Unit Price Calculator

Compare two products by price per unit to find the better deal.

Product 1

Price ($)

Quantity

Unit

Product 2Better Deal

Price ($)

Quantity

Unit

Results

Product 1 per g

$0.0080

Product 2 per g

$0.0072

Product 2 is cheaper by $0.0008 per g.

How to compare unit prices

Unit price = total price ÷ quantity. Comparing by unit price lets you cut through "buy 2 get 1" promotions and odd pack sizes to find the true cheaper option. Common units: g, kg, oz, lb, mL, L, count. Enter the same unit for both products for a fair comparison; if units differ (e.g. 500 g vs 1.1 lb), convert first using the grams to ounces converter.

Built and maintained by Meet Shah · Last updated 19 July 2026

What this tool is used for

Comparing two package sizes on price per unit.
Checking whether a larger pack is actually cheaper.
Comparing products sold in different units.
Working out the cost per serving or per use.
Checking a shelf label's unit price rather than trusting it.

Frequently Asked Questions

Does it convert between units?: No — the unit box is a label, not a conversion. Price is divided by quantity exactly as typed, so putting 500 g against 1 lb compares grams with pounds and crowns the wrong winner. Convert both to the same unit first, then compare.
Why do both products show the same unit price?: The figures are rounded to four decimal places, and at $0.00801 versus $0.00799 per gram both display as 0.0080. Enter the quantity per 100 g or per litre instead, so the digits that differ land somewhere you can actually read them.
Is the bigger pack always cheaper per unit?: Often, but not reliably. Retailers regularly price a promoted small pack below the family size, which is exactly why unit-price labelling is mandatory under EU Directive 98/6/EC and in most US states. Checking costs one division.
What should I put in the quantity box?: Whatever your comparison should rest on: grams, millilitres, sheets, servings, washes. For tinned food use the drained weight rather than the net weight, and for a concentrate use the made-up volume rather than the size of the bottle.
How is the saving figure calculated?: It is the gap in price per single unit, not per pack. Between 0.0080 and 0.0072 per gram the difference is 0.0008 — which is $0.72 across a 900 g pack. Multiply the per-unit gap by the quantity you actually buy to see real money.
Why is the bigger pack not always cheaper per unit?: Because pack pricing follows demand and shelf strategy rather than volume discount — the middle size is frequently the worst value. Comparing unit prices rather than assuming scale is the entire point of doing the arithmetic.

Common errors and gotchas

Comparing per-item against per-weight, which are not the same measure.
Overlooking that the larger pack is only cheaper if you use all of it.
Ignoring differing concentrations, where two products need different amounts per use.
Comparing a promotional price against a regular one.
Rounding the unit price so heavily that a real difference disappears.