How do you calculate the capacity gap on an assembly line?

Multiply units per cycle by available cycles to get gross capacity, then multiply that by uptime and first-pass yield to get good capacity. With 4 units/cycle over 480 cycles at 90% uptime and 97% yield, gross is 1,920 units and good capacity is 1,676 units, so the gap is about 244 units per shift.

What is the difference between gross and good build capacity?

Gross build capacity is the raw theoretical maximum (4 x 480 = 1,920 units) assuming zero stoppages and zero defects. Good build capacity (1,676 units) is what survives after downtime and first-pass yield losses, and it is the number you should commit to dealers.

What is a good uptime for an outdoor power equipment line?

Well-run OPE assembly lines typically run 85-92% uptime in peak season; the 90% default sits in that band. Every point of uptime in this example is worth roughly 19 good units per shift, so chasing the last few points pays off when you are order-constrained.

How much output am I losing to assembly defects?

At 97% first-pass yield the calculator shows about 52 units of yield loss per shift. That is the count of units pulled for rework or scrap before downtime is even considered, and it is the lever a quality project would target.

Why is downtime loss larger than yield loss here?

Downtime is applied to the full gross number (1,920 units at 10% lost = 192 units) while yield acts on the already-reduced figure (52 units). On most OPE lines uptime is the bigger swing factor, which is why availability projects usually beat quality projects on raw unit recovery.

Can I use this for a whole week instead of a shift?

Yes. Set available cycles to the cycles in your planning window. Keep units per cycle, uptime, and yield as the line's true sustained rates, and the good-capacity output scales directly to that horizon.

Outdoor Power Equipment calculator

Capacity Gap Calculator

Capacity Gap tells an outdoor power equipment plant how many sellable mowers, trimmers, or blowers a line can actually finish once downtime and assembly defects are stripped out of the theoretical number. Production planners and value-stream managers use it to separate the headline output the line could hit from the good-unit output it really delivers. On a seasonal OPE line that runs flat out from late winter through summer, the gap between gross and good capacity is the difference between filling dealer orders and stocking out. It turns vague talk of 'we lost some time' into a hard unit count you can defend in an S&OP meeting.

What this calculator does

Estimate good buildable units per shift from cycle output, available cycles, line uptime, and first-pass yield to test capacity against demand.
a production planner needs realistic good output per shift to compare against demand and spot a capacity gap
It computes good build capacity (gross cycle output adjusted for line uptime and assembly first-pass yield) and breaks out the units lost to downtime and to yield separately.

Formula used

Gross build capacity = units built per cycle × available build cycles
Good build capacity = gross build capacity × build line uptime × assembly first-pass yield

Inputs explained

Units built per cycle:
Available build cycles:
Build line uptime:
Assembly first-pass yield:

How to use the result

Use it when sizing a shift's committed output, validating a takt plan against firm dealer orders, or deciding whether overtime or a yield project closes a shortfall.
It assumes uptime and first-pass yield are independent multipliers and stable across the run; a line with batch-correlated defects or a single chronic bottleneck station can deviate from this simple product.

Current U.S. benchmarks

U.S. housing starts run at 1,177k per year (Census, May 2026), down 8.7% from a year earlier, the demand driver for building products.
Steel mill PPI stands at 348.53 (BLS, May 2026), up 6.7% from a year earlier. New factory orders are up 2.3% year over year (Census).

Common questions

How do you calculate the capacity gap on an assembly line? Multiply units per cycle by available cycles to get gross capacity, then multiply that by uptime and first-pass yield to get good capacity. With 4 units/cycle over 480 cycles at 90% uptime and 97% yield, gross is 1,920 units and good capacity is 1,676 units, so the gap is about 244 units per shift.
What is the difference between gross and good build capacity? Gross build capacity is the raw theoretical maximum (4 x 480 = 1,920 units) assuming zero stoppages and zero defects. Good build capacity (1,676 units) is what survives after downtime and first-pass yield losses, and it is the number you should commit to dealers.
What is a good uptime for an outdoor power equipment line? Well-run OPE assembly lines typically run 85-92% uptime in peak season; the 90% default sits in that band. Every point of uptime in this example is worth roughly 19 good units per shift, so chasing the last few points pays off when you are order-constrained.
How much output am I losing to assembly defects? At 97% first-pass yield the calculator shows about 52 units of yield loss per shift. That is the count of units pulled for rework or scrap before downtime is even considered, and it is the lever a quality project would target.
Why is downtime loss larger than yield loss here? Downtime is applied to the full gross number (1,920 units at 10% lost = 192 units) while yield acts on the already-reduced figure (52 units). On most OPE lines uptime is the bigger swing factor, which is why availability projects usually beat quality projects on raw unit recovery.

Last reviewed 2026-05-12.