CDN Offload Rate Calculator

Measure cache effectiveness by contrasting CDN edge traffic with origin fetches. Provide total requests plus origin misses, and optionally compare byte volumes to see how effectively the CDN shields infrastructure and transit bills.

Aggregate HTTP requests or hits served at the CDN edge over the reporting window.
Count of cache misses or origin fetches over the same window.
Optional. Leave blank to skip byte offload. Provide total CDN egress volume in gigabytes.
Optional. Leave blank to default to 0 GB. Provide the bytes your origin delivered back to the CDN in gigabytes.

Performance planning aid; confirm telemetry definitions with your CDN vendor when preparing compliance reports.

Examples

  • Total requests 12,000,000, origin requests 2,100,000, total egress 95,000 GB, origin egress 19,500 GB ⇒ Request offload 82.50%, origin hit ratio 17.50%, byte offload 79.47%.
  • Total requests 4,800,000, origin requests 960,000 with no byte data ⇒ Request offload 80.00% and origin hit ratio 20.00%, byte offload not evaluated.

FAQ

What if origin requests exceed total requests?

That scenario indicates mismatched telemetry windows or duplicate counting. The calculator requires origin requests to be less than or equal to total edge requests.

Should I use hits or distinct objects?

Use raw request counts when evaluating CDN performance. Object-level deduplication is useful for storage planning but hides bursty fetch patterns.

Why track byte offload separately?

Large media objects can dominate bandwidth even if request counts look healthy. Byte offload quantifies the egress avoided at origin and in upstream transit contracts.

Additional Information

  • Result unit: percentage of traffic served from the CDN cache versus origin.
  • Request offload evaluates cache hit efficiency; byte offload highlights bandwidth savings when payload sizes differ.
  • Use consistent reporting windows for both CDN analytics and origin logs so the denominator matches.

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