Recipe Says 2 Pounds Trimmed — How Much Do I Buy?

Divide, don't add. A recipe asking for 2 pounds of peeled butternut squash needs 2 ÷ 0.66 = 3.03 pounds of whole squash, not 2 pounds plus a bit. Then round up to whole units, because shops sell squashes, not decimals.

Recipes are written from the cook's side of the cutting board. "Two pounds of peeled, cubed butternut squash." "Three cups of chopped onion." "One pound of trimmed green beans." Shops sell from the other side: whole squashes with skin and seeds, onions in papery jackets, beans with their stem ends on. Somewhere between the recipe and the checkout, somebody has to do a conversion, and getting it wrong is how you end up back at the shop halfway through cooking.

The One Piece of Arithmetic

Every ingredient has a yield percentage: the share of the whole thing that survives peeling, coring, stemming and trimming. Butternut squash is about 66%. Onions are about 89%. A whole head of cauliflower is about 55%, because the leaves and core are most of what you carry home.

To go from a recipe quantity to a shopping quantity you divide by that percentage:

Buy = what the recipe needs ÷ yield percentage

The instinct to add a percentage instead is the mistake worth naming, because it always under-buys and the error gets worse as the yield gets lower. Two pounds of squash plus 34% is 2.68 pounds. Two pounds divided by 0.66 is 3.03. At cauliflower's 55% yield the gap is bigger still: adding 45% to a pound gives 1.45 pounds, dividing gives 1.82, and you are nearly half a head short.

The yield percentage calculator runs this in both directions and carries the price through, if you would rather not do it on your phone at the vegetable aisle.

Then Round to Something You Can Actually Buy

3.03 pounds of butternut squash is a number, not a purchase. Squashes in a supermarket run roughly 2 to 3 pounds each, so this is one large one, or a small one plus most of another. That second step — converting a weight into units on a shelf — is where a chart of typical sizes saves a lot of standing around guessing.

Item	Typical single unit	Yield
Onion, medium	about 4 oz / 110 g	89%
Onion, large	about 5-6 oz / 150 g	89%
Russet potato, medium	about 6 oz / 170 g	81%
Sweet potato, medium	about 4.5 oz / 130 g	80%
Carrot, medium	about 2 oz / 60 g	82%
Celery, one stalk	about 1.5 oz / 40 g	75%
Bell pepper, medium	about 4 oz / 120 g	65%
Tomato, medium	about 4.5 oz / 125 g	91%
Zucchini, medium	about 7 oz / 195 g	95%
Butternut squash	2-3 lb / 0.9-1.4 kg	66%
Broccoli, one head	about 1 lb / 450 g	61%
Cauliflower, one head	about 1.3 lb / 590 g	55%
Lemon, medium	about 3.5 oz / 100 g	3 tbsp juice
Lime, medium	about 2.4 oz / 67 g	2 tbsp juice

Supermarket produce varies enough that these are working estimates, not specifications. Weigh once if the quantity really matters.

Three Worked Examples

Two pounds of peeled, cubed butternut squash. 2 ÷ 0.66 = 3.03 lb as purchased. At 2 to 3 pounds a squash, buy one large one and accept a little spare, or two small ones and roast the rest.

Three cups of chopped onion. Volume first: a cup of chopped onion weighs about 160 g, so three cups is 480 g of prepped onion. Divide by the 89% yield: 480 ÷ 0.89 = 539 g, about 1.2 pounds. At roughly 150 g for a large onion, that is four large onions — noticeably more than the three most people would reach for.

Half a cup of lemon juice. Here the weight route is the wrong route. Juice is measured by volume, and a medium lemon gives about 3 tablespoons. Half a cup is 8 tablespoons, so 8 ÷ 3 = 2.7, meaning three lemons. Yield percentages are for solids; for juice, count fruit.

Trim Loss Is Only the First Loss

Yield percentage stops at the cutting board. If the recipe measures the ingredient cooked, there is a second shrink waiting after it.

Spinach makes the point painfully. A pound of untrimmed spinach loses its stems and coarse leaves first, leaving about 12 ounces. Then it hits the pan and collapses to roughly a quarter of that. A recipe asking for "one cup of cooked spinach" has quietly asked for a bag that looked absurd at the till. Apply the yield percentage first to get to trimmed weight, then apply cooking shrinkage — the raw to cooked weight converter handles that second step for vegetables, meat and grains.

Meat has the same two-stage structure: what the butcher's bone and fat cost you, then what the pan takes. If you are scaling a recipe up for a crowd, both losses scale with it, which is why big-batch shopping lists built by simply multiplying the original tend to come up short.

When the Recipe Doesn't Say Which It Means

"Two cups of chopped tomatoes" is unambiguous — chopped is a prepped state, so that is edible portion. "Two large tomatoes" is as-purchased, and no conversion is needed. The awkward one is "1 pound of tomatoes, chopped", where the comma is doing a lot of work: it usually means buy a pound and chop it, not chop until you have a pound.

The rule that resolves most of them: if the quantity comes before the preparation word, it is as-purchased; if the preparation word comes first, it is edible portion. "1 pound carrots, grated" means weigh then grate. "1 pound grated carrot" means grate then weigh, and you need about 1.2 pounds of carrots to get there. It is a small distinction that changes a recipe's outcome more often than it should.

The Whole-Versus-Pre-Cut Decision

Yield is also the honest way to compare pre-cut produce against the whole thing, and it does not always favour the whole thing. A 3 pound pineapple at $3.99 works out at $1.33 a pound as purchased, and at a 38% yield that is $3.50 for every pound of fruit you eat. Pre-cut pineapple at $5.99 a pound is still the more expensive option, but the real gap is $2.49, not $4.66 — less dramatic than the shelf price suggests.

Run the same sum on something with a high yield and pre-cut looks much worse: pre-washed spinach barely beats loose spinach on labour, and loses badly on price per usable ounce. Low-yield, fiddly items are where the convenience premium is closest to fair.

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