To calculate unit price, divide the total package price by the quantity inside the package. The answer is the cost of one item, kilogram, litre, ounce, serving, sheet, tablet, or another standard unit. When comparing two products, convert both quantities to the same unit before deciding which package is cheaper.
Compare two products by price, package quantity, measurement unit, unit-cost difference, and percentage savings.
The result shows how much one standard unit costs.
What Is Unit Price?
Unit price is the cost of one standard measurement unit. It lets you compare products that have different package prices or package sizes.
A unit may be one item, one kilogram, one litre, one ounce, one pound, one serving, one sheet, or another quantity that makes sense for the product.
The Unit Price Calculator can compare two products and convert compatible weight and volume units automatically.
The Unit Price Formula
The basic unit-price formula is total price divided by total quantity.
The price must represent the amount you will actually pay. The quantity must represent the full usable amount inside the package.
When the package contains six items and costs $12, the cost of one item is $2.
Worked Example: Price per Item
Suppose a carton contains 12 items and costs $8.40.
Divide $8.40 by 12. The answer is $0.70 per item.
This unit price can now be compared with another carton, even when the other package contains a different number of items.
How to Calculate Price per Kilogram
When a product is sold by weight, first determine whether the quantity is already in kilograms.
For a 500-gram package costing $4.50, convert 500 grams to 0.5 kilograms. Divide $4.50 by 0.5 to get $9 per kilogram.
You can also divide the price by grams first and multiply the result by 1,000.
How to Calculate Price per Litre
For liquid products, compare prices using litres or millilitres.
A 750-millilitre bottle contains 0.75 litres. When it costs $3.60, dividing $3.60 by 0.75 gives $4.80 per litre.
A one-litre bottle costing $4.40 would therefore have the lower unit price.
How to Calculate Price per Ounce or Pound
Use ounces or pounds consistently when comparing products labelled with imperial weight units.
Sixteen ounces equal one pound. An eight-ounce package costing $3 has a unit price of $0.375 per ounce or $6 per pound.
The calculator can normalise ounces and pounds into a common price-per-pound comparison.
Use the Final Price After Discounts
When a coupon or instant discount applies, calculate unit price using the reduced amount you will actually pay.
For example, a ten-item package normally costing $10 has a unit price of $1 per item. After a $2 coupon, its unit price becomes $0.80 per item.
Do not include a coupon that cannot be used for your purchase or that requires buying additional products.
Use the Correct Quantity
The package quantity should reflect the amount you can actually use.
Check whether the label gives net weight, drained weight, serving count, sheet count, tablet count, or another measurement.
When part of the package is packaging material, liquid that will be discarded, or another unusable portion, a different usable-quantity comparison may be more meaningful.
Unit Price for Multipacks
For a multipack, divide the total pack price by the total number of individual items.
If a box contains four inner packs with six items in each, the total quantity is 24 items.
Divide the complete box price by 24 rather than dividing by four inner packs unless the inner pack is the unit you need.
Common Unit-Price Mistakes
A common mistake is comparing package prices without considering quantity. A cheaper package may still cost more per unit.
Another mistake is comparing grams with kilograms or millilitres with litres without converting them first.
It is also easy to use the regular price when a valid discount changes the amount actually paid.
When Unit Price Is Most Useful
Unit price is useful for groceries, household products, toiletries, medicines, office supplies, cleaning products, and bulk purchases.
It helps when two packages contain the same type of product but differ in size, count, or price.
Unit price does not measure quality, freshness, convenience, or the likelihood that part of a large package will be wasted.
Conclusion
Calculate unit price by dividing the total price by the package quantity.
Convert products to the same measurement unit before comparing them, and use the final price you will actually pay.
Use the Unit Price Calculator to compare two packages and see the lower normalised cost.
FAQs
How do I calculate unit price?
Divide the total package price by the total quantity in the package.
How do I calculate price per item?
Divide the package price by the number of individual items.
Can I compare grams with kilograms?
Yes. Convert both quantities to grams or kilograms before comparing their unit prices.
Should I use the sale price?
Yes. Use the final price you will actually pay when the discount applies.
Does the lowest unit price always mean the best purchase?
No. Quality, waste, storage, expiry, and immediate cost can also affect the decision.