Can I shrink the sample size to save inspection time?

Only through your sampling plan. Its sample size and accept number fix the operating characteristic curve: the chance of accepting a lot at each defect level. A smaller sample changes that protection.

What goes into setup and records per lot?

Everything done once per lot, not per unit: pulling the instruction, verifying gauges, setting up fixtures, and the inspection and batch record entries. It does not shrink with the sample.

How many inspectors does a shift need for these lots?

Divide the minutes your lots need by one inspector's working minutes per shift, then round up. If one inspector works 450 minutes, 4 lots at 90 minutes need 360, so one inspector covers the shift at 80% load.

Does a vision system or CMM change the calculation?

Only the inputs. Automated inspection cuts time per point, but program loading and system verification belong in setup per lot; update both and compare the load.

MedTech Manufacturing calculator

Medical Device Inspection Time Calculator

Find how long one lot takes to inspect and whether the shift's inspectors can clear the lots scheduled. You need the sample size, points per unit, time per point, setup and records time, lots per shift and inspector minutes.

What this calculator does

Minutes to inspect one lot from its sample, points and time per point, and whether your inspectors can clear a shift's lots.

Formula used

Checks per lot = sample size × inspection points per unit
Measurement time (min) = checks per lot × time per point (s) ÷ 60
Inspection time per lot = measurement time + setup and records; setup and records share = setup and records ÷ inspection time per lot
Inspection load = lots per shift × inspection time per lot ÷ inspector minutes per shift
Headroom = inspector minutes − lots × inspection time per lot; lot capacity = inspector minutes ÷ inspection time per lot

Inputs explained

Sample Size: Units your sampling plan pulls per lot; every unit for 100% inspection.
Inspection Points per Unit: Characteristics checked on each sampled unit, from the inspection instruction.
Time per Point: Handle, measure and record one point, from a time study.
Setup and Records per Lot: Gauge verification, fixture setup and inspection record entry, timed per lot.
Lots to Inspect per Shift: Lots the schedule sends to inspection each shift, averaged over a week.
Inspector Minutes per Shift: Inspectors on shift × working minutes each, after breaks and meetings.

How to use the result

Best suited to staffing an inspection cell for a new product, pricing the time a vision system saves.
Rejected lots sent to 100% inspection take longer; rerun with the full lot as the sample. Destructive tests, outside lab results and first article layouts are not counted.

Current U.S. benchmarks

U.S. manufacturing runs at 75.7% of capacity with new factory orders at $663B per month (Federal Reserve and Census, Aug 2026).
The U.S. has 8,825 medical equipment and supplies establishments employing about 308,388 workers (Census County Business Patterns, 2023).

Common questions

Can I shrink the sample size to save inspection time? Only through your sampling plan. Its sample size and accept number fix the operating characteristic curve: the chance of accepting a lot at each defect level. A smaller sample changes that protection.
What goes into setup and records per lot? Everything done once per lot, not per unit: pulling the instruction, verifying gauges, setting up fixtures, and the inspection and batch record entries. It does not shrink with the sample.
How many inspectors does a shift need for these lots? Divide the minutes your lots need by one inspector's working minutes per shift, then round up. If one inspector works 450 minutes, 4 lots at 90 minutes need 360, so one inspector covers the shift at 80% load.
Does a vision system or CMM change the calculation? Only the inputs. Automated inspection cuts time per point, but program loading and system verification belong in setup per lot; update both and compare the load.

Last reviewed 2026-10-01.