If we build one 50% bigger, what will it actually cost?
Doubling capacity almost never doubles cost, yet most capex estimates still multiply by size and add a contingency. This template fits three cost curves to the builds you have already paid for, keeps the one with the lowest average error, and reads the price of the size you are considering off that curve. At the defaults the honest answer is $12.26M for 240,000 cases a week, $665K under the straight-line guess.
Words on this sheet
- Coefficient: How much the outcome moves for each one-unit rise in this input, holding the other inputs still.
Operations Advanced Data Table free
After you install, this is the model to open.
What Does Twice the Capacity Cost?
- In your spreadsheet, click the Sortia icon in the strip of icons down the right-hand edge. No strip? Click the arrow at the bottom-right to open it. You can also use Extensions, then Sortia, then Open Sortia.
- Click Start from a template and put that name in the search box.
- Pick the card with that name and click Load this template. It arrives on a new tab with real numbers already in it.
The answer
Fitted on the six builds, then swept across the candidate sizes.
- Forecast build cost at 240,000 cases/week
- $12.26 million
- Under the straight-line estimate by
- $665 thousand (5.1%)
- Fitted scale exponent (1.00 would be linear)
- 0.82 2x capacity, +77% cost
- Average error of the winning curve
- 2.1% vs 4.7% line, 16.5% exponential
The power curve tracks your six past builds to an average error of 2.1%, against 4.7% for a straight line and 16.5% for an exponential, so it is the only one of the three worth budgeting on. Its exponent of 0.82 says doubling capacity costs about 77% more, not 100% more. At 240,000 cases a week that puts the build at $12.26M, $665K under the straight-line rule of thumb, and $51.08 per case of weekly capacity against $78.00 on your smallest facility.
The model
Six past builds with their weekly capacity and actual cost in today's dollars, plus the capacity you are sizing now.
| Past builds on record | 6 facilities, 20,000 to 160,000 cases/week |
| Actual build costs | $1.56M to $8.90M |
| Curves fitted | Straight line, power (log-log), exponential |
| Fit chosen by | Lowest average percentage error (MAPE) |
| Planned new capacity | 240,000 cases/week, 50% above the largest built |
| What-if sweep | 180,000 to 300,000 cases/week in 20,000 steps |
Once it is in your sheet
- The model arrives with real numbers in it and runs as it stands, so you can press the button first and understand it second.
- Change the numbers to yours. The sheet marks which cells are inputs and which hold formulas, and most labels carry a note explaining the row.
- Press the run button at the bottom of the panel. It is labeled for the tool you are in, and the result lands on its own tab, with a written reading of it beside the figures.
Never used Google Sheets? Start here goes the whole way, in seven steps, and assumes nothing.
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