Cache Hit Ratio & Average Access Time

Calculate the cache hit ratio, average memory access time (AMAT) and speedup from hits, misses and latencies, free online.

Cache hits

Cache misses

Hit time / latency (ms or ns)

Miss penalty / backend latency (same unit)

About this calculator

Hit ratio = hits ÷ (hits + misses). Average memory access time AMAT = hit time + miss rate × miss penalty. The speedup compared with always going to the slow memory is (miss time) ÷ AMAT. The same maths applies to CPU caches, CDNs, Redis/Memcached and browser caches.