Price per serving versus price per 100 g: compare food packages
Compare package sizes fairly after accounting for edible yield, serving size and the unit printed on the shelf.
How to calculate it
A shelf label may show price per kilogram, per 100 g, per litre, per item or per serving. To compare packages, convert them to the same basis. Price per 100 g = package price ÷ package net grams × 100. Price per serving = package price ÷ servings actually obtained. If one package defines a 30 g serving and another a 40 g serving, their displayed per-serving prices are not directly comparable. Prefer a common mass or a serving size you choose.
Worked example
A 450 g pack costing 9 is 2 per 100 g. A 600 g pack costing 11.40 is 1.90 per 100 g, so the larger pack is cheaper by mass. If you eat 75 g per meal, they provide six and eight full servings respectively, costing 1.50 and 1.425 per meal before any waste. If you cannot use the extra 150 g before it spoils, the nominal saving can disappear. Check unit conversions before comparing a liquid to a solid.
What can change the result
Net weight may exclude packaging but include inedible peel, bones or cooking water. Drained weight is more relevant for canned foods where liquid is discarded. A bulk discount, coupon or loyalty requirement may affect only one pack. Quality, nutrition, expiry and actual consumption can be more valuable than a small price difference.
Use the calculators and keep reading
Use the unit price calculator with matching units and compare a realistic serving as a separate check. Apply percentage calculations only after identifying the correct original price. The linked bulk-pack guide helps decide when a larger pack truly saves money.
Try the unit price, percentage calculator and read this related article for the context and assumptions.