Cache Hit Rate Estimator
Estimate your cache hit rate from workload shape.
Your workload
Users phrase the same question many ways. FAQ-shaped.
System prompt + retrieved context + user message.
Drives provider-native cache projection (Anthropic 90% / OpenAI 50% off cached input tokens).
Used only for the cost math. Routing-based deployments would use multiple models in practice.
Estimated impact
Exact-match hit rate~10%
Semantic hit rate (on exact-miss traffic)~40%
Provider-native discount on input tokens~80%
Total traffic covered by Layer 1 + 2~46%
Monthly cost without caching$690
Monthly cost with 3-layer caching$300
Monthly savings$390 (57%)
Estimates use workload-typical hit-rate priors calibrated from production data. Real hit rates depend on prompt variability + cache TTL + threshold tuning. Prism runs all three layers concurrently — exact-match (SHA-256 Redis), semantic (BGE-small at 0.95 cosine), and provider-native passthrough (Anthropic 90% / OpenAI 50% off cached input tokens).
Frequently asked questions
- Is Cache Hit Rate Estimator really free?
- Yes — fully free, no email gate, no signup, no sales call. All Prism tools live on this page and similar dedicated tool pages.
- What data does Cache Hit Rate Estimator use?
- The calculations use current public provider pricing (Anthropic, OpenAI, Google) and Prism's published cache-economics math from production traffic. Nothing about your usage is captured — the calculator runs entirely in your browser.