Is midrange the average thickness?

No. It is the midpoint of the two extremes. Calculate the mean from all readings if that statistic is required.

Does a small range prove the coating passes?

No. All readings can cluster away from the target. Check the specified minimum and maximum thickness requirements separately.

Can this estimate process capability?

No. Capability needs an appropriate sample, distribution and specification limits. This model reports observed extremes only.

Which readings should I combine?

Use the sampling set defined by the inspection plan, with consistent units and measurement method. Do not mix unrelated lots or protocols.

Plating, Anodizing & Surface Treatment calculator

Measured Thickness Variation Calculator

Report the range between the smallest and largest coating thickness readings in one sampling set. Compare it with a stated range allowance and nominal target.

What this calculator does

Compare an observed coating thickness range with an entered range allowance and target.

Formula used

Observed range = maximum reading − minimum reading
Range relative to target = observed range ÷ target × 100
Midrange = (maximum reading + minimum reading) ÷ 2
Largest deviation = larger absolute difference between either extreme and target
Range headroom = allowed range − observed range

Inputs explained

Minimum Measured Thickness: Smallest reading from this defined sampling set.
Maximum Measured Thickness: Largest reading from the same sampling set.
Target Thickness: Entered nominal coating thickness.
Allowed Thickness Range: Entered maximum range for the same sampling method.

How to use the result

Best suited to sample thickness range reviews, target deviation checks.
Does not estimate a population range or process capability. Midrange is not the mean of all readings.

Current U.S. benchmarks

The producer price index for industrial chemicals stands at 336.006 (BLS, Aug 2026), up 13.3% from a year earlier. Quotes priced off last quarter's material cost miss this move.
The U.S. has 14,543 chemical manufacturing establishments employing about 911,245 workers (Census County Business Patterns, 2023).

Common questions

Is midrange the average thickness? No. It is the midpoint of the two extremes. Calculate the mean from all readings if that statistic is required.
Does a small range prove the coating passes? No. All readings can cluster away from the target. Check the specified minimum and maximum thickness requirements separately.
Can this estimate process capability? No. Capability needs an appropriate sample, distribution and specification limits. This model reports observed extremes only.
Which readings should I combine? Use the sampling set defined by the inspection plan, with consistent units and measurement method. Do not mix unrelated lots or protocols.

Last reviewed 2026-10-06.