Sizu Riatto
Grow by Numbers · Chapter 10

Break-Even

Every pack sold pays back a little of the kit. Divide the kit by what each pack or tray contributes, round up, and you know how many to sell; divide by your weekly sales and you know how long.

Home › Calculators › Break-Even

Opens on the book's Microgreen Shelf. Change any number to your own and press Calculate.

The kit (fixed costs)

Your crops: harvest a tray and the cost to grow it (from the cost-per-tray calculator)

The pack and your selling rate

Enter the kit, your crops and your price, then press Calculate.

The formula

  • Fixed costs = the kit (+ a year of insurance, if you sell)
  • Cost of a pack = growing cost per gram × pack grams + clamshell and label
  • Contribution a pack = price − cost of a pack; a tray = its packs × (price − packing) − its cost to grow
  • Break-even = fixed costs ÷ contribution, rounded up (SBA)
  • Weeks = break-even packs ÷ packs a week, rounded up
The book's worked example, Chapter 10. The kit: shelf 85, four lights 80, 16 trays 96, timer 10, GFCI adapter 32, scale 16, sprayer 5 = 324. A 2 oz pack costs about 1.00 all in and sells at 5: it contributes 4.00. The average tray sold contributes 21.27, so break-even is 16 trays (81 packs, about 7 weeks at 12 packs a week); with a year of insurance (299), 30 trays.
Check it. Multiply the break-even count by the contribution: it should just pass the fixed costs, and one fewer should fall just short.

Honest limits. A worked example with illustrative prices, not a promise of sales: buyers, waste and the weather decide. Register and insure before you sell where the rules require it (Chapter 10's Stop Line). The Microgreen Shelf was worked out on paper from published figures, not grown by us: weigh and measure your own. Prices are illustrative US prices from October 2026, shown without a currency sign; put in your own. Everything stays in your browser: no sign-up, nothing stored.

These calculators go with Grow by Numbers (Make It Add Up, Book 1), where every number on this page is worked by hand.