FNV

FNV (Fowler-Noll-Vo) is a simple non-cryptographic hash that computes quickly via XOR and multiplication by a prime, used for hash tables and fingerprinting.

Purpose

Provides an extremely low-overhead non-cryptographic hash, suited to hash table key distribution and fast fingerprinting.

Mechanism

FNV-1: hash = (hash × FNV_prime) ⊕ byte; FNV-1a: hash = (hash ⊕ byte) × FNV_prime. The offset basis and prime depend on the word width (e.g. FNV-1a 32-bit uses 2166136261 and 16777619). Non-cryptographic, not collision resistant.

Use cases

Hash table key distribution
Fast deduplication fingerprints
URL routing hashes
Non-security checksums

Examples

Input
```
hello
```
Output
```
0x4f9f2cab
```
FNV-1a 32-bit

Common errors

Using FNV for cryptographic authentication: FNV is not cryptographic; use HMAC-SHA256

Related terms

MurmurHash is a non-cryptographic hash designed by Austin Appleby, achieving good distribution and high speed through multiply-and-rotate operations.

xxHash is an extremely fast non-cryptographic hash designed by Yann Collet, approaching memory bandwidth limits on modern CPUs, used with LZ4/Zstd compression.

CRC32 is a 32-bit cyclic redundancy check based on polynomial division over GF(2), used to detect transmission errors — not a cryptographic hash.

Related tools

Hash Calculator

Compute MD5, SHA-1, SHA-256, or SHA-512 hashes with hex or Base64 output. Free, private, and 100% client-side.

Fnv32 — pure client-side tool. Privacy-first, no server round-trip.

Fnv64 — pure client-side tool. Privacy-first, no server round-trip.

References