# Maintenance Crew Size Calculator > Source: https://netray.co/tools/maintenance-crew-size-calculator > Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems. > Section: Free Tools ## Short answer Work out how many maintenance technicians you need from monthly workload, wrench time, absence and a target to clear the backlog. ## Category maintenance ## Audience - Maintenance manager - Plant manager - Maintenance planner ## Tool **Kind:** calculator **Inputs:** #### Preventive maintenance hours per month **Key:** pm_hours **Type:** number **Default:** 420 **Min:** 0 **Step:** 10 **Unit:** h #### Corrective and breakdown hours per month **Key:** cm_hours **Type:** number **Default:** 520 **Min:** 0 **Step:** 10 **Unit:** h #### Project and improvement hours per month **Key:** proj_hours **Type:** number **Default:** 120 **Min:** 0 **Step:** 10 **Unit:** h #### Current backlog **Key:** backlog **Type:** number **Default:** 1800 **Min:** 0 **Step:** 50 **Unit:** h **Help:** Estimated hours of approved, ready work. #### Weeks to clear the backlog **Key:** target_weeks **Type:** slider **Default:** 26 **Min:** 4 **Max:** 104 **Step:** 1 **Unit:** weeks #### Paid hours per technician per month **Key:** hours_per_tech **Type:** number **Default:** 173 **Min:** 100 **Step:** 1 **Unit:** h #### Leave, training and absence **Key:** absence **Type:** slider **Default:** 15 **Min:** 0 **Max:** 40 **Step:** 1 **Unit:** % #### Wrench time **Key:** wrench **Type:** slider **Default:** 40 **Min:** 20 **Max:** 70 **Step:** 1 **Unit:** % **Help:** Share of the working day on hands-on work. Typical plants measure 25 to 50%. **Outputs:** #### Recurring workload per month **Key:** demand **Expr:** pm_hours + cm_hours + proj_hours **Format:** number #### Backlog burn-down per month **Key:** backlog_burn **Expr:** backlog / (target_weeks / 4.33) **Format:** number **Description:** Hours per month needed to clear the backlog in the target time. #### Total work hours per month **Key:** total_demand **Expr:** demand + backlog_burn **Format:** number #### Productive hours per technician **Key:** productive **Expr:** hours_per_tech * (1 - absence / 100) * wrench / 100 **Format:** decimal **Description:** Paid hours less absence, times wrench time. #### Technicians for steady-state work **Key:** techs_steady **Expr:** demand / productive **Format:** decimal #### Technicians including backlog burn **Key:** techs_required **Expr:** total_demand / productive **Format:** decimal **Primary:** true #### Headcount to plan (rounded up) **Key:** techs_round **Expr:** ceil(techs_required) **Format:** integer **Primary:** true **Chart:** #### Technicians required vs wrench time **Type:** line **X:** wrench **From:** 25 **To:** 65 **Steps:** 20 **Series:** - techs_required **Disclaimer:** A planning estimate. Real staffing also depends on skill mix, shift coverage, safety minimums, overtime policy and contractor use. ## Content **Intro:** Staffing arguments are easier when the arithmetic is on the table. This calculator turns your monthly maintenance workload and backlog into a headcount, after allowing for absence and the share of the day technicians actually spend on hands-on work. **Sections:** #### How to use the calculator **Body:** Enter monthly hours for preventive, corrective and project work, taken from confirmed hours in your CMMS or ERP rather than estimates. Add the backlog in hours and the weeks you want to clear it. Set paid hours, absence and wrench time to your actual values. The result shows technicians required for steady-state work and with backlog burn-down, and a rounded headcount to plan. #### Why wrench time matters most **Body:** Wrench time is the share of a technician's day spent actually working on the job, as opposed to waiting for permits, parts, instructions or transport. Studies in many plants have found it commonly between about 25 and 50 percent. Raising it through better planning and kitting can free more capacity than hiring: with the defaults, moving wrench time from 40 to 50 percent cuts required technicians by about a fifth. Use the chart to see the effect. **Bullets:** - Measure wrench time by sampling, not by asking - Kit parts and prepare permits before the job starts - Count only approved, ready work in the backlog - Use confirmed hours, not planned hours, as workload #### Interpreting the result **Body:** If steady-state staffing is below your current crew, but backlog burn pushes it above, the question is whether the backlog is real work or stale requests. Review it first. If demand exceeds crew even in steady state, you have a structural gap that overtime or contractors can only temporarily cover. The calculator does not set shift coverage or skills; check those with a skills matrix. #### Common mistakes **Body:** Teams often treat paid hours as productive hours, leave out absence and training, or include work that should not exist, such as repeated breakdowns caused by missed PM. Reduce reactive hours through reliability work before adding headcount. **Cta:** If your workload hours are hard to extract from your ERP or CMMS, we can help build a reliable report of confirmed hours by work type. **Faq:** #### What is a realistic wrench time? **Answer:** Many plants measure between about 25 and 50 percent when sampled honestly, with well-planned operations reaching the upper end or beyond. Measure yours by observation over a few weeks before relying on any benchmark figure. #### Should I include overtime in the calculation? **Answer:** Treat overtime as a buffer, not baseline capacity. Plan headcount from normal paid hours, then use overtime and contractors for peaks and shutdown work. Relying on regular overtime tends to raise absence, error rates and turnover. #### How is backlog burn calculated? **Answer:** Backlog hours are divided by the number of months in your target period, using 4.33 weeks per month. This gives extra hours needed each month on top of normal work. If the backlog is unrealistic, shorten the list before staffing for it. #### Does this give shift coverage? **Answer:** No. It sums total capacity. Shift patterns, minimum cover for emergencies and skill coverage on each shift need separate checks. Add the result to a skills matrix and shift roster before deciding on hiring. ## Search terms maintenance crew size calculator, how many maintenance technicians do I need, maintenance staffing calculator, maintenance manpower planning, wrench time staffing calculation, maintenance headcount calculator, maintenance workload to fte --- Talk to an engineer: https://netray.co/contact?intent=erp_ai | Machine catalog: https://netray.co/agent/catalog.json