Unit Price Calculator
Compare packages by per-unit cost — enter price and quantity for each item and the cheapest option stands out at a glance.
Items
| Total price | Quantity | Price per item | |||
|---|---|---|---|---|---|
$ The price you’d pay at the register for this package. | How many items are in the package (e.g. 12 eggs, 4 rolls). | $ Total price divided by quantity, in the same currency. |
- #1Inputs$The price you’d pay at the register for this package.How many items are in the package (e.g. 12 eggs, 4 rolls).Result$Total price divided by quantity, in the same currency.
Why pack size doesn't determine value
The larger pack is not always cheaper per gram. A 500 g jar priced at $4.99 and a 750 g jar at $6.99 look like a straightforward upsell, but the math favors the larger jar (≈$0.998/100 g vs. ≈$0.932/100 g). This calculator lets you stack as many items as you want and shows the per-unit price for each, so the best deal stands out on its own.
How to use it
- Pick a comparison mode at the top: dimensionless quantity, mass (g/kg/oz/lb), or volume (mL/L/fl oz/gal). All rows share the same mode so the unit-price column is apples-to-apples.
- Fill in total price and quantity for each item.
- Add more rows with + Add item. The unit-price column updates as you type.
- Scan the unit-price column — the smallest number wins.
There is no "best buy" badge on purpose. With the rows in front of you, your eye picks the cheapest faster than any summary line could.
Picking a comparison mode
| Product type | Mode | Example |
|---|---|---|
| Dry goods (flour, rice, pasta) | Mass | 500 g of pasta at $2.49 → $4.98/kg |
| Liquids (juice, oil, shampoo) | Volume | 750 mL bottle at $6.49 → $8.65/L |
| Packaged items (eggs, batteries, tissues) | Quantity (no unit) | 12 eggs at $4.20 → $0.35 each |
You can mix units within a mode — enter one item as 500 g and another as 1.2 kg, the calculator converts both to the same base before computing. Switching modes does not clear values you've already entered for the other modes.
Why shelf unit prices sometimes differ from this calculator
Most retailers are required to display a unit price on the shelf label, but several factors can make those labels hard to compare directly:
- Different reference quantities. One label shows price per 100 g; another shows price per kg. This calculator always reports per-kg or per-L so rows compare directly.
- Multi-buy promotions. A "3 for $10" deal changes the effective unit price only if you actually buy three. Enter the promotion total as the price and the combined quantity to check.
- Weight vs. drained weight. Canned goods list net weight including liquid. The drained weight — what you actually eat — is lower and varies by brand.
Bulk buying — when it is and is not worth it
A lower unit price does not always mean you save money in practice:
- Perishables. A five-litre bottle of olive oil is cheaper per litre but costs more if half of it goes rancid before you finish it.
- Storage. Bulk paper towels are genuinely cheaper, but only if you have somewhere to put them.
- Cash flow. A larger upfront spend ties up money that earns interest or covers other expenses.
Use the unit-price comparison as the starting point, then factor in these practical constraints before deciding which size to buy.