ADC Health Score Calculator

Score an application delivery tier across availability, latency, errors, utilisation, SSL load and persistence, and name the weak spot.

Inputs

Pool member availability%

Average pool member utilisation%

p95 response timems

p95 response time targetms

5xx error rate%

SSL/TLS processing utilisation%

Persistence lookups that hit%

ADC Health Score

93.4

Rating

A — Excellent

Weakest Dimension

5xx error rate

Gap to a 90-Point Target

0.0%

Step by step

Values used
Pool member availability = 99.50 %; Average pool member utilisation = 55 %; p95 response time = 180 ms; p95 response time target = 200 ms; 5xx error rate = 0.4000 %; SSL/TLS processing utilisation = 40 %; Persistence lookups that hit = 96 %
ADC Health Score
score = 0.30×availability + 0.20×latency + 0.20×errors + 0.10×utilisation + 0.10×SSL headroom + 0.10×persistence hit rate, each normalised to 0–100.
ADC Health Score
= 93.4
Rating
= A — Excellent
Weakest Dimension
= 5xx error rate
Gap to a 90-Point Target
= 0.0

How it works

Each metric is normalised onto a 0–100 subscore, inverting the ones where lower is better and penalising utilisation in both directions since an idle pool is wasted spend and a saturated one has no failover room. The weights put availability and latency first because those are what a user experiences. An ADC tier can be green on every individual dashboard and still be one node failure from an outage, so a single weighted score with the weakest dimension named is what makes the next piece of work obvious.

Formula

ADC Health Score

score = 0.30×availability + 0.20×latency + 0.20×errors + 0.10×utilisation + 0.10×SSL headroom + 0.10×persistence hit rate, each normalised to 0–100.

availS: Availability rescaled so 95% scores zero and 100% scores full marks
utilS: Peaks at 55% utilisation — both idle and saturated pools lose points

Frequently Asked Questions

How is ADC Health Score calculated?

score = 0.30×availability + 0.20×latency + 0.20×errors + 0.10×utilisation + 0.10×SSL headroom + 0.10×persistence hit rate, each normalised to 0–100. Each metric is normalised onto a 0–100 subscore, inverting the ones where lower is better and penalising utilisation in both directions since an idle pool is wasted spend and a saturated one has no failover room. The weights put availability and latency first because those are what a user experiences.

Why does ADC Health Score matter?

An ADC tier can be green on every individual dashboard and still be one node failure from an outage, so a single weighted score with the weakest dimension named is what makes the next piece of work obvious.

What values do I need to enter?

This calculator takes 7 inputs: Pool member availability, Average pool member utilisation, p95 response time, p95 response time target, 5xx error rate, SSL/TLS processing utilisation, Persistence lookups that hit. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

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