Free tools for people who look after websites
An uptime and SLA calculator that works in your browser, and a table of the downtime each SLA allows.
Uptime and SLA calculator
Type an uptime percentage to see how much downtime it allows. Or type the minutes a site was down in 30 days to see its uptime.
Downtime allowed by the target
- Per day
- 1 min 26 s
- Per week
- 10 min 5 s
- Per 30 days
- 43 min 12 s
- Per year
- 8 h 45 min
- Uptime with those minutes down
- 99.9004%
Downtime allowed by common SLAs
| Uptime | Per day | Per week | Per 30 days | Per year |
|---|---|---|---|---|
| 99% | 14 min 24 s | 1 h 40 min | 7 h 12 min | 3 d 15 h |
| 99.5% | 7 min 12 s | 50 min 24 s | 3 h 36 min | 1 d 19 h |
| 99.9% | 1 min 26 s | 10 min 5 s | 43 min 12 s | 8 h 45 min |
| 99.95% | 43 s | 5 min 2 s | 21 min 36 s | 4 h 22 min |
| 99.99% | 9 s | 1 min | 4 min 19 s | 52 min 34 s |
| 99.999% | 1 s | 6 s | 26 s | 5 min 15 s |
Is the site up? Check any address.
One check from our server, with no account: the answer and its speed, the SSL certificate and when the domain expires.
- HTTP status and response time
- Certificate issuer, validity and days left
- Domain expiry date from the registry, where it is published
Questions about uptime and SLAs
How much downtime is 99.9% uptime?
About 43 minutes in 30 days, 8 hours 45 minutes in a year and 1 minute 26 seconds a day.
Why 30 days and not a calendar month?
Months have 28 to 31 days. The calculator uses 30 days, the same window the SLA target on the platform compares with.
Do maintenance windows count as downtime?
In SitePing they do not: during a maintenance window the site is not checked and those minutes do not count against uptime. Check what your contract with the client says.
Does the calculator send what I type anywhere?
No. It works out the numbers in your browser.
Try SitePing on your client sites.
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- Every Complete feature except backups
- Up to 10 sites
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