What this calculation means
Recorded food-waste costing prices each logged discarded item with its matching purchase unit cost. The total is then compared with food purchases for that same period.
The log may be incomplete. This total is not a measurement of all restaurant waste or lost revenue.
How to use this calculator
Enter same-period food purchases. Add each discarded quantity and the purchase cost per matching unit in paired rows; use the correct unit for each individual item.
Formula and variables
Recorded waste cost = Sum of (Discarded quantity × Purchase cost per unit); Purchase share = Recorded waste cost ÷ Food purchases × 100
- Food purchases in this periodUSD
- Food purchases on the same period and valuation basis as the waste log.
- Discarded item
- Discarded quantity (matching unit) × Purchase cost per unit (USD / matching unit) for each row.
Dollar amounts display to cents, with exact half-cent values rounded away from zero; intermediate calculations keep full precision.
Understand your result
The primary result is the purchase-cost valuation of entered discarded food only. Details show each row’s dollar cost and the total share of matching-period purchases; they do not claim a share of sales or diagnose why waste occurred.
Worked example
A waste log records 3 lb of chicken at $4/lb and 2 qt of dairy at $4.50/qt, against $1,000 same-period food purchases.
Food purchases in this period: 1,000 USD
Discarded item 1: Discarded quantity: 3 matching unit; Purchase cost per unit: 4 USD / matching unit
Discarded item 2: Discarded quantity: 2 matching unit; Purchase cost per unit: 4.5 USD / matching unit
- Chicken discard: 3 lb × $4 per lb = $12. Dairy discard: 2 qt × $4.50 per qt = $9.
- The recorded waste total is $21.
- Against $1,000 food purchases, $21 ÷ $1,000 × 100 = 2.10%.
Example result: $21.00
Frequently asked questions
Can rows use different units?
Yes, if each quantity is matched with the correct unit cost in its own row. Pounds at dollars per pound and quarts at dollars per quart can be summed after each is converted into dollars.
Is its percentage a share of food sales?
No. The denominator is same-period food purchases. A share of purchases must not be labelled a share of sales.
Can recorded waste cost exceed this period’s purchases?
It can if discarded food includes opening inventory. Review the period and valuation before interpreting the ratio. The displayed share is not automatically an error, and it is not proof that all discarded food was purchased this period.