Cost per serve: the only supplement number I really care about

Sticker price tells you what leaves your bank account. Cost per serve tells you whether it was worth it. Here's how I work it out.

By Dan Armstrong · 10 July 2026

If you take one thing away from this whole site, make it this: compare cost per serve, not price. It's the single change that saves people the most money, and it takes about five seconds once you know the formula.

The formula

Cost per serve = total price ÷ servings per container

That's it. No weighting, no fudge factors. We use exactly this on every product page so the number you see here matches the one you'd work out yourself with a calculator.

A worked example

Say you're staring at two whey tubs on different sites:

• •Tub A — $69.95, 1kg, 33 serves → $2.12 per serve
• •Tub B — $109.95, 2kg, 66 serves → $1.67 per serve

Tub A looks $40 cheaper. Tub B is 21% cheaper per scoop. Over a year of five shakes a week, that gap is worth well over a hundred bucks. The bigger tub almost always wins on maths — the only question is whether you'll actually get through it before you're sick of the flavour.

Protein has a second number

For protein powders I also look at cost per 100g of protein, because scoop sizes and protein percentages vary wildly between a WPI and a blend. A cheap serve of a 60%-protein blend isn't the same product as a pricier serve of a 85% isolate. Both numbers show up on the protein buyer guide.

Where cost per serve can mislead you

1. 1.Under-dosed products. A pre-workout with 150mg of caffeine and one with 350mg aren't comparable serves, even if the per-serve cost matches. Check the label breakdown on the product page.
2. 2.Serving sizes the brand chose to flatter itself. Some brands quote a half scoop as a serve. If the serve size in grams looks small relative to the tub, that's a hint.
3. 3.Products you'll never finish. Best value on a 5kg bag is irrelevant if two kilos go stale in the cupboard.