ADC Health Score Calculator

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

About ADC Health Score Calculator

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

Worked example

With the default values below, ADC Health Score Calculator returns ADC Health Score of 93.4. Change any input above and every figure here is recalculated in your browser.

Inputs used

Pool member availabilityaccepts 0–100 %: 99.5 %
Average pool member utilisationaccepts 0–100 %: 55 %
p95 response timeaccepts 0–600,000 ms: 180 ms
p95 response time targetaccepts 1–600,000 ms: 200 ms
5xx error rateaccepts 0–100 %: 0.4 %
SSL/TLS processing utilisationaccepts 0–100 %: 40 %
Persistence lookups that hitaccepts 0–100 %: 96 %

Results

ADC Health Score: 93.4
Rating: A — Excellent
Weakest Dimension: 5xx error rate
Gap to a 90-Point Target: 0.0%

Step by step

1Values used
2ADC Health Score
3ADC Health Score= 93.4
4Rating= A — Excellent
5Weakest Dimension= 5xx error rate
6Gap to a 90-Point Target= 0.0

Assumptions and limits

The result is derived only from the 7 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 1 decimal place, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

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.