Bigger packs are usually cheaper per unit, but not always, as promotions on small sizes often beat bulk packs. Comparing the unit price is the only reliable way to know.
How to use the Price / Quantity Calculator
- Smaller product: quantity
- Smaller product: price
- Larger product: quantity
- Larger product: price
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter the quantity and price of the smaller and the larger product.
Inputs explained
| Field | What to enter |
|---|---|
| Smaller product: quantity | A number |
| Smaller product: price | Amount in your currency |
| Larger product: quantity | A number |
| Larger product: price | Amount in your currency |
What each result means
- Smaller product: price per unit = [Smaller product: price]÷[Smaller product: quantity]
- Larger product: price per unit = [Larger product: price]÷[Larger product: quantity]
- The larger quantity would have cost at the smaller product’s price = [Smaller product: price per unit]×[Larger product: quantity]
- You save buying the larger product = [Smaller product: price per unit]×[Larger product: quantity] – [Larger product: price]
- Saving per unit = (1 – [Larger product: price per unit]÷[Smaller product: price per unit])×100
Formula
Price per unit = price ÷ quantity
Saving = (higher unit price − lower unit price) × quantity bought
Worked example
Inputs: Smaller product – quantity: 500; Smaller product – price: $3.49; Larger product – quantity: 1,200; Larger product – price: $7.99.
Results: Smaller product – price per unit = $0.00698; Larger product – price per unit = $0.00666; Better deal = Larger product; The larger quantity would have cost at the smaller product's price = $8.38; You save buying the larger product = $0.39; Saving per unit = 4.61 %.
Frequently asked questions
Is bigger always cheaper?
No. Check the unit price, especially when smaller sizes are on sale.
How do I compare different units?
Convert both to the same unit (e.g. grams or ounces) first.
Should I always buy the cheaper unit price?
Only if you will use it all before it spoils.