How do you calculate leak-test capacity?

Multiply containers tested per cycle by available cycles for gross slots, then multiply by uptime and first-pass yield. Here 4 per cycle times 1,800 cycles is 7,200 gross slots; at 94% uptime and 98% yield that nets 6,633 accepted containers.

What is the difference between gross and accepted leak-test capacity?

Gross capacity is the raw slot count, 7,200 in the example, assuming the tester never stops and never rejects. Accepted capacity, 6,633, is what actually passes after 432 units lost to downtime and about 135 lost to rejects and retest.

What is a good first-pass leak-test yield?

For mature blow-molded bottle lines, 97-99% first-pass yield is typical. The example's 98% is healthy; a yield falling below 95% usually points to pinch-off leaks, weld-line defects, or a drifting test pressure rather than random variation.

How does leak tester uptime affect capacity?

It scales gross capacity directly. At 94% uptime the station loses 432 of 7,200 slots before any reject. Pushing uptime to 98% would recover roughly 288 of those, a meaningful gain when the tester is the line bottleneck.

Why does my leak tester bottleneck the line?

Usually because accepted capacity falls below molding output. If the molders feed more bottles per shift than the 6,633 the tester can accept, bottles back up. Raising units per cycle, cycles, uptime, or yield each lifts the ceiling.

Should rejected bottles be retested or scrapped?

It depends on the failure mode. Marginal leakers can be retested and many pass, recovering capacity, but consistent gross leakers from tooling defects should be scrapped. This calculator books reject and retest as a single loss of about 135 units.

Blow Molding & Hollow Plastic Products calculator

Leak Test Capacity Calculator

Leak Test Capacity tells you how many blow-molded containers your leak detection station can actually pass per shift after downtime and reject losses, which sets the true throughput ceiling for any bottle that must hold pressure or vacuum. Production planners use it to confirm the leak tester can keep up with the molding machines feeding it, since a tester that bottlenecks at end of line strands good bottles and starves downstream filling. Quality engineers use it to separate gross capacity from accepted capacity, because uptime and first-pass yield each carve real units off the theoretical number. This calculator chains those four factors into a single accepted-container figure and breaks out exactly where the losses go.

What this calculator does

Estimate accepted leak-tested bottle, container, drum, or tank output from test heads per cycle, available cycles, tester uptime, and first-pass leak yield.
a blow molding cell needs to confirm leak-test throughput before committing production or shipping volume
It multiplies containers per cycle by available cycles to get gross slots, then derates by leak tester uptime and first-pass yield to give accepted container capacity, and itemizes the downtime and reject losses.

Formula used

Gross leak-test slots = containers tested per cycle × available leak-test cycles
Accepted leak-test capacity = gross leak-test slots × leak tester uptime × first-pass leak-test yield

Inputs explained

Containers tested per leak-test cycle:
Available leak-test cycles:
Leak tester uptime:
First-pass leak-test yield:

How to use the result

Use it when sizing or balancing an end-of-line leak test against molding output, or when validating whether a station can absorb a planned production increase.
It assumes uptime and yield are independent and constant; in reality a struggling tester often loses uptime and yield together, and retest loops can recover some rejected units it does not credit.

Current U.S. benchmarks

The producer price index for plastic resins and materials stands at 319.371 (BLS, May 2026), up 19.5% from a year earlier. Quotes priced off last quarter's material cost miss this move.
The U.S. has 9,635 plastics product manufacturing establishments employing about 677,302 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate leak-test capacity? Multiply containers tested per cycle by available cycles for gross slots, then multiply by uptime and first-pass yield. Here 4 per cycle times 1,800 cycles is 7,200 gross slots; at 94% uptime and 98% yield that nets 6,633 accepted containers.
What is the difference between gross and accepted leak-test capacity? Gross capacity is the raw slot count, 7,200 in the example, assuming the tester never stops and never rejects. Accepted capacity, 6,633, is what actually passes after 432 units lost to downtime and about 135 lost to rejects and retest.
What is a good first-pass leak-test yield? For mature blow-molded bottle lines, 97-99% first-pass yield is typical. The example's 98% is healthy; a yield falling below 95% usually points to pinch-off leaks, weld-line defects, or a drifting test pressure rather than random variation.
How does leak tester uptime affect capacity? It scales gross capacity directly. At 94% uptime the station loses 432 of 7,200 slots before any reject. Pushing uptime to 98% would recover roughly 288 of those, a meaningful gain when the tester is the line bottleneck.
Why does my leak tester bottleneck the line? Usually because accepted capacity falls below molding output. If the molders feed more bottles per shift than the 6,633 the tester can accept, bottles back up. Raising units per cycle, cycles, uptime, or yield each lifts the ceiling.

Last reviewed 2026-05-12.