How do you calculate good shippable ramp capacity?

Multiply stacks per shift by planned shifts for gross capacity, then multiply by line uptime and first-pass shipping yield. With 6 stacks/shift over 60 shifts at 82% uptime and 94% yield, you get about 277 good shippable stacks.

What is the difference between gross and shippable capacity?

Gross capacity (here 360 stacks) assumes perfect uptime and zero defects. Shippable capacity subtracts uptime loss (about 65 stacks) and yield loss (about 18 stacks), leaving roughly 277 stacks you can actually deliver.

What is a good first-pass shipping yield for stacks?

Mature stack lines target high-90s first-pass yield, but early-ramp lines often sit in the low- to mid-90s as leak and crossover failures get designed out. The default 94% reflects a line still climbing the yield curve.

How much is one point of uptime worth in stacks?

At the default inputs, gross capacity is 360 stacks and yield is 94%, so each point of uptime is roughly 360 times 0.01 times 0.94, about 3.4 shippable stacks. That makes uptime improvements directly bankable.

Why multiply uptime and yield instead of adding losses?

They compound: yield only applies to stacks the line actually produced during uptime. Multiplying captures that a stack lost to downtime is never at risk of a yield failure, avoiding double-counting.

Should I plan the ramp to gross or shippable capacity?

Always commit to shippable. Promising gross (360) when you can ship 277 builds a 30% shortfall into the plan before the first shift runs.

Hydrogen Electrolyzer & Fuel Cell Manufacturing calculator

Production Ramp Capacity Calculator

Production Ramp Capacity converts a stack line's per-shift target into the number of good, shippable stacks you can realistically deliver in a period, after line uptime and end-of-line first-pass yield take their bite. Operations and ramp managers use it to set credible commitments during the steep part of an electrolyzer or fuel cell scale-up, when both equipment reliability and stack yield are still maturing. Gross capacity always flatters; the gap between gross and shippable is where ramp plans miss their numbers. This calculator makes uptime loss and yield loss explicit so you can promise — and staff — to a number you can actually ship.

What this calculator does

Estimate good shippable stacks per period across the assembly line during ramp-up from stacks per shift, planned shifts in the period, line uptime, and end-of-line first-pass shipping yield.
Use it when a production manager or operations lead is sizing the ramp curve for a new PEM, alkaline, SOEC, or SOFC stack program and needs to show finance and the customer how many shippable stacks the line can deliver each month during ramp.
It computes good shippable stacks by multiplying gross capacity (per-shift target times planned shifts) by line uptime and first-pass shipping yield.

Formula used

Gross ramp capacity = stacks per shift × planned shifts
Good shippable ramp capacity = gross capacity × line uptime × first-pass shipping yield

Inputs explained

Stacks per shift target:
Planned shifts in the period:
Line uptime:
End-of-line first-pass shipping yield:

How to use the result

Use it to set deliverable ramp commitments, size buffers, and quantify how much uptime or yield improvement is worth in extra shippable stacks.
It uses single period-average uptime and yield figures; early-ramp lines improve week over week, so a single average can over- or under-state any given week's true capacity.

Current U.S. benchmarks

Global copper trades at $13,484 per tonne (IMF via FRED, May 2026), up 41.5% in a year, and U.S. industrial electricity averages 8.66 cents per kWh. Both feed electrified-hardware unit economics.

Common questions

How do you calculate good shippable ramp capacity? Multiply stacks per shift by planned shifts for gross capacity, then multiply by line uptime and first-pass shipping yield. With 6 stacks/shift over 60 shifts at 82% uptime and 94% yield, you get about 277 good shippable stacks.
What is the difference between gross and shippable capacity? Gross capacity (here 360 stacks) assumes perfect uptime and zero defects. Shippable capacity subtracts uptime loss (about 65 stacks) and yield loss (about 18 stacks), leaving roughly 277 stacks you can actually deliver.
What is a good first-pass shipping yield for stacks? Mature stack lines target high-90s first-pass yield, but early-ramp lines often sit in the low- to mid-90s as leak and crossover failures get designed out. The default 94% reflects a line still climbing the yield curve.
How much is one point of uptime worth in stacks? At the default inputs, gross capacity is 360 stacks and yield is 94%, so each point of uptime is roughly 360 times 0.01 times 0.94, about 3.4 shippable stacks. That makes uptime improvements directly bankable.
Why multiply uptime and yield instead of adding losses? They compound: yield only applies to stacks the line actually produced during uptime. Multiplying captures that a stack lost to downtime is never at risk of a yield failure, avoiding double-counting.

Last reviewed 2026-05-12.