MTBF MTTR Availability Calculator
Calculate steady-state availability and expected downtime in an entered calendar from mean up and repair times.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Treat the means as alternating up and down intervals, using MTBF as mean up-time rather than total renewal-cycle time.
Availability=MTBF/(MTBF+MTTR); downtime=calendar×(1−availability)
Worked example
Mean up-time 1000 h and mean repair time 2 h give availability 99.8003992%; over 365 days expected downtime is about 17.4850299 h.
Assumptions and input details
Long-run alternating renewal model, not an uptime guarantee or SLA compliance result. Common-cause failures, planned maintenance, startup state and finite-horizon transient probabilities are excluded.
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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