Fast non-cryptographic 32-bit/64-bit byte-stream hash function that XORs each byte into the state before multiplying by the FNV prime.
Compact metadata for implementation and discovery.
Fowler-Noll-Vo (FNV-1a) is a lightweight non-cryptographic hash function widely used in hash tables, symbol tables, and Bloom filters. By XORing the input byte before multiplying by the FNV prime (0x01000193 for 32-bit), FNV-1a achieves better avalanche dispersion on small integer and ASCII keys than FNV-1.
Quick facts
Runtime and memory behavior at a glance.
Best
O(n)
Average
O(n)
Worst
O(n)
Space
O(1)
Interactive Runtime & Memory Budget Calculator
Estimate wall-clock latency, operation count, and working memory for FNV-1a Hash across input scales.
428.6 µs
428.6 µs
128 B
h_{i} = ((h_{i-1} \oplus b_i) \times 16777619) \bmod 2^{32}32-bit FNV-1a round update.
Tested TypeScript and Python 3 implementations paired with unit tests covering edge cases, duplicate keys, and boundary conditions.
/**
* FNV-1a 32-Bit Non-Cryptographic Hash — UTF-8 byte-stream XOR-then-multiply with prime 16777619
* Time: O(n) | Space: O(1)
*/
export function fnv1aHash32(input: string | Uint8Array): number {
const bytes = typeof input === "string" ? new TextEncoder().encode(input) : input;
let hash = 0x811c9dc5;
for (let i = 0; i < bytes.length; i++) {
hash ^= bytes[i];
hash = Math.imul(hash, 0x01000193) >>> 0;
}
return hash >>> 0;
}Byte-by-byte XOR and 32-bit modular prime multiplication.
In JavaScript/TypeScript, use Math.imul(hash, 0x01000193) >>> 0 to preserve exact 32-bit unsigned modular multiplication.
What each reference supports for this entry.
Specification and official test vectors for FNV-1 and FNV-1a.
Open sourceGood next jumps from the relationship graph, ranked for useful discovery.
Provides fast bucket indexing for open-addressing and chained hash tables.
Faster on short trusted keys, whereas SipHash protects against adversarial HashDoS collisions.