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How much stock or how many calendar slots to open this year, as a number
Multiply your normal capacity today by your last peak's growth factor, and you'll know how much stock or how many slots to open this season, with extra margin only if you sell products.
By Yodai · Published September 6, 2026 · Updated October 12, 2026
When your busy season gets close, the question that really keeps you up at night shows up: how much do I open this year? If you sell T-shirts, how many do you order? If you teach classes or book appointments, how many slots do you release on the calendar?
Most people guess. "Last year we ran short, so this year I'm ordering more." And they order twenty percent more because it sounds like a reasonable number. It isn't: it doesn't come from any of your own data, it comes from the feeling that "more" beats "the same."
You have a better number waiting in your own history. It's called your growth factor, and it comes straight from last year's numbers.
You already have your growth factor
Your growth factor is the ratio between what you sold at your peak and what you sell in a normal week. If you bring in $800 in a normal week and $2,000 in the strongest week of your busy season, the factor is $2,000 divided by $800: 2.5. Your peak multiplies your normal pace by 2.5.
That 2.5 isn't a one-time fluke from last year. It's how your business grows when its moment comes. Unless something big has changed (you opened a physical store, a strong competitor showed up, you raised your prices a lot), that factor tends to repeat. Peak-season demand isn't random: it's driven by the calendar, and the calendar comes back around.
So the amount you open up this year doesn't come from a gut feeling. It comes from multiplying your normal weekly capacity by that factor.
- 1Write down your normal capacity
How many units you sell, or how many appointments you fill, in a typical week outside your busy season. If you sell 40 units on average, that's your starting point. - 2Find your peak factor
Divide what you sold in your strongest week last year by a normal week. If it was 100 units versus 40 normally, the factor is 2.5. - 3Multiply
Normal capacity times factor: 40 times 2.5 is 100 units, or 100 appointment slots, for peak week. That's your baseline figure, not a padded one. - 4Spread it across weeks
If your busy season lasts three weeks and the peak is the middle one, don't open 100 for all three weeks. Open a bit less for the first and last weeks, say 70% of the peak, and 100% for the middle week.
The margin isn't a guess, it's a fixed rule
The number you calculate is one thing; the safety margin you add on top is another. Here too, there's a way to decide without guessing: it depends on whether running short or having leftovers costs you more.
If you sell a physical product and you end up with extra stock, the downside is money sitting in the warehouse until you clear it out at a discount. If you run short, the downside is a customer who doesn't come back. Losing a customer almost always outweighs a dollar sitting on the shelf, so the margin leans toward not running short: add an extra 10% to your calculation.
If you sell appointments or bookings, there's no warehouse: a slot that goes unused this week can't be sold next week. Here, margin works backward: open exactly the number you calculated, no extra, because a slot nobody books doesn't carry over to next week. It's your time, or your team's time, reserved for nothing.
- Leftover stock sits in the warehouse and has to be cleared out
- Running short sends the customer somewhere else, and they don't come back
- Recommended margin: +10% on top of your calculation
- An empty slot can't be recovered or sold later
- Opening up more just spreads your schedule thin across slow slots
- Recommended margin: 0%, the calculated number as is
Which one to pick: If what you sell is an item that sits on a shelf, add margin, because running short costs more than having extra. If what you sell is your time, don't add anything: the exact number is already your real limit.
With this number, you can call your supplier or open the calendar with an actual date and figure, not with the feeling of "let's order a little more just in case." And if you're wondering exactly where that week comes from, the one when you need to start moving, it comes from counting backward from the peak.
What changes with this calculation is that you're no longer reacting on the fly when you see stock running out or your calendar filling up. You decide ahead of time, with the number right there on the table.
- You have your growth factor: your peak divided by your normal week
- You know how to multiply your capacity today (not last year's) by that factor
- You know whether to add a margin (product) or leave the number as is (schedule)
- You have the exact number of units or slots to open this season, with a date attached
- The next lesson figures out from what date you can raise your price without losing those sales