Calculator form
Use the grid below. Results appear above this form after submission.Example data table
| Example | Input | CRC32 Hex | Unsigned Decimal |
|---|---|---|---|
| Empty string | [empty string] | 00000000 | 0 |
| Digits | 123456789 | CBF43926 | 3421780262 |
| Word | hello | 3610A686 | 907060870 |
| Uppercase word | CRC32 | F6151584 | 4128576900 |
| Name sample | OpenAI | 1ECD9FBE | 516792254 |
Formula used
CRC32 is a cyclic redundancy check based on modulo-2 polynomial arithmetic. The standard polynomial is 0x04C11DB7, and many software implementations use the reflected form 0xEDB88320.
CRC₀ = 0xFFFFFFFF Index = (CRC ⊕ byte) AND 0xFF CRCᵢ₊₁ = (CRC >>> 8) ⊕ Table[Index] CRCfinal = CRCn ⊕ 0xFFFFFFFFThis page calculates the final checksum, shows binary and decimal representations, and previews how the running CRC changes across the selected input bytes.
How to use this calculator
- Select the input mode that matches your source data.
- Enter text, hex, binary, base64, or upload a file.
- Choose an optional text encoding for text mode.
- Add an expected CRC32 value when you want verification.
- Pick the preview byte count for the graph and running preview.
- Press Calculate CRC32 to show the result above the form.
- Use the CSV or PDF buttons to export the current report.
FAQs
1. What does CRC32 measure?
CRC32 creates a 32-bit checksum from byte data. It is used to detect accidental transmission or storage errors, not to prove security or authorship.
2. Why can two different files share one CRC32 value?
CRC32 has a fixed 32-bit output, so collisions are possible. It is strong for routine error detection, but it is not collision resistant like modern cryptographic hashes.
3. Is CRC32 the same as a cryptographic hash?
No. CRC32 is designed for speed and error detection. Cryptographic hashes are designed to resist tampering, collisions, and deliberate attacks.
4. Why does encoding matter for text input?
CRC32 works on bytes, not visible characters. Different encodings can map the same text into different byte sequences, which changes the checksum.
5. Why do hex and binary modes ignore spacing?
Spacing is treated as formatting convenience. The calculator removes spaces so you can group bytes for readability without changing the underlying value.
6. What does the running CRC preview show?
It shows how the checksum evolves after each processed byte in the preview range. This is helpful when studying byte influence or debugging mismatched results.
7. Why is an empty input valid?
An empty byte stream still has a defined CRC32 result. For the standard initialization and final XOR used here, the checksum becomes 00000000.
8. When should I use the expected CRC field?
Use it when you already know the target checksum from documentation, another tool, or a protocol specification. The calculator then reports a direct match or mismatch.