SHA-1 Hash & File Checksum

Calculate a 40-character SHA-1 hash for UTF-8 text or a local file. Compare an expected checksum, copy or download the digest, and understand why Git object IDs differ.

Calculate
0 characters
Result

Your result will appear here.

How to calculate and verify SHA-1

  1. Enter text or choose one local file; a selected file replaces the text as the source.
  2. Optionally paste the expected SHA-1 checksum without a filename, then calculate.
  3. Copy or download the full 40-character digest and check the comparison result.

Working with SHA-1 Hash & File Checksum

SHA-1 is retained for compatibility with existing systems and published checksums. It is not suitable for new collision-resistant security designs. Hashes are calculated from exact file bytes or UTF-8 text.

SHA-1 example: the standard abc test vector

Input
abc
Result
a9993e364706816aba3e25717850c26c9cd0d89d

Questions about SHA-1 Hash & File Checksum

What does the 40-character SHA-1 result represent?

It is the full 160-bit SHA-1 digest in lowercase hexadecimal. Text is encoded as UTF-8; files use their original bytes. Text is limited to 8 MiB and files to 32 MiB, processed in your browser.

Why is a file's SHA-1 different from its Git object ID?

In a SHA-1 repository, Git hashes an object header plus the content, not just the file bytes. For a blob, the header includes blob, the byte length and a null byte. This tool calculates raw SHA-1, not Git object IDs or HMAC-SHA-1. Use the HMAC tool for keyed hashes.

How do I compare a checksum, and why might it not match?

Paste only the expected hexadecimal hash. Comparison ignores letter case and surrounding whitespace. Input case, spaces, CRLF versus LF, a final newline or a UTF-8 BOM change the bytes and the digest. No text normalisation is applied; file names and paths are excluded.

Can SHA-1 be decrypted? Is it still secure?

SHA-1 is a hash, not reversible encryption. This tool does not recover original text or verify signatures. Collision attacks make SHA-1 unsuitable for new security-sensitive designs. Use it for existing checksum compatibility; prefer SHA-256 for new file checks and Argon2id or another dedicated scheme for password storage.

Are my files, tokens or text uploaded?

No. These tools process your input in your browser. The website serves the page and its code, but your input is not sent to a conversion server or saved in an account.

Related tools for your next step

Explore all developer tools

Encoding & Files

Move between text, bytes, URLs and embedded images without changing your original data.

Base64 Encoder & Decoder

Encode UTF-8 text to Base64 or decode standard and URL-safe Base64. Control padding and line wrapping.

Base64URL Encoder & Decoder

Convert text to URL-safe Base64 with the - and _ alphabet. Encode or decode unpadded Base64URL strings.

Image to Base64

Convert PNG, JPEG, GIF, WebP, SVG and other recognised image files to Base64 Data URIs in your browser.

Base64 to Image

Decode a Base64 image or Data URI, preview supported image types and download the original image bytes.

File to Base64

Encode any file to a Base64 string, with optional Data URI prefix, padding and MIME line wrapping.

Base64 to File

Turn Base64 strings and Data URIs back into downloadable files without changing the decoded binary data.

URL Encoder & Decoder

Encode and decode URL components, complete URLs and form values. Handle percent escapes and spaces correctly.

HTML Entity Encoder & Decoder

Convert text and Unicode characters to HTML entities, or decode named and numeric HTML character references.

Unicode Inspector & Escape Converter

Inspect Unicode code points, UTF-8 bytes and UTF-16 units, or convert JavaScript Unicode escapes to readable text.

Data & Text Inspection

Read structured data, inspect tokens and understand exactly what changed.

JSON Formatter, Minifier & Validator

Format, minify and validate JSON with exact large-number preservation, indentation options and recursive key sorting.

JWT Decoder

Read JWT headers and payloads, inspect expiry and activation times, and view claims without sending your token anywhere.

Text Diff Checker

Compare two texts by line, word or character. Highlight additions and removals while retaining spaces and line breaks.

Regular Expression Tester

Test JavaScript regular expressions with flags, match positions, capture groups and named groups in your browser.

Hashes, IDs & Schedules

Check file integrity, generate identifiers and make sense of times and recurring schedules.

MD5 Hash & File Checksum

Calculate an MD5 hash for text or a local file, and compare it with an expected checksum.

SHA-256 Hash & File Checksum

Generate SHA-256 hashes for text or files and check a downloaded file against its published checksum.

SHA-512 Hash & File Checksum

Calculate SHA-512 text and file hashes locally and compare full hexadecimal checksums.

CRC32 Checksum Calculator

Calculate standard CRC-32 checksums for text or files and compare eight-character hexadecimal results.

HMAC Generator

Generate HMAC-SHA-1, HMAC-SHA-256 and HMAC-SHA-512 with a UTF-8 or hexadecimal secret key.

UUID & GUID Generator

Generate random UUID v4 or time-ordered UUID v7 identifiers, individually or in batches.

Unix Timestamp Converter

Convert Unix seconds, milliseconds and ISO 8601 dates. View the same instant in UTC and any IANA time zone.

Cron Expression Parser

Validate five- or six-field Cron expressions and list upcoming runs in an IANA time zone, including daylight-saving changes.

Cron Expression Generator

Build a Cron expression from time fields or common presets, then preview its next scheduled times in your chosen zone.

Your input and files are processed on your device. Keep sensitive results out of shared clipboards and use a trusted device for private keys and tokens.