SLO Compliance Calculator
Compare the service level achieved with the objective you set.
In short
Formula: Achieved = Good events / Valid events; Gap = Achieved − SLO
What this calculator does
The good-events-over-valid-events ratio from the SRE workbook. The objective is an input; the calculator reports whether it was met and by how much, and never proposes an objective.
Use it to turn Requests that met the objective, Valid requests measured, Service level objective into a checked result you can compare, copy, or rerun with different assumptions.
The page shows the formula, a numeric worked example, and the assumptions that affect this professional & industry calculation.
Inputs and what they mean
- Requests that met the objective
- — Requests counted as good..
- Valid requests measured
- — All requests the objective is measured over..
- Service level objective
- — The objective your team agreed. Nothing is assumed about what it should be..
How to use it
- Enter your own figures — the calculator never fills in a rate, price or benchmark for you.
- Press Calculate to see the result.
- Read the formula, variables, assumptions and source below the result before you rely on it.
Formula
Achieved = Good events / Valid events; Gap = Achieved − SLO.
Inputs used: Requests that met the objective, Valid requests measured, Service level objective.
Edge handling: Requests that met the objective is required.; Requests that met the objective cannot be negative.; Requests that met the objective must be no more than 1000000000000.; Valid requests measured is required.; Valid requests measured cannot be negative..
Worked example
19,991,000 good out of 20,000,000 against a 99.9% objective
- Start with Requests that met the objective: 19991000, Valid requests measured: 20000000, Service level objective: 99.9.
- Apply the method: Achieved = Good events / Valid events; Gap = Achieved − SLO.
- Compares your measured level with the objective you entered.
Reading the result
The headline figure is the main answer. Any breakdown underneath shows the parts that make it up, so you can check the working and see what changes when you adjust an input.
Limitations and assumptions
- Inputs outside the supported range are rejected rather than forced into a result.
- The result depends on the values you enter for this slo compliance calculator; it does not supply missing rates, rules, prices, dates, or assumptions for you.
Reference: Google — Implementing SLOs
Last reviewed:
Common questions
Where does this formula come from?
Implementing SLOs — a service level objective is the share of good events among valid events (or of available time in the period); the error budget is the remainder that the objective permits. See the source link on this page.
What kind of calculation is this?
The achieved share of good events, compared with the objective the user entered. Check the formula, example, and limitations on this page before using the result for a real professional & industry decision.
What are its limits?
Arithmetic over the figures entered — it cannot tell whether the underlying monitoring, incident records or change records are complete. A mean over a short period, or over few events, is a weak description of behaviour. One ratio over a period; it does not show whether failures were concentrated in a short window.
How do I use the SLO Compliance Calculator?
Enter the required values for Requests that met the objective, Valid requests measured, Service level objective. The calculator applies the formula on this page and shows the main result with any supporting breakdown so you can check the arithmetic.
What formula does the SLO Compliance Calculator use?
Achieved = Good events / Valid events; Gap = Achieved − SLO The visible formula section above lists the calculation path and the edge cases the page handles, so the result can be checked without relying on the form alone. Check the formula, example, and limitations on this page before using the result for a real professional & industry decision.
Can the SLO Compliance Calculator be used for exact decisions?
Use it as a calculation aid, not as a substitute for checking the underlying rule, contract, policy, or professional advice that applies to your situation. When a result depends on local rules, personal details, prices, or dates, enter those values yourself and confirm them before acting.
Formula, source and verification
The achieved share of good events, compared with the objective the user entered.
The question it answers: How much error budget does our objective allow, how much is left, and did we meet the commitment in the agreement?
The formula
Achieved = Good events / Valid events; Gap = Achieved − SLO
- G — Good events
- (count). Requests that met the objective.
- V — Valid events
- (count). All requests the objective is measured over.
- SLO — Objective
- (%). The objective the user's team agreed.
Units: Counts in, percentages out.
What kind of calculation this is
Deterministic formula. The same inputs always give the same answer. The maths is fixed and does not depend on judgement.
Method
The good-events-over-valid-events ratio from the SRE workbook. The objective is an input; the calculator reports whether it was met and by how much, and never proposes an objective.
Assumptions built into the result
- Mathematical: The figures entered all cover the same measurement period.
- Mathematical: Incidents, changes and requests are counted consistently with the definition the team has written down.
- Mathematical: Good and valid events are counted by the same definition the objective uses.
Figures this calculator will never guess for you
- No target, benchmark, industry average or performance band is supplied for any figure.
- A definition is never presented as a goal: the availability formula is not an availability target, and the change failure rate formula is not an acceptable failure rate.
- No objective is suggested, defaulted or described as usual.
Limitations
- Arithmetic over the figures entered — it cannot tell whether the underlying monitoring, incident records or change records are complete.
- A mean over a short period, or over few events, is a weak description of behaviour.
- One ratio over a period; it does not show whether failures were concentrated in a short window.
Source and version
- Standard or reference
- Google SRE Workbook — Implementing SLOs — Google SRE (Implementing SLOs — a service level objective is the share of good events among valid events (or of available time in the period); the error budget is the remainder that the objective permits.)
- Published source
- Google — SRE Workbook
- Formula version
- Version 1
- Verification
- Reviewed against the cited source on
- How much weight the source carries
- Standards or government
- Applies to
- Currency
- The result is a ratio or index, so it does not depend on currency.
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