The one move behind almost every problem here: turn ounces into a fraction of a pound by dividing by 16, then multiply by the price per pound. Beef at $6 a pound with a 6-ounce serving is 6 ÷ 16 = 0.375 lb, and 0.375 × $6.00 = $2.25.
Cost per serving problems turn up in culinary arts, consumer math and family and consumer science classes, and they almost always come in the same shape: a price per pound, a serving size in ounces, and an instruction to round to the nearest cent. The problems below start with exactly that shape and then add the twists textbooks use to make them harder — packages, trim loss, whole recipes and menu pricing.
The Formula
Cost per serving = (serving ounces ÷ 16) × price per pound
Dividing the price by 16 first to get a price per ounce gives the same answer, but it tempts you to round the price per ounce to cents and carry that rounding forward. Converting the serving instead keeps the numbers exact until the last step, which is the only place rounding belongs.
Level 1: Price Per Pound, Serving in Ounces
You purchase beef at $6 per pound. Each serving uses 6 ounces. What is the cost per serving?
6 ÷ 16 = 0.375 lb. 0.375 × $6.00 = $2.25 per serving.
You purchase potatoes at $1.60 per pound. Each serving requires 8 ounces. What is the cost per serving?
8 ÷ 16 = 0.5 lb. 0.5 × $1.60 = $0.80 per serving.
You purchase butter at $3.20 per pound. Each serving requires 2 ounces. What is the cost per serving?
2 ÷ 16 = 0.125 lb. 0.125 × $3.20 = $0.40 per serving.
You purchase cheese for $4 per pound. Each serving uses 4 ounces. How much does the cheese cost per serving? Round to the nearest cent.
4 ÷ 16 = 0.25 lb. 0.25 × $4.00 = $1.00 per serving.
Chicken breast costs $3.49 per pound. Each serving is 5 ounces. What is the cost per serving, to the nearest cent?
5 ÷ 16 = 0.3125 lb. 0.3125 × $3.49 = $1.0906…, which rounds to $1.09 per serving. This is the first one where rounding actually matters, and why it should wait until the end.
Level 2: Packages and Number of Servings
A 2-pound box of pasta costs $3.18. Each serving is 2 ounces. How many servings are in the box, and what does each cost?
2 lb × 16 = 32 oz. 32 ÷ 2 = 16 servings. $3.18 ÷ 16 = $0.19875, which rounds to $0.20 per serving.
A 5-pound bag of rice costs $6.40. A serving is 1.5 ounces of dry rice. What does a serving cost?
5 lb × 16 = 80 oz. 80 ÷ 1.5 = 53.33 servings — the bag holds 53 full servings with a little left over. Cost per serving is easier from the fraction instead: 1.5 ÷ 80 = 0.01875 of the bag, × $6.40 = $0.12 per serving. Dividing $6.40 by a rounded 53 would give $0.1208, the same to the cent here, but not always.
Level 3: When Part of What You Buy Is Thrown Away
Harder problems add a yield percentage — the share of the purchase that is usable after peeling, trimming or boning. The price per pound you paid covers the waste too, so the real price of the usable part is higher. Divide the price by the yield as a decimal before doing anything else.
Whole broccoli heads cost $1.80 per pound and yield 61% usable florets. Each serving is 3 ounces of florets. What is the cost per serving?
Usable price: $1.80 ÷ 0.61 = $2.9508 per pound of florets. 3 ÷ 16 = 0.1875 lb. 0.1875 × $2.9508 = $0.5533, so $0.55 per serving.
Ignoring the yield gives 0.1875 × $1.80 = $0.34 — off by more than a third.
Pineapple costs $2.00 per pound and has a 38% yield. A serving is 5 ounces of fruit. What does a serving cost?
$2.00 ÷ 0.38 = $5.2632 per usable pound. 5 ÷ 16 = 0.3125 lb. 0.3125 × $5.2632 = $1.6447, so $1.64 per serving.
Yield figures for 51 fruits and vegetables are in the yield percentage calculator, which also does this division for you.
Level 4: A Whole Recipe, Then Food Cost Percentage
A pot of chili uses the ingredients below and makes 8 servings. What is the cost per serving?
| Ingredient | Amount and price | Cost |
|---|---|---|
| Ground beef | 2 lb at $5.49/lb | $10.98 |
| Kidney beans | 2 cans at $1.09 | $2.18 |
| Crushed tomatoes | 1 can, 28 oz | $2.29 |
| Onion | 0.5 lb at $1.20/lb | $0.60 |
| Spices | estimated | $0.75 |
| Total | $16.80 |
$16.80 ÷ 8 = $2.10 per serving. You always divide by the number of servings the recipe yields.
A café sells that bowl of chili for $8.50. What is the food cost percentage?
$2.10 ÷ $8.50 = 0.2471, so 24.7%. The smaller number always goes on top; $8.50 ÷ $2.10 = 4.05 is a markup, not a percentage.
The owner wants a 28% food cost on the chili. What should the menu price be?
$2.10 ÷ 0.28 = $7.50. That is the lowest price that hits the target; the café's current $8.50 beats it.
Common Mistakes
Multiplying pounds by ounces. $6 per pound × 6 ounces = $36 is the price of six pounds. If the answer is bigger than the price per pound for a serving smaller than a pound, a conversion was skipped.
Using 12 or 10 instead of 16. A pound is 16 ounces. Nothing else in a US kitchen is, which is why the slip is common.
Rounding in the middle. Rounding $3.49 ÷ 16 to $0.22 per ounce and multiplying by 5 gives $1.10; the exact answer is $1.09. Keep every digit until the last step.
Forgetting the yield. If a problem gives a yield percentage, it is there to be used, and it always makes the cost go up.
Dividing the wrong way for food cost. Food cost percentage is cost ÷ price, never price ÷ cost.
More Practice
The kitchen math problem generator makes fresh problems of each type here, including yield-adjusted cost and food cost percentage, with the working shown when you ask for it. The cost per serving calculator checks any answer you get, and culinary math formulas has every formula on one page.
Frequently Asked Questions
You purchase beef at $6 per pound. Each serving uses 6 ounces. What is the cost per serving?
$2.25. Six ounces is 6 ÷ 16 = 0.375 of a pound, and 0.375 × $6.00 = $2.25.
How do you calculate cost per serving when the price is per pound and the serving is in ounces?
Convert the serving to pounds by dividing the ounces by 16, then multiply by the price per pound. Round to the nearest cent only at the very end.
A recipe yields 8 servings. What number do you divide the total cost by to find the cost per serving?
8 — the number of servings the recipe yields. Cost per serving is total recipe cost divided by the number of servings.
What is the most common mistake in cost per serving problems?
Mixing pounds and ounces without converting. Multiplying $6 per pound by 6 ounces gives $36, the cost of 6 pounds. Divide the ounces by 16 first.