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SLA calculator
How long can a service be down without breaching its SLA? For example, 99.9% = 43 min 50 s per month.
Most common SLA levels
| Availability | Per day | Per week | Per month | Per year |
|---|---|---|---|---|
| 99 % | 14 min 24 s | 1 h 40 min | 7 h 18 min | 3 d 15 h |
| 99.5 % | 7 min 12 s | 50 min 24 s | 3 h 39 min | 1 d 19 h |
| 99.9 % | 1 min 26 s | 10 min 5 s | 43 min 50 s | 8 h 45 min |
| 99.95 % | 43 s | 5 min 2 s | 21 min 55 s | 4 h 22 min |
| 99.99 % | 9 s | 1 min | 4 min 23 s | 52 min 36 s |
| 99.999 % | 1 s | 6 s | 26 s | 5 min 16 s |
Month = year / 12 (30.44 days). Total downtime each level allows, not counting scheduled maintenance.
What is an SLA (service level agreement)?
An SLA is the commitment a provider signs about its service: almost always a minimum monthly availability percentage and compensation if it's missed.
The gap between 99.9% and 99.99% looks tiny, but it's the difference between about 43 minutes and about 4 minutes of allowed downtime a month.
To know whether your provider delivered, you need to measure from the outside with clear rules: what counts as downtime, how maintenance is treated, and what happens when measurement failed.
Measure your real availability and prove it
We check your services every minute and each month generate the SLA report with availability, outages, their causes and excluded maintenance.
Frequently asked questions
What does SLA mean?
Service Level Agreement. It defines how available a service must be and what happens if it isn't.
What's the difference between SLA, SLO and SLI?
The SLA is what's promised to the customer; the SLO is the internal target to meet it with margin; the SLI is the real measurement (for example, the month's availability percentage).
How is SLA availability calculated?
Time up divided by time measured, as a percentage. A good report excludes scheduled maintenance and periods when measurement wasn't possible.
How much downtime does a 99.9% SLA allow?
1 min 26 s per day, 43 min 50 s per month and 8 h 45 min per year.
How is availability calculated?
Availability = (total time − downtime) / total time × 100. Scheduled maintenance is usually subtracted from total time.
What happens if the monitoring itself fails?
A good report separates the periods that couldn't be measured from real outages, so your service isn't blamed for a monitoring problem. Our reports do this.