Unit Price Calculator
Compare different package sizes, multipacks, and counts on the same measurement basis.
Example values are prefilled. Price is the total paid for all packs.
Best value: Product B.
Currency changes the displayed symbol only. Ranking uses unrounded unit prices. Weight, volume, and count keep separate comparisons until the page is reloaded.
How to compare package prices
Choose weight, volume, or count. Enter each product’s total price, the number of packs that price buys, and the quantity in one pack. Example values are prefilled so the comparison is visible immediately; replace them with your own products.
Choose a common price basis, such as 100 g or 1 litre. The calculator normalizes every compatible product to that basis and marks the lowest unit price as Best value. You can compare two to five products without changing their order.
Different sizes, one measurement basis
For weight, 1 kg is 1,000 g and 1 lb is 16 oz. A 500 g package and a 1 kg package can therefore be compared directly. Ounces here are avoirdupois weight ounces, not fluid ounces or troy ounces.
For volume, 1 L is 1,000 mL. The customary volume units are US liquid units: 1 US gallon is 4 US quarts, 8 US pints, or 128 US fluid ounces. They are not Imperial units. Weight and volume remain separate because converting between them would require the product’s density.
Changing the display from price per 100 g to price per kg changes the displayed numbers but not the ranking. Every product is still compared using the same underlying normalized price.
Multipacks and count-based products
For three 500 g packs sold together for $12, enter $12 as the price, 3 packs, and 500 g per pack. The bundle contains 1,500 g in total, so its unit price is $0.80 per 100 g. Enter the price for the whole bundle, not the price of one individual pack.
Count mode works for products measured as items, pieces, rolls, sheets, servings, loads, or capsules. Choose one shared count label for the comparison. The label does not convert one kind of item into another, so compare products on an equivalent basis and check that sizes, doses, or capacities are genuinely comparable.
What the lowest unit price does not tell you
A larger package is not always cheaper per unit, and the lowest unit price is not automatically the best purchase for every situation. Quality, storage space, expiry dates, usable quantity, and how much you will actually consume can matter more than a small unit-price difference.
Enter the price you would actually pay after any coupon or loyalty discount you want included. Treat taxes, delivery charges, or other fees consistently across the products if they matter to the comparison. The calculator does not look up offers or estimate waste.
Currency is a display label only. All entered prices must already use the same currency; changing the symbol does not perform currency conversion. The comparison runs in the browser and is not saved to localStorage or encoded in the page URL.
Unit price formulas
Weight comparisons use grams as the common base, volume comparisons use millilitres, and count comparisons use the selected count basis. C is the conversion factor from the entered unit to that common base.
Examples
500 g versus 1 kg
1Input
Product A: $4 for 1 × 500 g. Product B: $7 for 1 × 1 kg.
Show result
Result
A: $0.80 per 100 g. B: $0.70 per 100 g. B is best value.
A costs approximately 14.29% more per 100 g than B.
Multipack versus a single pack
2Input
Product A: $12 for 3 × 500 g. Product B: $9 for 1 × 1 kg.
Show result
Result
A: 1,500 g total, $0.80 per 100 g. B: $0.90 per 100 g. A is best value.
B costs 12.5% more per 100 g than A.
500 mL versus 1 litre
3Input
Product A: $2.50 for 500 mL. Product B: $4 for 1 L.
Show result
Result
A: $0.50 per 100 mL. B: $0.40 per 100 mL. B is best value.
A costs 25% more per 100 mL than B.
12 items versus 20 items
4Input
Product A: $8 for 12 items. Product B: $11 for 20 items.
Show result
Result
A: approximately $0.667 per item. B: $0.55 per item. B is best value.
A costs approximately 21.21% more per item than B.
Frequently Asked Questions
Can I compare grams with ounces or millilitres with US fluid ounces?
Yes. Weight mode converts g, kg, oz, and lb to a common weight basis. Volume mode does the same for mL, L, US fluid ounces, US pints, US quarts, and US gallons. Weight, volume, and count cannot be mixed within one comparison.
Is the price for one pack or the whole multipack?
Enter the total price for all packs listed in that row. If a bundle of three 500 g packs costs $12, enter price 12, packs 3, and size per pack 500 g.
Why can two displayed prices look equal but both be marked Best value?
The calculator compares unrounded values and treats extremely small floating-point differences as equal. Displayed prices are rounded separately so insignificant numeric noise does not create a false winner.
What happens if a product is free?
A zero price is valid when the pack count and quantity are valid. Free products tie for best value. Other products do not receive a percentage premium because a percentage comparison against a zero best price would require division by zero.
Does changing the currency convert the prices?
No. Currency changes only the displayed symbol. Enter every product price in the same currency before comparing them.
Are my product names and prices saved?
No. The calculator keeps the current comparison in page memory only. It does not save the inputs in localStorage or put them in the URL, so reloading or leaving the page clears them.