Cost Per Serving Worksheet
Measure your waste once per ingredient and the rest is arithmetic. Compare on edible weight, not on the shelf label.
BFCBrilliance · bfcbrilliance.com/tools/grocery-cost-per-serving-calculator
Ingredients
| Ingredient | Price | Pack weight | Waste % | Serving | Cost/serving |
|---|---|---|---|---|---|
The arithmetic
- Edible weight
- pack weight x (1 − waste %)
- Servings per pack
- edible weight ÷ serving size
- Cost per serving
- price ÷ servings per pack
- Cost per 100 edible
- price ÷ edible weight x 100
- Packages to buy
- servings needed ÷ per pack, ROUNDED UP
- ⚠ Shelf unit price
- uses PACK weight — flatters waste
What waste does to the price
- 10% waste
- cost x 1.11
- 20% waste
- cost x 1.25
- 25% waste
- cost x 1.33
- 30% waste
- cost x 1.43
- 40% waste
- cost x 1.67
- 50% waste
- cost x 2.00
- 60% waste
- cost x 2.50
- 75% waste
- cost x 4.00
- The rule
- 1 ÷ (1 − waste), NOT 1 + waste
Measure your own waste
- Ingredient
- Weight as bought
- Weight after preparing
- Difference
- WASTE %
- Date measured
Getting an honest number
- Pack weight and serving size in the SAME unit
- Waste measured on your own kitchen scale, not looked up
- Serving size is what reaches the plate, not what you started with
- Compared on EDIBLE weight, not the shelf unit price
- Leftover from a bulk pack counted only if it gets eaten
- Spoilage included in waste for anything you regularly bin
- Whole packages costed for what you SPEND
- Same comparison run for the alternative product
30% waste is a 43% price rise
Not 30%. The edible part is 70% of the weight and carries all of the price, so the cost per edible gram is 1 ÷ 0.7 = 1.43. It accelerates: 50% waste doubles the cost and 75% quadruples it. Use 1 ÷ (1 − waste), never 1 + waste.
Bulk is only cheaper if you eat it
A large pack at a lower unit price that half rots is more expensive than a small pack at a higher one. That is why 'what you spend' and 'what you use' are separate lines - the difference between them is food sitting in your fridge, and it only becomes a saving when it becomes a meal.