How do you calculate downstream pack rate?

Divide containers packed downstream by containers produced at the blow molder and multiply by 100. With 39,600 packed out of 42,000 produced, that is 94.29% packed.

What is a good downstream pack rate for blow molding?

Mature PET and HDPE lines often run 97-99% pack-through. The 94.29% in the example is 3.71 points under a 98% target — recoverable, and usually traceable to a single dominant reject like leakers or label misapplication.

What is the difference between pack rate and scrap rate?

Pack rate is the share that survives to packing; scrap rate is the share lost. They sum to 100% of molded output. Here a 94.29% pack rate means a 5.71% downstream loss.

Why is my pack rate below the molder's yield?

The molder can mold a good-looking container that later fails leak test, fails vision inspection, or gets crushed on the conveyor. Those post-mold losses are exactly what this rate captures and a wheel-level yield number hides.

How many containers does the gap represent?

In the example the 3.71-point gap to a 98% target is about 1,560 containers per 42,000 produced. Closing it recovers that many sellable units at the same resin and energy spend.

Pack rate vs first-pass yield — which should I track?

Track both. First-pass yield includes mold-station rejects; downstream pack rate isolates losses after the mold. Watching them separately tells you whether to tune the mold or fix the packing line.

Blow Molding & Hollow Plastic Products calculator

Downstream Pack Rate Calculator

Downstream pack rate is the percentage of containers a blow molder produces that actually make it through leak testing, labeling and case packing as sellable units. It is the survival rate between the molder and the pallet, and packaging supervisors and quality managers watch it because every point lost is a bottle that was made, energized and resin-filled but never shipped. A blow line can look fast at the wheel while the downstream gap quietly eats yield through leakers, ovality rejects, vision-system kickouts and handling damage. Because it compares molded output to packed output, it isolates losses that happen after the mold — exactly the ones a line speed report misses.

What this calculator does

Calculate the percentage of blow molded output that downstream packing, bagging, boxing, palletizing, or sleeving can absorb against a target pack rate.
a blow molding cell needs to check whether downstream packing is matching molded bottle or container output
It computes the percentage of molded containers that reach packing and the gap in points between that rate and your target.

Formula used

Downstream pack-through rate = containers packed downstream ÷ containers produced by blow molder × 100
Pack rate gap to target = target downstream pack-through rate - downstream pack-through rate

Inputs explained

Containers packed downstream:
Containers produced by blow molder:
Target downstream pack-through rate:

How to use the result

Use it at end of shift or run to quantify post-mold yield loss and see how far you are from the pack-through target.
It does not tell you why containers were lost — leak test, vision reject or handling damage all read the same; you need reject-code data to act on the gap.

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 downstream pack rate? Divide containers packed downstream by containers produced at the blow molder and multiply by 100. With 39,600 packed out of 42,000 produced, that is 94.29% packed.
What is a good downstream pack rate for blow molding? Mature PET and HDPE lines often run 97-99% pack-through. The 94.29% in the example is 3.71 points under a 98% target — recoverable, and usually traceable to a single dominant reject like leakers or label misapplication.
What is the difference between pack rate and scrap rate? Pack rate is the share that survives to packing; scrap rate is the share lost. They sum to 100% of molded output. Here a 94.29% pack rate means a 5.71% downstream loss.
Why is my pack rate below the molder's yield? The molder can mold a good-looking container that later fails leak test, fails vision inspection, or gets crushed on the conveyor. Those post-mold losses are exactly what this rate captures and a wheel-level yield number hides.
How many containers does the gap represent? In the example the 3.71-point gap to a 98% target is about 1,560 containers per 42,000 produced. Closing it recovers that many sellable units at the same resin and energy spend.

Last reviewed 2026-05-12.