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Uptime / SLA Calculator

Convert an uptime percentage (SLA) into allowed downtime per year and month.

Inputs

Uptime %

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Saved Scenarios

— select 2+ to compare
Inputs updated · Results recalculated · Just now

Downtime/Year (minutes)

525.6

Downtime/Month (minutes)

43.80

Spark says

How it's calculated
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Formula

Downtime=(1−Uptime%100)×Minutes in PeriodDowntime = \left(1 - \dfrac{Uptime\%}{100}\right) \times Minutes\ in\ Period
Uptime\%
— The SLA percentage, e.g. 99.9

What is the Uptime / SLA Calculator?

Cloud and hosting providers advertise reliability as an uptime percentage — this calculator converts that into concrete allowed downtime, since small percentage differences translate to very different real-world outage budgets.

How to use it

  1. 1 Select the uptime percentage (SLA tier).

Worked examples

99.9% uptime

About 525.6 minutes (8.76 hours) of downtime allowed per year.

Try it

Real-life uses

  • Understanding what a vendor's SLA actually guarantees
  • Comparing hosting providers' reliability tiers

Frequently asked questions

Why does each extra '9' matter so much?

Each additional nine cuts allowed downtime by roughly 10x — going from 99.9% to 99.99% cuts yearly downtime from about 8.76 hours to under an hour.

calixo.cloud/developer/uptime-sla-calculator/ — free calculator, no signup required.