Uptime and SLA calculator
Enter an availability target to see how much downtime it leaves room for. Handy for writing an SLA, checking what a provider promises, or sizing an error budget.
Any value from 0 to 100, with as many decimals as you need.
Allowed downtime
- Downtime per day
- 1 min 26 s
- Downtime per week
- 10 min 5 s
- Downtime per month
- 43 min 50 s
- Downtime per quarter
- 2 h 11 min 29 s
- Downtime per year
- 8 h 45 min 57 s
Measured the way our status pages measure it, with a check every 5 minutes, 99.9% allows 8 failed checks out of the 8,766 in an average month.
Downtime for common SLA targets
| Uptime | Per day | Per week | Per month | Per quarter | Per year |
|---|---|---|---|---|---|
| 99%two nines | 14 min 24 s | 1 h 40 min 48 s | 7 h 18 min 17 s | 21 h 54 min 52 s | 3 days 15 h 39 min |
| 99.5% | 7 min 12 s | 50 min 24 s | 3 h 39 min 9 s | 10 h 57 min 26 s | 1 day 19 h 49 min |
| 99.9%three nines | 1 min 26 s | 10 min 5 s | 43 min 50 s | 2 h 11 min 29 s | 8 h 45 min 57 s |
| 99.95% | 43.2 s | 5 min 2 s | 21 min 55 s | 1 h 5 min 45 s | 4 h 22 min 58 s |
| 99.99%four nines | 8.6 s | 1 min | 4 min 23 s | 13 min 9 s | 52 min 36 s |
| 99.999%five nines | 864 ms | 6 s | 26.3 s | 1 min 19 s | 5 min 16 s |
Uptime and SLA questions
- How much downtime does 99.9% uptime allow?
- About 43 min 50 s a month, 10 min 5 s a week and 8 h 45 min 57 s a year. Put another way, the service may be unavailable for one minute in every thousand.
- What does "five nines" mean?
- An uptime of 99.999%, written with five 9s. It leaves room for about 5 min 16 s of downtime a year, or 26.3 s a month. Every extra nine cuts the allowed downtime by a factor of ten.
- How long is a month in this calculator?
- An average calendar month of 30.44 days, so that twelve months add up to a year of 365.2425 days. For a specific month, multiply the daily figure by its number of days: a 31-day month allows a little more downtime, February a little less.
- Does planned maintenance count against an SLA?
- That depends on the agreement. Many SLAs exclude maintenance announced in advance, and each one defines downtime in its own way. This calculator counts every second, so check your contract's definition before comparing.
- How is uptime measured on upordown.online?
- Each monitored service is checked every 5 minutes from EU (Falkenstein). Its uptime is the share of those scheduled checks that got an answer, shown for the last 24 hours and 30 days on its status page. Checks started by visitors are left out, because people check more often when something is already wrong.