MedTech Calculations

How to Calculate Core Metrics in Medical Device Manufacturing

Work through the five formulas that matter most on a medical device line, from cleanroom cost per part to sterilization cycle time, with real inputs and units.

Fully loaded unit cost in a regulated device line is the sum of direct material, direct labor, allocated cleanroom time, sterilization share, and QA sampling, divided by good units. Start with a Class II injection-molded housing: 4.2 g of medical PC at 6.50 dollars per kg gives 0.027 dollars of resin. Add a 0.11 dollar direct labor touch at 42 seconds and a 21 dollar per hour rate. Cleanroom and sterilization allocations come next. The Medical Device Unit Cost calculator chains these lines so you do not lose a component; a missed 0.008 dollar bioburden line across 2 million units is 16,000 dollars a year.

Cleanroom cost per part is the driver most estimators underweight. Take total cleanroom operating cost per hour, divide by parts produced per hour, then divide by yield. An ISO 7 (Class 10,000) suite running HVAC, gowning consumables, and 6 operators might cost 380 dollars per hour all in. At 900 conforming parts per hour, that is 0.422 dollars per part before yield. At 96 percent first-pass yield, divide by 0.96 to get 0.440 dollars. Cleanroom Cost Per Part and Cleanroom Labor Cost split the fixed HVAC burden from the variable operator burden so you can see which one moves.

Gowning time is real capacity you pay for but never ship. If a full ISO 5 gown-up runs 6 minutes and de-gown 2 minutes, each entry burns 8 minutes. With 6 operators entering twice per shift, that is 96 minutes of paid labor per shift producing nothing. At 21 dollars per hour that is 33.60 dollars per shift, or roughly 21,000 dollars a year across two shifts. Cleanroom Gowning Time converts entries per shift and crew size into lost hours so you can fold that overhead into the per-part rate rather than pretending gowning is free.

Cleanroom utilization tells you whether the suite is earning its fixed cost. Utilization equals productive machine or line hours divided by scheduled cleanroom hours. A suite scheduled 6,000 hours per year that runs value-added work 4,200 hours is at 70 percent. Because HVAC and monitoring run whether or not parts move, every idle hour still spends the same 380 dollars. Cleanroom Utilization exposes this: lifting utilization from 70 to 82 percent on that suite spreads the same 2.28 million dollar annual fixed cost across 720 more productive hours, cutting the fixed portion of cost per part by roughly 15 percent.

Sterilization cost per unit depends on cycle economics, not per-piece handling. Compute cost per validated cycle, then divide by units per load. An EO cycle costing 1,450 dollars all in (gas, aeration energy, dosimetry, labor) loaded with 3,200 units is 0.453 dollars per unit. Gamma at a contract irradiator quoted per pallet behaves differently: a 2,800 dollar pallet dose holding 9,600 units is 0.292 dollars. Sterilization Cost Per Unit and Sterilization Batch Capacity let you test load configurations, because filling that EO chamber to 3,800 units drops the unit cost to 0.382 dollars with no added cycle cost.

Sterilization cycle time governs throughput and WIP. An EO cycle is preconditioning plus dwell plus aeration: 12 hours precondition, 6 hours dwell, and often 168 hours aeration for the residuals to clear. That 186-hour clock means a batch tied up for nearly 8 days, so you must carry roughly 8 days of finished-but-unreleased inventory. Sterilization Cycle Time sums each phase so planners size the quarantine floor correctly. Gamma by contrast is measured in hours of exposure, which is why aeration-free methods reduce WIP even when the per-unit dose cost looks similar.

Validation batch cost is a per-launch amortized number, not a running cost. IQ, OQ, and PQ commonly require 3 consecutive PQ batches plus protocol authoring and review. If each validation batch consumes 8,000 dollars in material and time and you run 3, plus 24,000 dollars of protocol and engineering hours, total validation is 48,000 dollars. Amortize across expected lifetime volume: over 1.2 million units that is 0.040 dollars per unit; over 200,000 units it is 0.240 dollars. The Validation Batch Cost calculator makes this allocation explicit so short-run programs do not get quoted as if validation were free.

Chaining these together gives a defensible unit cost. For the molded housing at 900 parts per hour: 0.027 material, 0.110 direct labor, 0.440 cleanroom, 0.453 EO sterilization, plus 0.040 amortized validation and roughly 0.008 bioburden sampling equals about 1.078 dollars per good unit before overhead and margin. Change one input and you see the sensitivity: raising first-pass yield from 96 to 99 percent trims the cleanroom line by about 0.013 dollars, and filling the sterilizer trims another 0.071 dollars. That is why each calculator isolates one variable rather than burying it in a single blended rate.

Published 2026-07-01.