Unit price calculator
Unit price = price ÷ quantity. A 500 g pack at 2.49 costs 4.98 per kg, so a 1 kg pack at 4.59 is the better deal.
- Checked on thousands of cases
- Updated November 1, 2026
- Product 1
4.98per kg
- Product 2
4.59per kgBest deal · 8% cheaper
Quick challenge
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Test yourself: every answer is computed by the tool, and the wrong choices are the most common traps.
How it works
Formula: Unit price = price ÷ quantity
For each product, the calculator converts the quantity to kilograms, liters or items, then divides the price by it. Grams, ounces and pounds are compared per kilogram; milliliters, liters and fluid ounces per liter. The cheapest product per unit is highlighted with the saving compared with the most expensive one. Products measured by weight and by volume can't be compared directly.
Worked examples
500 g for $2.49
2.49 ÷ 0.5 kg = $4.98 per kilo.
1 kg for $4.69
$4.69 per kilo: 5.8% cheaper per kilo.
12 eggs for $3.60
$0.30 per egg.
Common mistakes
Comparing shelf prices.
Compare the price per kilo or per liter: the big pack is not always cheaper.
Mixing grams and kilos.
500 g = 0.5 kg: $2.49 means $4.98 per kilo, not $2.49.
Forgetting what you actually use.
A big pack cheaper per kilo saves nothing if it ends up in the bin.
Example: the same product in four sizes
| Size | Price | Price per kg |
|---|---|---|
| 250 g | 1.79 | 7.16 |
| 500 g | 2.49 | 4.98 |
| 1 kg | 4.59 | 4.59 |
| 2 kg | 8.99 | 4.5 |
Frequently asked questions
How do I compare two package sizes?
Divide each price by its quantity in the same unit. 2.49 for 500 g is 4.98 per kg; 4.59 for 1 kg is 4.59 per kg, so the larger pack is cheaper.
Is the bigger pack always cheaper?
No. Promotions on small sizes or packaging costs can make the smaller pack cheaper per unit, which is why it's worth checking.
Can I compare grams and ounces?
Yes. Choose the unit of each product; the calculator converts everything to a price per kilogram (1 oz = 28.349523125 g).