What is a cache hit ratio?

The cache hit ratio is the share of requests served from cache rather than rebuilt by your server. Higher is faster and cheaper:

• A hit is served immediately - no database, no page build, no waiting.
• A miss costs the full round trip - and a low ratio means you are paying that repeatedly for identical pages.
• Common causes of a low ratio - cache-busting query strings, cookies set on every request, and very short cache lifetimes.

If your CDN or caching plugin reports the ratio, it is one of the few numbers that maps directly to both speed and hosting cost.