Measure API Error Budget Consumption and Burn Rate

How to Use This Tool

Compare observed failures with the SLO allowance and elapsed share of the window. An error count has no urgency until it is compared with both the SLO allowance and how much of the window elapsed.

Why Error Budget Burn needs more than a raw total

Burn rate above one consumes budget faster than the sustainable pace. For this page, the useful comparison is normalized budget burn rate, not whichever input happens to be largest. The Error Budget Burn result answers the decision in the heading and should not be reused as a score for a different workflow.

The exact Error Budget Burn formula

Burn rate equals fraction of error budget consumed divided by fraction of window elapsed. The visible fields are Requests in observed period, Availability SLO, Observed errors, SLO window and Elapsed period. For Error Budget Burn, read each printed unit before entry and make the values describe one transaction, cohort or reporting window. If those scopes differ, the displayed normalized budget burn rate may be arithmetically valid but operationally meaningless.

Interpreting normalized budget burn rate

Use multi-window alerts and incident context before freezing releases from one short spike. The ten-percent comparison is deliberately narrow: it tests the influence of requests in observed period and is neither a forecast nor a confidence interval. Preserve the values used, their dates and the resulting decision so a later reviewer can reproduce why Error Budget Burn supported the choice.

What this Error Budget Burn model leaves out

Request weighting, exclusions and rolling-window query semantics must match the service SLO. That is where Error Budget Burn stops being trustworthy. If an excluded factor could reverse normalized budget burn rate, extend the model explicitly or use the authoritative account system instead of hiding the factor inside an unexplained adjustment.

Evidence and independent verification

The reference reviewed for Error Budget Burn is Google SRE — Alerting on SLOs. Google SRE — Alerting on SLOs supports the named definition or rule but does not supply private values for normalized budget burn rate. Before acting on the result, reconcile the worked example with the relevant dashboard, invoice, export or measurement.

Private, reproducible calculation

Error Budget Burn runs its arithmetic in the current browser tab and requests no login or API key. That keeps the Error Budget Burn inputs away from the site's calculation server, while leaving the user responsible for detecting stale data or a changed platform rule. When an assumption changes, reopen Google SRE — Alerting on SLOs and rerun the saved Error Budget Burn scenario.