Unit Price Calculator
Compare two or three products by the price of a single unit, even when they are sold in different pack sizes and different units. The calculator converts everything to a common unit, shows the price per kilogram, pound, litre or item, and names the best value.
Optional. For a 6-pack, enter 6.
Optional. For a 6-pack, enter 6.
Optional. For a 6-pack, enter 6.
Result
Enter a price and a quantity for products A and B.
The calculation runs in this browser tab. Nothing you enter is uploaded, saved or logged.
What is a unit price and why compare it?
The unit price is the price of one standard unit of a product: per kilogram, per litre, per item. The pack price tells you what you pay today; the unit price tells you what you pay for what you get, which is the only fair way to compare packs of different sizes.
The larger pack is not always the cheaper one, and a product on offer can cost more per unit than another brand at full price. Comparing is made harder when packs use different units (500 g against 1.2 kg, or ounces against grams). The calculator converts both to the same base, so 500 g at 3.49 and 1.2 kg at 6.20 can be compared directly.
How to use the Unit Price Calculator
- Enter the price, the quantity per pack and the unit for product A and product B. Add product C if you want a third.
- If a product is sold as a multipack, enter how many packs: six cans of 330 mL is a quantity of 330 mL and 6 packs.
- Read the best value at the top, followed by the price per unit of each product.
- The table shows each product per kilogram and per pound (or per litre and per 100 mL, or per item and per dozen) and how much more each costs than the best.
Formula
- Total amount
- amount = quantity per pack × number of packs, converted to kg, litres or items
- Unit price
- price per unit = pack price ÷ total amount
- Compared with the best
- % more = (unit price ÷ lowest unit price − 1) × 100
- Saving
- saving = (1 − lowest unit price ÷ highest unit price) × 100
The conversion factors are exact: 1 lb = 0.45359237 kg and 1 US gallon = 3.785411784 litres.
Prices are in your currency and shown to four decimals, because the unit prices of cheap products differ in the third decimal.
Worked example
A 500 g pack at 3.49 against a 1.2 kg pack at 6.20. These are the results the calculator gives:
| Question | Result |
|---|---|
| Input: Product A – price | 3.49 |
| Input: Product A – quantity per pack | 500 |
| Input: Product A – unit | grams (g) |
| Input: Product B – price | 6.20 |
| Input: Product B – quantity per pack | 1.2 |
| Input: Product B – unit | kilograms (kg) |
| Input: Product C – unit | kilograms (kg) |
| Best value | Product B |
| Product A, per kg | 6.9800 |
| Product B, per kg | ≈ 5.1667 |
| Saving per unit, best versus most expensive | 26.0% |
Assumptions and limits
- All products must be measured by the same kind of unit: weight, volume or count. You cannot compare a price per kilogram with a price per litre.
- The calculator compares price only. It does not account for quality, brand, waste, how much you will actually use, or whether you have room to store a big pack.
- Cheap per unit is not cheap if part of a large pack is thrown away; consider shelf life before buying in bulk.
- Fluid ounces are US fluid ounces, and gallons US gallons. Imperial volumes are not offered here: convert them to litres first.
Frequently asked questions
How do I calculate the unit price?
Divide the price by the quantity. A 500 g pack at 3.49 costs 3.49 ÷ 0.5 = 6.98 per kilogram. Compare that with another product’s price per kilogram.
Is the bigger pack always cheaper per unit?
No. Larger packs are often cheaper per unit, but not always, and promotions on small packs can reverse it. Only the unit price shows which is really cheaper.
How do I compare products sold in different units?
Convert them to the same unit first. This calculator does it for you: enter each quantity in the unit on its label, such as grams and ounces, and it compares them per kilogram and per pound.
How do I handle multipacks?
Enter the quantity of one item and the number of packs. A 6-pack of 330 mL cans is 330 mL with 6 packs, for a total of 1.98 litres.
What does “% more” mean in the table?
How much more a product costs per unit than the cheapest one: 35.1% more means the unit price is 1.351 times the best price.
Why compare per 100 g or per 100 mL?
Some shops show prices per 100 g or per 100 mL on the shelf, so the table includes it. It is the same comparison as per kilogram or litre, with the decimal point moved.