Computer & IT
Cache Hit Infrastructure Savings Calculator
Split current and proposed requests into hits and misses, calculate origin compute and egress, price cache delivery, include incremental platform cost, and report monthly savings and origin-load reduction.
Current cache hits (millions)-
Current origin requests (millions)-
Proposed cache hits (millions)-
Proposed origin requests (millions)-
Avoided origin requests (millions)-
Current modeled delivery cost-
Proposed modeled delivery cost-
Modeled monthly infrastructure savings-
Modeled cost reduction-
Origin request reduction-
Platform cost per shifted million-
Decision view
Current versus proposed cache traffic split and cost bridge
Current versus proposed cache traffic split and cost bridgeParallel request flows show cache hits and origin misses, while the cost bridge includes compute, egress, cache serving, and incremental platform expense.
Exact scenario comparisonProposed cache hit rate (%) changes while all other entered assumptions remain constant.
| Proposed cache hit rate (%) | Current cache hits (millions) | Current origin requests (millions) | Proposed cache hits (millions) | Proposed origin requests (millions) | Avoided origin requests (millions) | Current modeled delivery cost | Proposed modeled delivery cost | Modeled monthly infrastructure savings | Modeled cost reduction | Origin request reduction | Platform cost per shifted million |
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How to use Cache Hit Infrastructure Savings Calculator
- Use request counts from the same billing and measurement period.
- Measure hit rate at the layer that actually prevents origin processing.
- Enter marginal infrastructure and transfer rates, not unrelated total platform spend.
Calculator guide
Understanding Cache Hit Infrastructure Savings Calculator
A cache hit removes an origin request only when traffic actually shifts. The economic value of that shift combines avoided origin compute and egress, added cache-serving cost, and any incremental platform fee.
Detailed calculation process
Detailed cache traffic and infrastructure-cost calculation
The default case evaluates 120 million requests per month, moving from a 75% to 90% cache hit rate.
General formula: H_0=Q*h_0M_0=Q-H_0H_1=Q*h_1M_1=Q-H_1A=M_0-M_1C_0=M_0*c_o+H_0*c_c+M_0*10^6*b/1048576*c_eC_1=M_1*c_o+H_1*c_c+M_1*10^6*b/1048576*c_e+FS=C_0-C_1 Requests are expressed in millions for compute and cache rates, then expanded to individual requests for KB-to-GB origin egress conversion.
What each symbol means
Worked substitution with the default inputs
The default proposal substantially reduces origin traffic but does not pay back the entered incremental platform fee.
Worked situations
Practical examples
- Raising hit rate from 75% to 90% shifts 18 million of 120 million monthly requests away from origin.
- With a $1,200 incremental platform fee, the default proposal costs more despite cutting origin request volume by 60%.
Better inputs
Useful tips
- Segment large objects, dynamic requests, and cacheable responses when their costs differ.
- Include cache invalidation and fill traffic if material.
- Compare latency, resilience, and origin capacity benefits alongside direct cost.
Before relying on the result
Limitations and common mistakes
- The model uses average response size and linear per-unit rates.
- Tiered pricing, minimum commitments, request classes, fill traffic, eviction, stale data, and engineering labor are excluded.
- A lower origin request count does not guarantee proportional server decommissioning.
Reference
Key terms
- Hit rate
- Share of eligible requests answered by the cache.
- Origin miss
- Request that reaches the origin service.
- Shifted request
- Request moving from origin to cache between the current and proposed cases.
Important note
Validate cache correctness, freshness, invalidation, security, privacy, failure behavior, and observed billing before production rollout.
Frequently asked questions
Why are savings negative in the default case?
Avoided origin compute and egress do not cover the entered $1,200 incremental cache platform cost.
Is hit rate based on bytes or requests?
This calculator uses request hit rate and one average origin response size; byte hit rate may tell a different story.
Does the model include CDN internet delivery?
No. Enter cache serving cost that reflects the applicable cache layer and add other delivery costs outside this model.