SLO Error Budget Burn Rate: Azure Zone Outage Math

If your service has a 99.99% SLO and Azure drops a zone for 15 minutes, here's exactly how to calculate the error budget burn rate before your next SRE interview. You'll learn: How to derive total monthly error budget from a 99.99% SLO (~4.38 minutes/month) Why a 15-minute outage consumes roughly 3.4x your entire monthly budget — and how to show that math The burn rate formula interviewers expect: burn rate = error rate / (1 − SLO target) How fast vs. slow burn rates map to alerting windows in Google's SRE workbook approach Common gotchas: partial zone failures, dependency blame, and how to frame mitigation in your answer Keywords: SLO error budget burn rate, Azure availability zone outage, SRE interview questions, error budget calculation, 99.99 SLO math 🎧 Listen, then go deeper — DevOps & Cloud interview-prep ebooks at DevOpsInterview.Cloud