What do the next four quarters of demand actually look like?
Most demand plans start with the same sentence: take last year and add a few percent. That gets the year roughly right and every single quarter badly wrong, because the business does not sell evenly across the year. This template reads five years of quarterly history and hands back four quarters that keep the rhythm.
Operations Intermediate Forecasting free
After you install, this is the model to open.
Seasonal Demand Forecast
- 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
One click returns the four quarters. The interesting part is not the forecast on its own, it is how far the flat plan sits from it.
- Q1 forecast
- 47,970 units
- Q4 forecast
- 69,510 units
- Q4 gap under a flat plan
- 11,860 units short (17%)
- Annual totals differ by
- 0.6% yet Q1 is off by 20%
The forecast comes back at 47,970 units in Q1 and 69,510 in Q4, about 229,000 for the year, and it tracks the five years of history to an average error of 1.1%. Growing last year's 216,750 by the 6.4% you just grew and splitting it evenly gives 57,660 a quarter and 230,620 for the year, so the two plans agree on the year to within 0.6%. Every quarter is still wrong: the flat plan buys roughly 9,680 units too many in Q1 and comes up 11,860 short in Q4, the quarter you cannot afford to miss. That is cash tied up in January stock and empty shelves in December, from a plan whose annual number looked fine.
The model
The sheet holds one column: 20 quarters of units shipped for a regional specialty retailer, oldest first. Nothing else to fill in.
| History supplied | 20 quarters (5 full years) of units shipped |
| Most recent year | 44,680 / 51,210 / 54,240 / 66,620 units (Q1 to Q4) |
| Underlying growth | about 775 units per quarter once season is removed |
| Seasonal shape | Q1 0.83x, Q2 0.94x, Q3 1.00x, Q4 1.23x of the year average |
| Season length | 4 (quarterly data) |
| Forecast horizon | 4 quarters |
| What you compare against | last year plus 6.4%, split evenly at 57,650 a quarter |
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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