Cache Hit Miss Calculator – Miss Rate and AMAT
Calculate cache miss rate, miss penalty, and Average Memory Access Time (AMAT).
About This Calculator
Calculate cache miss rate, miss penalty, and Average Memory Access Time (AMAT). Use the calculator above for instant results.
Worked Examples
- Miss rate: 1% | AMAT: 4 + 0.01×100 = 5 ns
Answer: 1% miss rate / 5ns AMAT
- Miss rate: 20% | AMAT: 4 + 0.20×100 = 24 ns
Answer: 20% miss rate
- AMAT from L2: L2-hit-time + 0.01×100
Answer: Cascaded AMAT calculation
Who Uses This Calculator?
Identify cache bottlenecks.
Optimize memory access patterns.
Cache performance analysis.
AMAT formula demo.
Common Mistakes to Avoid
❌ Low miss rate is not always enough
Even 1% miss rate with 100ns penalty adds significant time if the critical path is memory-bound.
❌ AMAT is average — not worst case
Individual cold misses can be much worse than AMAT. Prefetching helps hide miss latency.
Frequently Asked Questions
AMAT formula?
AMAT = Hit time + (Miss rate × Miss penalty). For multi-level: AMAT_L1 = HT_L1 + MR_L1 × AMAT_L2.
Cache miss types?
Compulsory (cold miss): first access to data. Capacity: working set exceeds cache. Conflict: different data maps to same cache line.
Hardware prefetching?
Modern CPUs prefetch data based on access patterns. Sequential access is typically prefetched; random access is not.