Unit price calculator: price per ounce, pound and item

Compare grocery prices by the ounce

A bigger box usually looks like the better deal, but the only fair way to compare two sizes is the unit price: the price per ounce, per fluid ounce, per pound or per item. Shelf tags often show it in small print, but rarely account for a "buy 2, get 1 free" deal. Enter the price and size of each product and it shows the price per unit, ranks the products from cheapest to most expensive and tells you how much you save.

How to use it

1. For each product, fill in "Price paid", "Size" and "Unit": oz, lb, fl oz, g, kg, mL, cL, L or item. "Name (optional)" helps you spot it in the ranking.
2. For a multipack such as 6 × 12 fl oz, enter 12 fl oz and put 6 in "Number in pack".
3. If there is a deal, pick it under "Deal": "Free items (buy 2 get 1, 3 for 2…)", "2nd item 50% off (or other %)" or "Percent off".
4. Use "Add a product" to compare up to 10 items. Change the "Currency", the "Unit price shown" (per ounce, per kg and liter, or per 100 g and 100 mL) and the amount in "Savings calculated for" if needed.

Worked examples

16 oz or 24 oz?

A 16 oz jar at $3.99 costs 3.99 ÷ 16 = $0.249 per oz. A 24 oz jar at $5.49 costs $0.229 per oz. The small jar is 9.0% more expensive per ounce. For 1 lb (16 oz), the large jar saves you $0.33, or 8.3% of the higher unit price.

Buy 2, get 1 free

A 14.1 oz box at $2.40 with "buy 2 get 1 free": you pay 2 × $2.40 = $4.80 for 3 boxes, so the price per box drops to $1.60 and the unit price falls by a third. Enter "Buy" 2 and "Get free" 1 and the tool divides what you pay by everything you take home.

Second item 50% off

Two 64 fl oz bottles at $3.84 with the second one 50% off cost $3.84 + $1.92 = $5.76 for 128 fl oz, that is $0.045 per fl oz instead of $0.06 for a single bottle.

Price per item

Common traps

• Bigger isn't always cheaper. A sale on the smaller size can flip the ranking. Only the unit price settles it.
• Drained weight. For canned vegetables, beans or tuna, compare the drained weight, not the net weight with the liquid. A can sold by net weight can cost far more per ounce of food than the shelf tag suggests.
• Ounces and fluid ounces are different units. An ounce is a weight; a fluid ounce is a volume. The calculator ranks weight, volume and per-item products in separate groups.
• Different units on the shelf. One tag may show the price per ounce and the next the price per pound or per quart. Enter both products here to see them in the same unit.
• Deals only count if you buy the whole set. One box from a "buy 2 get 1 free" offer is full price.

FAQ

How do I calculate the price per ounce?

Divide the price by the number of ounces. A 20 oz bag at $4.00 costs 4 ÷ 20 = $0.20 per oz. For pounds, multiply the price per ounce by 16.

Why does the result show three decimals?

Unit prices under one dollar are shown to a tenth of a cent, like many shelf tags, so that close products don't look identical.

How are the savings worked out?

The tool takes the gap in unit price between the cheapest and the most expensive product and multiplies it by the amount in "Savings calculated for". The percentage is that gap divided by the higher unit price.

Can I use it in metric units?

Yes. Choose g, kg, mL or L for each product and set "Unit price shown" to per kg and liter or per 100 g and 100 mL. You can mix ounces and grams: the tool converts them.