FNV-1a Hash Calculator
hash
All hashing runs in your browser. Data is never sent to any server.
Text Input
File Input
Drag & drop a file or click to select
1. How to Use
- Select bit size (32-bit default; 64 or 128 for longer hashes).
- Enter text or upload a file to compute FNV-1a hash.
- Click 'Generate FNV-1a Hash' for the result.
- Use for fast checksums, cache keys, or consistent hashing.
- Not for security—optimized for speed and distribution.
2. How It Works
FNV-1a: Start with hash = offset basis (e.g., 14695981039346656037 for 64-bit). For each byte: hash = hash XOR byte; hash = hash × FNV_prime (e.g., 1099511628211 for 64-bit); hash = hash mod 2^64.
Formula: h = offset_basis; for each octet o: h = (h ⊕ o) × FNV_prime mod 2^n. FNV-1a XORs before multiply (vs FNV-1 which multiplies before XOR); FNV-1a has better avalanche.
Primes: FNV-1a 32-bit uses 16777619; 64-bit uses 1099511628211; 128-bit uses 309485009821345068724781371; etc.
Not cryptographic: Inverses and collisions are easy to find. Use for hash tables, checksums, sharding—not passwords.
3. About FNV-1a
FNV-1a (Fowler–Noll–Vo) is a fast non-cryptographic hash with excellent distribution. This tool supports 32, 64, 128, 256, 512, and 1024-bit outputs.
This FNV-1a hash calculator computes hashes for text and files. Ideal for hash tables, URL hashing, and fast lookups.
All computation runs in your browser.
4. Advantages
- Speed: Extremely fast—minimal operations per byte.
- Distribution: Good for hash tables and similar strings.
- Simple: Easy to implement across languages.
- Configurable size: 32 to 1024 bits.
5. Real-World Use Cases
- Hash tables: Fast bucketing with good distribution.
- URL hashing: Consistent hashing for caches.
- Sharding: Partition data by FNV-1a of keys.
- Checksums: Quick non-cryptographic integrity checks.