Patch Compliance Percentage Calculator

Work out patch compliance percentage instantly with clear inputs, formula shown and shareable results.

About Patch Compliance Percentage Calculator

Patch compliance as a single percentage hides risk concentration: 87 percent compliance sounds tolerable until you notice 38 hosts are missing critical patches. Severity-weighted reporting is what makes the metric actionable, because remediating those 38 matters far more than moving the headline figure by a few points.

Formula

Compliance

compliance = fully patched / hosts; hosts to remediate = ceil(hosts x target) - fully patched

Worked example

With the default values below, Patch Compliance Percentage Calculator returns Patch compliance of 87.00%. Change any input above and every figure here is recalculated in your browser.

Inputs used

Hosts in scopeminimum 1: 1,200
Hosts fully patchedminimum 0: 1,044
Hosts missing critical patchesminimum 0: 38
Compliance targetaccepts 1–100 %: 95 %

Results

Patch compliance: 87.00%
Hosts to patch to reach the target: 96
Hosts missing critical patches: 38
Status: Critical patches outstanding on 38 hosts - remediate before addressing the overall percentage

Step by step

1Values used
2Compliance
3Patch compliance= 87.00
4Hosts to patch to reach the target= 96
5Hosts missing critical patches= 38
6Status= Critical patches outstanding on 38 hosts - remediate before addressing the overall percentage

Assumptions and limits

The result is derived only from the 4 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 2 decimal places, 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

Should compliance be measured per host or per patch?

Both. Per host tells you coverage; per patch tells you whether one problematic update is stuck everywhere, which points at a packaging or dependency issue.

How are persistently unpatched hosts handled?

Investigate individually. They are usually appliances, systems with change freezes, or hosts the patching agent cannot reach — each needs a different remedy.