Uptime and SLA calculator
Enter an availability target and see how much downtime it allows per day, week, month, quarter and year. Add dependencies to see how the nines erode when services depend on each other.
- Downtime per year
- 8 h 46 min
- Downtime per month
- 43 min 12 s
- Downtime per day
- 1 min 26 s
| Period | At 99.9% | Combined 99.700% |
|---|---|---|
| Day | 1 min 26 s | 4 min 19 s |
| Week | 10 min 5 s | 30 min 13 s |
| Month (30 days) | 43 min 12 s | 2 h 9 min |
| Quarter | 2 h 10 min | 6 h 28 min |
| Year | 8 h 46 min | 1 d 2 h |
| Nines | Per year | Per month |
|---|---|---|
| 90% | 36 d 12 h | 3 d 0 h |
| 95% | 18 d 6 h | 1 d 12 h |
| 99% | 3 d 16 h | 7 h 12 min |
| 99.5% | 1 d 20 h | 3 h 36 min |
| 99.9% | 8 h 46 min | 43 min 12 s |
| 99.95% | 4 h 23 min | 21 min 36 s |
| 99.99% | 52 min 34 s | 4 min 19 s |
| 99.999% | 5 min 15 s | 25.9 s |
Everything runs in your browser; nothing you type is sent anywhere.
How to use it
- Enter your uptime or SLA target as a percentage, for example 99.9.
- Read the allowed downtime for each period in the table.
- Set the number of serial dependencies to see the combined availability if each one meets the same target.
Frequently asked questions
How much downtime is 99.9% uptime?
About 8 hours 46 minutes per year, 43 minutes per 30-day month, or 1 minute 26 seconds per day.
What does five nines mean?
99.999% availability, roughly 5 minutes 15 seconds of downtime per year. It usually requires redundancy across regions and automated failover.
Why is my combined availability lower than each service's?
When a request needs several services in series, availabilities multiply. Five services at 99.9% give about 99.5% overall.
Is an SLA the same as an SLO?
No. An SLA is a contract with consequences, usually credits. An SLO is your internal target, which should be stricter than the SLA you promise.
Made by compiler.dev, faster GitHub Actions runners. More free tools.
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