How do you calculate mean time between maintenance?

Divide total operating time by the total number of maintenance actions. For 7,200 operating hours and 30 actions, MTBM = 7,200 ÷ 30 = 240 hours per action.

What is the difference between MTBM and MTBF?

MTBF counts only failures (corrective events), while MTBM counts every maintenance action including preventive and inspection tasks. MTBM is therefore always lower than or equal to MTBF for the same asset.

What is a good MTBM value?

There is no universal number; it depends on asset type. The goal is a rising trend. An MTBM of 240 hours means roughly one maintenance touch every 10 days of continuous run time.

What is the normalization factor for?

It converts the base hours-per-action into another basis, such as per duty cycle or per shift, or applies a fleet correction. Leaving it at 1 reports raw hours per action.

How can I increase MTBM?

Eliminate recurring failure modes through root cause analysis, optimize over-frequent PM intervals, and design out maintenance with better seals, filters, or condition-based triggers.

Does MTBM include preventive maintenance?

Yes. That is its defining feature. Counting PMs alongside corrective work gives a complete picture of total maintenance demand on the asset.

Maintenance & Reliability calculator

Mean Time Between Maintenance Calculator

Mean Time Between Maintenance (MTBM) is the average operating time a machine or fleet runs between maintenance actions of any kind, both corrective and preventive. Unlike MTBF, which counts only failures, MTBM captures every intervention a maintainer touches the asset for, making it a truer measure of total maintenance demand. Reliability engineers and asset managers use it to size crews, forecast spares, and compare the upkeep burden of competing equipment. A rising MTBM means the asset is demanding fewer hands-on interventions per operating hour, which usually translates directly into lower maintenance cost and higher availability.

What this calculator does

Measure mean time between maintenance actions by dividing operating time by planned and unplanned maintenance events.
Use it when you want a broader interval than MTBF that includes both preventive and corrective maintenance demand.
It computes average operating hours per maintenance action, then scales that by a normalization factor to match your reporting basis.

Formula used

MTBM = total operating time ÷ total maintenance actions
Normalized MTBM = MTBM × normalization factor

Inputs explained

Total operating time:
Total maintenance actions:
Normalization factor:

How to use the result

Use it to benchmark maintenance demand across assets, justify crew sizing, and track whether reliability programs are reducing intervention frequency.
It lumps all maintenance actions together, so a minor lube top-off counts the same as a major rebuild and can mask where labor truly goes.

Current U.S. benchmarks

U.S. manufacturing runs at 75.6% of capacity (Federal Reserve, May 2026). New factory orders are up 2.3% year over year (Census).

Common questions

How do you calculate mean time between maintenance? Divide total operating time by the total number of maintenance actions. For 7,200 operating hours and 30 actions, MTBM = 7,200 ÷ 30 = 240 hours per action.
What is the difference between MTBM and MTBF? MTBF counts only failures (corrective events), while MTBM counts every maintenance action including preventive and inspection tasks. MTBM is therefore always lower than or equal to MTBF for the same asset.
What is a good MTBM value? There is no universal number; it depends on asset type. The goal is a rising trend. An MTBM of 240 hours means roughly one maintenance touch every 10 days of continuous run time.
What is the normalization factor for? It converts the base hours-per-action into another basis, such as per duty cycle or per shift, or applies a fleet correction. Leaving it at 1 reports raw hours per action.
How can I increase MTBM? Eliminate recurring failure modes through root cause analysis, optimize over-frequent PM intervals, and design out maintenance with better seals, filters, or condition-based triggers.

Last reviewed 2026-05-12.