To decide how much to make, log every day what you prepped, what you sold, what was left, the weather and the day of the week. Group similar days and look at what you sold on each. Then compare two of your own numbers: the profit you miss on each item you run out of, and the money you throw away on each item left over. If running out costs you more than leftovers, prep somewhat above your average; if not, stay near it or below.
What to write down
A notebook is enough. One line a day:
- Date and day of the week
- Weather: sunny, cloudy, drizzle, cold, heavy rain
- Anything special: payday, a match, an event nearby, school holidays
- How much you prepped
- How much you sold
- How much was left and what you did with it
- If you sold out, at what time
The sell-out time matters. If you made 125 and were out by 1:30, demand that day was 125 or more. You do not know how much more, so treat that day as a minimum.
Two or three weeks of notes already tell you something. The guide to the numbers to check every week shows how to turn that notebook into a ten-minute review.
Group the days that are alike
Do not average all your days together. A sunny Monday and a rainy Saturday have little in common. Split by whatever moves sales at your pitch. For a hot drinks cart, cold mornings matter; for an ice cream stand, sunshine. For a stall outside offices, the weekday matters more than the weather.
Your groups come from your own log, not from what another trader does. If after a month Tuesdays and Wednesdays sell the same, merge them.
What running out costs and what leftovers cost
This is the heart of the decision.
- If you run out: you miss the profit on what you did not sell. The customer who found nothing did not pay you, but you also did not spend on what you did not make.
- If there are leftovers: you lose what you spent preparing food that does not sell and will not keep. If a plate or napkin was not used, it is not part of the loss; if the batter goes in the bin, it is.
Be precise about what is lost. Batter, cut fruit and whipped cream get thrown away. Plates, napkins and jars of spread go back in the box. The guide to measuring and costing food waste shows how to put a price on what you throw out.
Worked example: crepes at a Saturday market
You sell crepes at a weekend market for $8.00 each. Your numbers per crepe:
- Prepped before the market (batter, sliced fruit, whipped cream, grated cheese, sliced ham): $1.80. Whatever is left at close gets thrown away.
- Used only when you sell (plate, napkin, spread from the jar): $0.70.
- Each crepe sold: 8.00 − 1.80 − 0.70 = $5.50 profit.
- Each crepe prepped and not sold: you lose $1.80.
Running out costs you $5.50 a crepe; leftovers cost $1.80. Running out hurts about three times as much.
Your log for the last six dry Saturdays shows sales of 88, 95, 102, 110, 116 and 125 crepes. On the 125 day you sold out at 1:30, so demand was at least 125. The average is (88 + 95 + 102 + 110 + 116 + 125) ÷ 6 = 636 ÷ 6 = 106 crepes.
How much to prep? Test four quantities against those six Saturdays. Each day's profit is: crepes sold × $7.30 − crepes prepped × $1.80 (the $7.30 is the price minus the plate and spread, because the prepped cost is already in the $1.80).
| Prep for | Sold over 6 days | Thrown away | Sold × 7.30 | Prepped × 1.80 | Profit over 6 days | Per day |
|---|---|---|---|---|---|---|
| 100 | 583 | 17 | $4,255.90 | $1,080.00 | $3,175.90 | $529.32 |
| 110 | 615 | 45 | $4,489.50 | $1,188.00 | $3,301.50 | $550.25 |
| 120 | 631 | 89 | $4,606.30 | $1,296.00 | $3,310.30 | $551.72 |
| 130 | 636 | 144 | $4,642.80 | $1,404.00 | $3,238.80 | $539.80 |
How the sold column works: prepping for 100, the 102, 110, 116 and 125 days only sell 100, so 88 + 95 + 100 + 100 + 100 + 100 = 583. For 110: 88 + 95 + 102 + 110 + 110 + 110 = 615. For 120: 88 + 95 + 102 + 110 + 116 + 120 = 631. For 130: all of them, 636.
The result: prepping for 100, close to the average, leaves you $529.32 a Saturday. Prepping for 110 adds about $21 a day. Going from 110 to 120 adds only $1.47 a day while throwing away 44 more crepes' worth of prep over six Saturdays, and at 130 profit falls again. The curve is flat between 110 and 120, so 110 is the sensible pick: almost the same profit, half the bin.
If your prepped cost were higher or your price lower, the best quantity would move down toward the average. That is why both numbers have to be yours.
From the log to the mixing bowl
For each type of day, write down the quantity that pays best and review it every month with the new days. The night before, check the forecast, pick the row and prep that. If your batter recipe is written for 40 crepes, the recipe scaler gives you the quantities for 110.
The same goes for buying: each day's quantity sets the week's shopping list. The guide to production planning helps you turn those quantities into a weekly plan, and the street food and market stall guide puts this together with the rest of the stall's numbers.
Do it with the calculator
Put your recipe into the food cost calculator to get the cost of each crepe. Then split what gets thrown away if unsold (batter, cut fruit, cream) from what you only spend when you sell (plate, napkin, spread), and use those two numbers to build the table above with your own days.
Frequently asked questions
How many days of records do I need before this works?
Four to six days of each type, such as dry Saturdays, is enough to start comparing quantities. The more days you log, the less one odd day can mislead you.
What if I sold out early?
Write down the time you sold out. That day you sold everything you brought, but demand was higher, so treat the number as a minimum rather than what people wanted.
Is it better to run out or to have leftovers?
It depends on two of your own numbers: what you make on each item sold and what you lose on each item thrown away. If you make much more than you lose, prep a bit above your average.
Should I plan around the weather forecast?
Use it as one more column in your log. Check it the night before, note what the day turned out like, and compare with what you sold on similar days.