SLO Compliance Calculator
Check whether current SLI performance is meeting your defined SLO target.
About SLO Compliance Calculator
SLO compliance measures how your actual success rate compares to a committed target: actual_slo = (total − failed) ÷ total × 100. Burn rate expresses this as a multiple of your allowed error budget consumption rate — a burn rate of 1x means you're consuming your error budget exactly on pace to exhaust it by the end of the period; a burn rate of 10x means you'd exhaust a 30-day budget in 3 days.
Formulas
Actual SLO
actualSLO = ((totalRequests - failedRequests) / totalRequests) × 100
- T
- Total requests in the measurement window
- F
- Failed requests
- S_a
- Actual SLO percentage
Burn rate
burnRate = actualErrorRate / allowedErrorRate
- e_a
- Actual error rate percentage
- e_t
- Allowed error rate (100 - SLO target)%
- B
- Burn rate (1× = on pace, >1× = over budget)
Worked example
With the default values below, SLO Compliance Calculator returns Actual SLO of 99.8800%. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Total Requestsaccepts 1–1,000,000,000,000 requests
- 1,000,000 requests
- Failed Requestsaccepts 0–1,000,000,000,000 requests
- 1,200 requests
- SLO Targetaccepts 0–100 %
- 99.9 %
Results
- Actual SLO
- 99.8800%
- Burn Rate
- 1.20 ×
- SLO Compliant
- false
- Margin vs Target
- -0.0200 pp
- Allowed Failed Requests
- 1,000 requests
Step by step
- 1Successful requests= 998,800
- 2Actual SLO: successful ÷ total= 99.8800%
- 3Burn rate: actual error rate ÷ allowed error rate= 1.20×
Assumptions and limits
- The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
What does a burn rate greater than 1 mean?
It means your current error rate exceeds what's sustainable to stay within the SLO for the full measurement period — if it continues at this rate, you'll breach your error budget before the period ends.
How is burn rate different from actual SLO percentage?
Actual SLO percentage is a point-in-time snapshot of overall compliance; burn rate expresses velocity — how fast you're using up the allowed error budget relative to a sustainable pace.
Should I alert on SLO percentage or burn rate?
Most mature SRE practices alert on burn rate (e.g. multi-window multi-burn-rate alerts) because it catches fast-developing problems early, well before the cumulative SLO percentage itself would breach.
What counts as a 'failed' request for SLI purposes?
This depends on your SLI definition — commonly 5xx errors, requests exceeding a latency threshold, or business-logic failures. Be consistent about the definition across your SLO reporting.