How this calculator works
Enter slo target (%), monthly requests, period days. CalcStack applies the displayed formula and reports each intermediate planning value with the units shown.
Formula / method
Error budget requests = total requests × (1 − SLO); downtime = period minutes × (1 − SLO)
Worked example
A 99.9% 30-day SLO over 10M requests permits 10,000 failed requests and 43.2 minutes downtime.
Assumptions and limitations
Every request is weighted equally and the period contains 24-hour days.
Partial outages, excluded maintenance, latency SLOs and multi-window burn rates are not included.