SRE Calculator
Availability nines, error budgets, burn rates, and SLO calculations
Availability (Nines) Calculator
Enter an uptime percentage to see the allowed downtime per period.
% uptime
Nines Quick Reference
| Availability | Nines | Downtime/Year | Downtime/Month |
|---|---|---|---|
| 90% | One nine | 36.5 days | 72 hours |
| 99% | Two nines | 3.65 days | 7.31 hours |
| 99.9% | Three nines | 8.77 hours | 43.83 min |
| 99.95% | Three and a half | 4.38 hours | 21.92 min |
| 99.99% | Four nines | 52.6 min | 4.38 min |
| 99.999% | Five nines | 5.26 min | 26.3 sec |
| 99.9999% | Six nines | 31.56 sec | 2.63 sec |
Error Budget Calculator
Given your SLO and time window, see how much error budget you have and how much remains.
Burn Rate Calculator
At the current error rate, how fast are you burning through your error budget?
Percentile (P99/P95/P50) Calculator
Enter latency values (one per line or comma-separated) to calculate percentiles.
About SRE Calculations
Site Reliability Engineering (SRE) uses Service Level Objectives (SLOs) to define reliability targets. The error budget is the allowed amount of unreliability: 100% - SLO = error budget.
Burn rate measures how fast you consume your error budget relative to the window. A burn rate of 1.0 means you will exactly exhaust your budget by the end of the window. A burn rate above 1.0 means you are on track to exceed your budget before the window ends.
Percentile latencies (P50, P90, P95, P99) show the value below which a given percentage of observations fall. P99 = 200ms means 99% of requests completed in 200ms or less.