By Heidi Macomber · July 26, 2026 (updated July 31, 2026)

If you don't know what each portion of food costs you to make, every price on your menu is a guess. Here's the cost-per-portion formula, why most owners calculate it wrong, and how to get it right without spending your Saturday in a spreadsheet.

The Cost Per Portion Formula

Here it is:

Cost per portion = Total recipe cost ÷ Number of portions the recipe yields

That's the whole formula. Total cost of all ingredients in a batch, divided by how many servings you get out of it.

If a batch of chili costs you $24.50 to make and yields 10 bowls, your cost per portion is $2.45.

The formula is simple. What trips people up is getting the two numbers right.

Where the Math Goes Wrong

The formula has two inputs and owners blow both of them regularly.

Problem 1: Your total recipe cost is too low

You buy a 40-pound case of chicken thighs for $1.89 a pound. Your recipe calls for 6 ounces of chicken per sandwich. So you divide $1.89 by 16 ounces, multiply by 6, and call it $0.71.

That number is fiction. You bought raw, bone-in thighs. You serve trimmed, cooked meat. Between trimming fat and cooking off moisture, you lose about 30% of what you paid for. To get 6 ounces of cooked chicken on the plate, you had to start with roughly 8.5 ounces of raw product.

Your real chicken cost on that sandwich is about $1.00, not $0.71.

This is the AP versus EP problem, and it's the most common costing mistake in food service. AP (As Purchased) is what you paid for. EP (Edible Portion) is what actually reaches the plate. If your recipe cost uses AP prices but your portions are listed in trimmed or cooked amounts, every portion cost on your menu is understated and you don't know it.

The same thing happens with produce. A case of onions doesn't yield 100% usable onion. You peel it, trim the ends, lose the outer layers. A head of romaine loses nearly a third of its weight when you strip the outer leaves and core it.

Problem 2: You don't know your actual yield

The second input: number of portions: sounds easy. A recipe makes 10 servings. Except it doesn't. It makes 10 servings when your prep cook portions carefully. It makes 8 when someone's in a hurry and using a bigger ladle. It makes 12 when business is slow and they're stretching it.

Portion inconsistency destroys portion costing. If your recipe says it yields 10 portions but your line actually serves 9, your real cost per portion is higher than your formula says. You're pricing against a number that doesn't exist.

This is why standardized portioning matters. Scoops, ladles, and portion cups aren't just for consistency on the plate. They're what make your cost-per-portion formula accurate. If your team free-pours or eyeballs portions, your actual yield is a moving target and so is your cost.

A Worked Example: Costing a Burger

Let's run the full formula on a bacon cheeseburger.

First, cost out every ingredient in the batch. Say your recipe makes 20 burgers.

Now divide by your yield:

$42.95 ÷ 20 portions = $2.15 per portion

That's your cost per portion. If you sell the burger for $11, your food cost percentage is about 19.5%. That's a healthy margin for most operations.

But notice what had to happen to get there. The beef cost had to reflect cooked yield, not raw invoice price. The bacon had to be costed as cooked strips, not raw weight. The sauce had to be included even though it feels small. Leave any of those out and your portion cost drifts, and so does your pricing.

Cost Per Portion vs. Cost Per Plate

People ask whether this is different from plate costing. It's the same concept, narrower in focus.

Plate costing includes everything that goes into serving a dish: ingredients, packaging, sometimes a waste factor. Cost per portion is the core ingredient calculation underneath that. It's the raw food cost divided by portions.

You need both. The portion cost tells you what the food itself costs. The plate cost adds the extras. But you can't get to an accurate plate cost without an accurate portion cost first.

Portion Costing for Recipes That Don't Portion Cleanly

Not every recipe divides neatly into identical servings. Soup, sauce, casserole, anything scooped or ladled: the yield depends on how you portion it.

For these, use weight or volume instead of count.

Say a batch of marinara costs $18.40 and weighs 9 pounds finished. Your portion is 4 ounces per plate. Cost per portion:

($18.40 ÷ 9 lb) × (4 oz ÷ 16 oz/lb) = $0.51 per portion

Or in volume: if the batch yields 180 fluid ounces and you serve 2 ounces per plate, your yield is 90 portions. Divide the batch cost by 90.

The method stays the same. Total cost divided by yield. You just have to be honest about what a portion actually is and measure it consistently.

Common Portion Costing Mistakes

Leaving out the cheap stuff. The pinch of salt, the spray of oil, the garnish. Each one is pennies. Across a few hundred covers a day, those pennies are rent. If your portion cost doesn't include cooking fat and seasoning, it's too low.

Using supplier prices from three months ago. You costed your menu in March. Your beef distributor raised prices 14% in May. If you didn't update the recipe, you're pricing against stale numbers. Check your top five ingredients monthly. Prices move and your portion costs have to move with them.

Ignoring shrinkage on proteins and produce. Covered above, but it's worth repeating because it's the single biggest source of wrong numbers. Anything you trim, peel, bone, or cook loses weight. Use EP cost, not AP cost.

Not accounting for waste and over-portioning. If your line consistently serves 6.5 ounces when the recipe says 6, your real portion cost is higher than your formula says. Weigh what actually goes on the plate, not what the recipe card says should go on it.

How Often Should You Recalculate?

Monthly for your top sellers and anything protein-heavy. Full menu recosting every quarter is a reasonable rhythm for most small operations. Anytime a supplier hands you a price increase, update that ingredient the same week.

If you're adding a new item, cost it before it goes on the menu. Not a month after you've been selling it at a price you made up.

Doing This Without Losing Your Weekend

You can run this formula in a spreadsheet. Plenty of owners do. It works until your menu grows past a dozen items, or a supplier changes one price and you have to recalculate it across fifteen recipes by hand.

Percy Plate handles the parts that make portion costing painful manually:

• Ingredient costs with automatic unit conversions, so you can buy by the pound and recipe by the ounce without doing the math
• Yield and trim adjustments so your portion costs reflect what reaches the plate, not what came off the truck
• Recipe-level costing that updates across your entire menu when one ingredient price changes
• Portion-level cost shown against your menu price, so you see immediately when an item drifts out of your target range

The point isn't tidier spreadsheets. It's knowing the real cost of every portion you serve so you can price with confidence instead of crossing your fingers.

Start With One Recipe

Don't try to cost your whole menu today. Pick your best-selling item. List every ingredient. Look up what you actually pay per unit, accounting for trim and cooking loss on any protein. Add it all up. Divide by your real portion count.

Compare that number to what you charge.

That first comparison is often a gut punch. It's also the most useful twenty minutes you'll spend on your business this week. Once you know your true cost per portion, every pricing decision gets easier: and a lot less of a gamble.

Related Guides

• Burger Cost Calculation: How Much a Burger Actually Costs You to Make — See AP/EP costing applied step by step to a real burger recipe
• How to Cost a Plate of Food: The Complete Guide — Full plate costing from ingredient to menu price
• Recipe Costing 101 — How to cost out any recipe for profit
• Consignment Pricing for Cottage Bakers: What to Charge When the Shop Takes 20% — what the shelf price must be after a shop's 20% cut

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