Unit price calculator
FinanceNo. 74 / 84
Compare two products by price per gram, liter or item, because the bigger box is not always the better deal.
the big box is only a bargain if the math agrees. the math is right here.
work surface
Math, not advice — results are indicative.Read the disclaimer.
most-used utilities
Rice in bulk
The 5 kg sack against the 1 kg bag — the pantry decides, the math nominates.
Coffee beans
A 250 g bag against a 1 kg bag, where the difference per cup is real money.
Shampoo shelf
400 ml against 1 l, with the pump bottle pretending to be a bargain.
pro tips
Compare within the same family. Grams against ounces is fine; grams against milliliters is a density question wearing a price tag.
Shelf labels usually pick a base unit that flatters the product. Divide both packs by the same amount before you believe the yellow tag.
A lower unit price is not a saving if the extra pack spoils. Cheap per gram, expensive per bin bag.
what it does
Type a price and an amount, pick grams, kilograms, milliliters, liters, ounces, pounds or plain items, and the widget turns it into a price per unit — plus the friendlier shelf numbers: per 100 g, per 1 kg, per 100 ml or per 1 l. Add a second product and it tells you which one is actually cheaper.
This is the supermarket argument settled in one screen: the 5 kg bag of rice against the 1 kg bag, the family shampoo against the travel bottle, coffee beans in a tin against coffee beans in a bag. It also works for online listings, where the pack size hides in the third photo and the price looks innocent.
A real pair: 500 g of coffee for $3.49 works out at $0.698 per 100 g. A 1 kg bag for $6.29 is $0.629 per 100 g, so the bigger bag is about 10% cheaper per gram. That is $0.07 less for every 100 g, which adds up faster than the loyalty card.
Ounces and pounds are converted to grams, liters and milliliters to the same base, so mixed labels behave. Weight and volume never compare directly, though — a liter of oil is not a kilogram of flour unless you know the density. The widget ignores quality, shipping and the half pack that goes stale in the cupboard.
quick answers
What is a unit price?
The price divided by the amount you get, expressed per gram, per milliliter or per item. It is the only number that lets two different pack sizes stand on the same shelf.
Can I compare ounces with grams?
Yes, both measure weight, and the widget converts them automatically. Fluid ounces are volume, though, so they only compare with milliliters, not with ounces on a scale.
Why does the store show a different unit price?
Stores pick their own base — per 100 g, per kilogram, per ounce — and round the result. Promotions and taxes land on the shelf price, not always on the unit price, so the tag can disagree with the receipt.