Error Budget Burn Rate

A classic SRE multi-window alerting signal. Burn rate 1 means you are on track to exhaust the budget exactly at period end; above 1 means overspending.

Burn rate = (error budget consumed %) ÷ (percent of SLO period elapsed).

Tip: Keep “Error Budget Consumed (%)” and “Period Elapsed (%)” on the same basis (currency, tax treatment, and time period) before you calculate.

Cluster: DevOps hub · Deployment frequency · Software Testing hub · Percentage guide

Burn rate compares how fast you are spending the error budget to how far you are through the SLO window.

Enter error budget consumed % and percent of the period that has elapsed.

Share of allowed downtime already used
Percent of the SLO window that has passed

Burn Rate

Understanding Error Budget Burn Rate

How we calculate. Burn rate = (error budget consumed %) ÷ (percent of SLO period elapsed). See our methodology and accuracy policy .

Real-world scenario: A typical Error Budget Burn Rate case uses error budget consumed (%) 40 and period elapsed (%) 20. Enter the same figures below to reproduce the worked path.

What is Error Budget Burn Rate?

A classic SRE multi-window alerting signal. Burn rate 1 means you are on track to exhaust the budget exactly at period end; above 1 means overspending.

  • Consumed % from your SLO math
  • Elapsed % = time passed ÷ period × 100
  • Alert on sustained high burn

The Formula

Error Budget Burn Rate
Burn rate = Consumed % ÷ Period elapsed %

Worked Example

Scenario: Consumed 40% of budget; 20% of the month has elapsed.
Step 1: Burn rate = 40 ÷ 20 = 2
Answer: Burn rate is 2× (spending twice as fast as a linear budget).

Common Use Cases

  • Page policies: multi-window burn alerts
  • Incident response: stop the bleed
  • SLO coaching: early-month risk

Pro Tips

  • Use short and long windows together
  • Recalculate after major incidents
  • Pair with remaining %
ScenarioWhen to use
Percent of a numberFinding a part of a whole (tax, tip, score)
Percent changeComparing old vs new values

Limitations: Error Budget Burn Rate results are educational DevOps/SRE/FinOps planning aids—not SLAs, billing guarantees, or operational policy. Confirm definitions with your platform and finance teams.

Common mistakes

  • Swapping part and whole: The denominator must be the full total, not a subset.
  • Rounding too early: Carry extra decimal places through multi-step work before rounding the final percent.
  • Mixing percent and decimal forms: Enter rates in the format the calculator labels expect.

The worked example for error budget burn rate was verified with the calculator form on this page—enter the same values to confirm the result.

When to use this calculator

  • Use this page when your wording matches error budget burn rate and the form labels on screen.
  • Use percent of a number for “what is X% of Y?” problems.
  • Use number is what percent when you know part and whole and need the percent.

Still unsure about error budget burn rate? Start with the quick answer above, then open the linked calculator that matches your wording.

Frequently Asked Questions

How do I use this error budget burn rate calculator?

For error budget burn rate, enter the values labeled on the form, then press Calculate. Compare the result to the worked example on this page.

What formula does this page use?

See the quick answer and formula box above for error budget burn rate—the same percentage calculator expression is applied to your inputs.

What if my result looks wrong?

When checking error budget burn rate, re-check part vs whole (or rate vs base), rounding, and whether percents were entered as 25 rather than 0.25 when the form expects percents.

Authoritative References

For SRE and FinOps definitions, consult: