Uptime SLA Calculator
Convert an availability target into the downtime budget you can spend per period.
Availability
99.900%
Nines
3
Down / year
8h 45m
Down / day
1m 26s
Uptime 99.9000% · Downtime 0.1000%
Allowed downtime
Daily1m 26s
Weekly10m 4s
Monthly43m 49s
Quarterly2h 11m
Yearly8h 45m
How this simulator works
Turn an availability target into the concrete downtime budget you are allowed per day, week, month, and year — the language SREs and contracts actually use.
Nines of availability
- 99% — two nines — ~3.65 days down per year.
- 99.9% — three nines — ~8h 46m per year.
- 99.99% — four nines — ~52m per year.
- 99.999% — five nines — ~5m per year (often the practical ceiling).
Using the budget
Each nine you add shrinks the yearly downtime budget by 10×. Set an error budget from allowed downtime, then trade it against feature velocity and incident response.