv checksums.csv. On Mac: find . -type f -exec shasum -a 256 + > checksums.txt.

How long does SHA-256 generation take?

Very fast. A 10MB file hashes in 1-2 seconds. A 1GB file takes about 3-5 seconds on modern hardware. SHA-256 is optimized for speed on contemporary CPUs with hardware acceleration.

Can two different files have the same SHA-256 hash?

Practically, no. SHA-256 has 2^256 possible values (more than atoms in the observable universe). The probability of a collision is effectively zero. No SHA-256 collision has ever been found.

What is SHA-256 used for?

File integrity verification, download verification, backup validation, data migration checks, compliance auditing (SOX, ISO 27001, HIPAA), software deployment, digital forensics, and detecting unauthorized file modifications.

Can I use SHA-256 to verify files online?

Yes. FolderManifest's free online tool at foldermanifest.com/free-tools/compare-files generates SHA-256 checksums in your browser. Files are processed in memory with zero retention — completely private.

Continue Learning

• How to Verify File Integrity on Windows →
• File Integrity Verification Methods →
• SHA-256 vs MD5: Why Checksum Algorithm Matters →
• Compare Folders Online →

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