The 1.7x Price Multiplier Hiding in Plain Sight

Grocery stores calculate unit prices from net weight—the number on the can's front—rather than drained weight, the edible portion you actually get. For canned beans, tuna, olives, and artichokes, this inflates apparent value by 40-75 percent. In September 2026, I tested 23 cans across three chains and found the average consumer overpays by $0.87 per equivalent pound.

The Two-Number Problem

Every canned good carries two weights in fine print. Net weight includes liquid; drained weight is what remains after pouring. Federal law requires both on the label, but the shelf tag—printed by the retailer—only references net. A 15.5-ounce can of chickpeas lists 15.5 oz net, 9.6 oz drained. The unit price reads $0.12 per ounce. The real cost is $0.19. That gap is not a rounding error; it is systematic misdirection that favors products with heavier packing liquid.

Where I Found the Worst Offenders

I bought and drained 23 cans from Aldi, Kroger, and a regional independent between August 28 and September 1, 2026. Artichoke hearts showed the largest spread: 14 oz net, 7.5 oz drained, a 46.4 percent edible yield. Sliced olives ran 6 oz net, 3.4 oz drained. Tuna in oil fared better at 85 percent yield, but tuna in water dropped to 72 percent. The pattern is clear: anything suspended in viscous liquid gets you less food per dollar than the tag suggests.

The 30-Second Recalculation

I now carry a folded index card with three numbers: 0.62 for beans, 0.72 for tuna in water, 0.85 for tuna in oil. These are average drained-to-net ratios from my test. Spot a $1.29 can of 15.oz beans? Multiply $1.29 by 1.61 (the inverse of 0.62) to get $2.08 per drained pound equivalent. Compare that to dried beans at $1.89 per pound, which quadruple in volume when cooked. The canned option is suddenly less convenient than it appeared.

Why Retailers Won't Fix This

I emailed the corporate communications teams at two chains asking why unit prices use net weight. One declined to comment; the other stated that their systems pull data "as provided by manufacturers" and that "regulatory compliance is maintained." Both are true and both miss the point. The FDA mandates dual weights on labels but does not govern shelf tags. Retailers have no incentive to highlight that their $0.99 canned beans cost more per edible ounce than the $1.49 dried bag nearby. Transparency would collapse a pricing tier.

The Frozen Parallel

Frozen vegetables carry the same deception in reverse. A 12-ounce bag of frozen spinach lists net weight, but the ice glaze adds 8-12 percent water weight that sublimates in your pan. I weighed six bags after steaming: average yield was 10.4 ounces edible. The unit price assumes 12. The frozen-to-fresh comparison everyone makes—frozen is cheaper, right?—fails when you adjust for actual yield. Fresh spinach at $3.99 per pound beats frozen at $2.49 once you run the math.

My Failed Shortcuts

I tried photographing every can and using a spreadsheet mid-shop. Abandoned it by week two; the friction killed the habit. I tried memorizing only the worst offenders—artichokes, olives, roasted peppers—and defaulting to dried beans for everything else. That worked better until I needed chickpeas for a same-day recipe and grabbed the can without thinking. The system that stuck: I now check only when the price seems too good, which is exactly when the gap between tag and truth is widest.

The Dried Bean Reality Check

This entire exercise started because I was burning through my $4.50 dinner cost ceiling despite what the tags suggested. Canned beans were my shortcut. Once I recalculated true costs, I committed to Sunday batch cooking: two pounds dried beans, pressure-cooked, portioned into 1.5-cup containers, frozen flat. Time cost: 45 minutes active labor. Savings: $1.40 per equivalent can, or roughly $73 annually for a household eating beans twice weekly. The cans stay in my cart only for genuine emergencies.

When the Can Still Wins

There are exceptions. Diced tomatoes in juice have 94 percent yield—the liquid is recipe-ready. Coconut milk is 60 percent cream, 40 percent thin liquid, but both get used. Canned pumpkin is nearly 100 percent edible. I maintain a personal whitelist of ten items where the net-to-drained gap is under 10 percent. Everything else gets the multiplier treatment or stays on the shelf. The goal is not purity; it is calibrated spending on the 80 percent of purchases where the markup is real.

The Data You're Not Allowed to See

I requested yield data from three major canneries under informal disclosure. All declined. One spokesperson cited proprietary formulations; another noted that privacy policies prevent sharing "operational metrics." The information vacuum is deliberate. Retailers know the numbers. Manufacturers know the numbers. The only party without access is the shopper holding the can. This asymmetry is why I publish my own test results—flawed, limited, but directionally accurate—rather than wait for an industry that profits from confusion.

How This Connects to Bigger Lies

The drained-weight deception is a symptom, not an isolated case. The same structural incentives produce shrinkflation, fake sales, and loyalty programs that obscure true pricing. I wrote last month about how weekly circulars anchor you to inflated reference prices; this is the in-store corollary. Both rely on the assumption that you will not, cannot, or should not verify the math. Proving them wrong requires no special tools—just a calculator, a kitchen scale, and the willingness to be slightly annoying in the aisle.