Reliability · SRE
SLO burn rate calculator.
Burn rate is how fast you consume error budget compared with the pace that would use it up exactly at the end of the window.
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Result
Enter the values above.
What is an SLO burn rate?
The Google SRE Workbook defines burn rate as how fast, relative to the SLO, a service consumes the error budget. A burn rate of 1 uses exactly the whole budget by the end of the window; 2 uses it in half the time. Burn rate = observed error rate / allowed error rate, where the allowed rate is 100% minus the SLO. The workbook's example is a burn rate of 2 over a 30-day window exhausting the budget in 15 days.
Worked example. A 99.9% SLO allows 0.1% errors. A steady 0.5% error rate is a burn rate of 5, so a full budget lasts 30 / 5 = 6 days.
Frequently asked questions
What does a burn rate of 1 mean?
You are consuming budget at exactly the pace that finishes it at the end of the window.
How do I calculate time to exhaustion?
Window length divided by burn rate, scaled by the share of budget remaining. At burn rate 2 over 30 days, 15 days.
What burn rate should page someone?
The workbook example pages at 14.4 over one hour and 6 over six hours for a 99.9% SLO over 30 days. See the multi-window alert calculator.
Is this the instantaneous or average error rate?
Whatever you enter. Use the error rate over the window you care about, such as the last hour.
Sources
Checked
Formulas follow the sources above. Periods use a 30-day month and a 365-day year. Runs entirely in your browser; nothing you type is sent or stored.
Scope
Planning estimates only. Your SLA contract defines its own measurement window, exclusions and remedies, and those override these generic figures. Theoretical availability assumes independent failures.