Error Budget Consumed

SRE planning metric. Over 100% means you have exhausted the budget for the period.

Allowed downtime = period × (1 − SLO/100); consumed % = downtime ÷ allowed × 100.

Tip: Keep “SLO (%)” and “Period Length” on the same basis (period, units, and population) before calculating Error Budget Consumed.

Cluster: DevOps hub · Software Testing hub · Percentage guide

Error budget consumed shows how much of the allowed unreliability for an SLO you’ve used.

Enter SLO (%), period length, and downtime in the same time unit as the period.

%
Availability SLO target
Period duration (e.g. minutes)
Observed downtime (same unit)

Error Budget Consumed

Understanding Error Budget Consumed

How we calculate. Allowed downtime = period × (1 − SLO/100); consumed % = downtime ÷ allowed × 100. The form uses the same arithmetic as the worked examples on this page. See our methodology and accuracy policy.

Real-world scenario: A typical Error Budget Consumed case uses slo (%) 99.9 and period length 43200. Enter the same figures below to reproduce the worked path.

What is Error Budget Consumed?

SRE planning metric. Over 100% means you have exhausted the budget for the period.

  • SLO is availability target (e.g. 99.9)
  • Period and downtime same unit
  • >100% = budget exhausted

The Formula

Error Budget Consumed
Consumed % = Downtime ÷ (Period × (1 − SLO/100)) × 100

Worked Example

Scenario: SLO 99.9%, period 43,200 minutes (30 days), downtime 30 minutes.
Step 1: Allowed = 43200 × (1 − 0.999) = 43.2 minutes
Step 2: Consumed = (30 ÷ 43.2) × 100 ≈ 69.44%
Answer: Error budget consumed is about 69.44%.

Common Use Cases

  • Release freezes: budget gates
  • SRE reviews: burn rate narrative
  • Multi-service SLOs: compare burn

Pro Tips

  • Align downtime with SLO filter
  • Track remaining % as 100 − consumed
  • Use rolling windows when contracts require

Limitations: Error Budget Consumed results are educational DevOps/FinOps planning aids—not SLAs or billing guarantees. Confirm definitions with your platform and finance policies.

FAQ

What if SLO is 100%?

Allowed downtime is 0—any downtime means infinite/undefined budget math. Use SLO < 100.

Minutes or hours?

Any unit works if period and downtime match.

Authoritative References

For DORA and FinOps definitions, consult: