Tools
Maintenance calculators
22 single-purpose calculators for maintenance, reliability, inventory and safety metrics. Each one shows its formula, states which definition it uses, and works out of a browser with nothing to sign up for.
Reliability and uptime
How much of the time your equipment is running, and what it costs when it is not.
OEE
OEE = Availability × Performance × Quality
Overall Equipment Effectiveness is the share of planned production time that was genuinely productive.
Availability
Availability = (Planned production time − Unplanned downtime) ÷ Planned production time × 100
Availability is the share of planned production time that the asset was actually able to run.
Performance rate
Performance = (Ideal cycle time × Total units) ÷ Run time × 100
Performance is the share of the theoretical maximum rate you actually achieved while the asset was running.
Quality rate
Quality = Good units ÷ Total units produced × 100
Quality is the share of units produced that met specification first time.
MTBF
MTBF = Total operating hours ÷ Number of failures
Mean Time Between Failures is the average operating time between one unplanned failure and the next.
MTTR
MTTR = Total repair time ÷ Number of repairs
Mean Time To Repair is the average time it takes to restore a failed asset to service.
Downtime percentage
Downtime % = Downtime hours ÷ Total hours in period × 100
Downtime percentage is the share of a period the asset was unavailable.
Cost of downtime
Downtime cost = Downtime hours × [(Lost units per hour × Contribution margin per unit) + (Idle staff × Hourly labor rate)]
The cost of downtime is lost contribution margin plus the labor you paid for regardless.
Maintenance program
Whether the work you planned is the work that actually happened.
PM compliance
PM compliance = PMs completed on time ÷ PMs scheduled × 100
PM compliance is the share of preventive maintenance that got done inside its window.
Schedule compliance
Schedule compliance = Work orders completed as scheduled ÷ Work orders scheduled × 100
Schedule compliance is the share of the work you planned for a period that actually got done in that period.
Planned maintenance %
PMP = Planned maintenance hours ÷ Total maintenance hours × 100
Planned maintenance percentage is the share of your maintenance hours that were planned rather than reactive.
Maintenance backlog
Backlog weeks = Outstanding work hours ÷ (Technicians × Available hours per technician per week)
Backlog measured in weeks tells you how long the outstanding work would take if no new work arrived.
Wrench time
Wrench time = Hands-on tool time ÷ Total paid time × 100
Wrench time is the share of a paid shift a technician spends with hands on the asset.
Maintenance cost as % of RAV
Maintenance cost % of RAV = Annual maintenance cost ÷ Replacement asset value × 100
Maintenance cost as a percentage of replacement asset value is the standard way to compare maintenance spend between sites of different sizes.
Parts and inventory
How much stock to hold, when to reorder, and how fast it moves.
Reorder point
Reorder point = (Average daily usage × Lead time in days) + Safety stock
The reorder point is the stock level at which you place the next order.
Safety stock
Safety stock = (Max daily usage × Max lead time) − (Average daily usage × Average lead time)
Safety stock is the buffer that covers you when usage runs hot and the supplier runs late at the same time.
EOQ
EOQ = √( (2 × Annual demand × Cost per order) ÷ Annual holding cost per unit )
Economic order quantity is the order size where the cost of ordering and the cost of holding stock are balanced.
Inventory turnover
Inventory turnover = Value of parts consumed ÷ Average inventory value
Inventory turnover is how many times you consume and replace the value of your storeroom in a year.
Safety and compliance
The OSHA-defined incident rates you report on.
TRIR
TRIR = (Recordable cases × 200,000) ÷ Total hours worked
Total Recordable Incident Rate is the number of OSHA recordable cases you would expect per 100 full-time workers per year.
DART rate
DART = (DART cases × 200,000) ÷ Total hours worked
The DART rate counts only the recordable cases serious enough to keep someone off their normal job: days away from work, restricted duty, or a transfer to different work.
LTIFR
LTIFR = (Lost time injuries × 1,000,000) ÷ Total hours worked
Lost Time Injury Frequency Rate is the number of injuries causing lost time per million hours worked.
Field service
How efficiently work gets closed out in the field.
About these calculators
Are these calculators free to use?
Yes. There is no sign-up, no email gate and no limit. Every calculation runs in your browser, and nothing you type is sent anywhere.
Can I share a result with someone else?
Yes. Every calculator writes your inputs into the page URL as you type, so copying the link shares the numbers along with the result. Useful when you are putting a case to a manager who wants to change one of the assumptions.
Which definition of each formula do you use?
The prevailing published definition, stated on each page above the inputs, along with any constant the formula depends on and why it is that value.
Some metrics have more than one accepted definition. MTTR can include parts waiting time or exclude it, and LTIFR can be quoted against a million hours or against 200,000. Those pages say which definition is used and how to convert, because quoting one definition against another is how two sites end up comparing numbers that were never comparable.
Do I need UpKeep to use these?
No. They are standalone calculators and they work with numbers from any source, including a spreadsheet or a paper log. UpKeep is useful because it records the hours, failures and completions these formulas need, so the metric becomes a report rather than a monthly data-gathering exercise.
Let the numbers keep themselves
Every figure on these pages comes from work orders, run hours and failure records. UpKeep captures those as the work happens, so the metric is a report you open rather than a spreadsheet someone rebuilds each month.