# Machine Availability Calculator

> Measure availability from a shift's records, or from MTBF and MTTR.

Page: https://freecalculator.tech/tools/machine-availability-calculator
Last reviewed: 2026-09-16

## Formula

Period method: Availability = (Planned production time − Downtime) ÷ Planned production time × 100; Reliability method: Availability = MTBF ÷ (MTBF + MTTR) × 100

- Period method: Availability = (Planned production time − Downtime) ÷ Planned production time × 100; Reliability method: Availability = MTBF ÷ (MTBF + MTTR) × 100.
- Inputs used: How do you want to measure availability?, Planned production time, Unplanned downtime inside that time, Mean time between failures (MTBF), Mean time to repair (MTTR).
- Edge handling: Planned production time is required.; Planned production time cannot be negative.; Planned production time must be no more than 1000000000000.; Unplanned downtime inside that time is required.; Unplanned downtime inside that time cannot be negative..

## Inputs

- How do you want to measure availability?
- Planned production time
- Unplanned downtime inside that time
- Mean time between failures (MTBF)
- Mean time to repair (MTTR)

## Worked example: Availability from a shift's own records

The reliability method is there when you have MTBF and MTTR instead; you choose which one you are using.
1. Start with How do you want to measure availability?: time, Planned production time: 480, Unplanned downtime inside that time: 47, Mean time between failures (MTBF): 0, Mean time to repair (MTTR): 0.
2. Apply the method: Period method: Availability = (Planned production time − Downtime) ÷ Planned production time × 100; Reliability method: Availability = MTBF ÷ (MTBF + MTTR) × 100.
3. The reliability method is there when you have MTBF and MTTR instead; you choose which one you are using.

## Common questions

### Where does this formula come from?

Availability as defined in the lean manufacturing guidance published by NIST MEP — run time as a share of planned production time; the reliability form expresses the same idea as mean time between failures over mean time between failures plus mean time to repair. See the source link on this page.

### What kind of calculation is this?

Two published ways of measuring availability. The user selects which one they are using and only that one's inputs are used.

### What are its limits?

Arithmetic over the figures entered — it cannot tell whether the measurements behind them are right. A measured result, an industry benchmark and an organisation's target are three different things; only the entered figures are used. Availability is one factor of overall equipment effectiveness; on its own it says nothing about speed or quality.

### How do I use the Machine Availability Calculator?

Enter the required values for How do you want to measure availability?, Planned production time, Unplanned downtime inside that time, Mean time between failures (MTBF), Mean time to repair (MTTR). 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 Machine Availability Calculator use?

Period method: Availability = (Planned production time − Downtime) ÷ Planned production time × 100; Reliability method: Availability = MTBF ÷ (MTBF + MTTR) × 100 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 Machine Availability 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.

## 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 machine availability calculator; it does not supply missing rates, rules, prices, dates, or assumptions for you.

## Sources

- National Institute of Standards and Technology, Manufacturing Extension Partnership — https://www.nist.gov/mep

## Cite this page

- APA: Free Calculator. (2026, September 16). Machine Availability Calculator. https://freecalculator.tech/tools/machine-availability-calculator
- MLA: "Machine Availability Calculator." Free Calculator, 16 Sept. 2026, https://freecalculator.tech/tools/machine-availability-calculator.
- Link: Machine Availability Calculator — Free Calculator, https://freecalculator.tech/tools/machine-availability-calculator