Downtime Minutes Per Year Calculator

Work out downtime minutes per year instantly with clear inputs, formula shown and shareable results.

About Downtime Minutes Per Year Calculator

Total annual downtime is planned plus unplanned minutes, and the year contains 525,600 minutes. Planned maintenance often dominates, which is why SLAs usually exclude it — and why zero-downtime deployment techniques deliver more measured availability than any amount of hardware redundancy.

Formula

Annual availability

downtime = planned windows x minutes + incidents x minutes; availability = 1 - downtime / 525600

Worked example

With the default values below, Downtime Minutes Per Year Calculator returns Total downtime per year of 960. Change any input above and every figure here is recalculated in your browser.

Inputs used

Planned maintenance windows per yearminimum 0: 12
Minutes per planned windowminimum 0 min: 45 min
Unplanned incidents per yearminimum 0: 6
Minutes per unplanned incidentminimum 0 min: 70 min

Results

Total downtime per year: 960 min
Resulting availability: 99.8174%
Unplanned downtime: 420 min
Nines achieved: 2.74

Step by step

1Values used
2Annual availability
3Total downtime per year= 960 min
4Resulting availability= 99.8174
5Unplanned downtime= 420 min
6Nines achieved= 2.74

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 or fees or charges into account.
Figures are rounded for display to 4 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 planned maintenance count against availability?

Commercially it is usually excluded, but users experience it as downtime. Tracking both figures avoids a comfortable SLA number that does not match user perception.

How is planned downtime eliminated?

Rolling upgrades, blue-green deployment and backwards-compatible schema migrations. All require the application to tolerate running two versions at once.