Glossary

What is wrench time?

Quick answer

Wrench time is the proportion of a tradesperson's paid shift spent actually doing hands-on maintenance work, as opposed to waiting, travelling, finding parts, getting permits, or attending meetings. Many plants sit around 25 to 35 percent wrench time; well-planned operations reach 50 percent or more.

FormulaWrench time % = (hands-on work hours / total paid hours) x 100

Benchmark

Benchmark
Good50 percent or above is strong. Best practice planning and scheduling can push it higher.
Warning signBelow 30 percent means most of the maintenance wage bill is being spent on waiting, not working.

Why it matters

Wrench time is the clearest measure of labour leak. Lifting it from, say, 30 to 45 percent is the equivalent of adding half your crew again without hiring anyone. The causes, waiting for parts, permits, access, and decisions, are almost all fixable with planning and scheduling discipline.

How to improve it

Plan and kit jobs before they reach the schedule, hold a ready backlog of fully prepared work, coordinate access and permits ahead of time, and measure the top causes of waiting so they can be removed.

Frequently asked questions

What is a good wrench time percentage?
Around 50 percent is considered strong. Many plants operate at 25 to 35 percent, so there is usually a large, recoverable gap created by waiting rather than by the crew working slowly.
How do you measure wrench time?
Through structured work sampling or activity logging over a representative period, categorising each observation as hands-on work or one of the waiting and support categories.

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