Service SLA Error Budget Calculator

Method and input definitions

Allowed downtime minutes = period hours × 60 × (100 − target percent) ÷ 100. Remaining budget = allowed downtime − consumed downtime. A period is entered directly in hours, so month length is never silently assumed.

Worked example

A 720-hour period at a 99.9% availability target allows 720 × 60 × 0.001 = 43.2 minutes. If 18 minutes are consumed, 25.2 minutes remain.

Assumptions and limits

Availability target and consumed downtime must use the same policy and period boundaries. Exclusions, maintenance windows, and measurement methodology depend on the service agreement and are not inferred.

Inputs are bounded to finite values shown in the form. Displayed results are rounded for readability (probability percentages and proportion fractions to four, other measures to two decimal places); whole-count outputs remain exact. A changed field clears a prior result so an outdated estimate is not presented as current.

References and related tools

Google Site Reliability Engineering, “Embracing Risk” (2016; written by Marc Alvidrez) discusses availability targets and acceptable unplanned downtime. The time-budget arithmetic here does not define an SLA or its exclusions.

• Deadline Countdown
• Task Time Estimator

Browse all productivity and time calculators.