How do I compare unit prices between two products?

Divide each product's total price by its quantity. The result is the cost per unit. The product with the lower cost per unit is the better deal. For example: a 500g bag for $4.00 costs $0.008 per gram, while a 750g bag for $5.50 costs $0.0073 per gram — making the larger bag cheaper per gram.

Is buying in bulk always cheaper?

Not always. Bulk items often have a lower unit price, but you should also consider whether you will use the full amount before it expires, storage space, and upfront cost. This calculator shows you the exact unit cost so you can make an informed decision based on your own situation.

What does cost per unit mean?

Cost per unit is how much you pay for a single measurable amount of a product — such as one gram, one ounce, one milliliter, one count, or one serving. It lets you fairly compare products sold in different package sizes by putting them on the same scale.

Can I compare products with different units?

You should compare products using the same unit type. For weight, use all grams or all ounces. For liquid, use all milliliters or all fluid ounces. If two products use different units (like one in grams and one in ounces), convert them first. 1 ounce equals 28.35 grams, and 1 fluid ounce equals 29.57 milliliters.

Why do store price tags sometimes show unit prices?

Many stores are legally required to display unit pricing on shelf labels so shoppers can compare products fairly. However, the unit shown varies between stores (some use per 100g, others per oz), which can make it hard to compare across different stores. This calculator lets you enter any quantity and unit for an instant side-by-side comparison.

Price Comparison Calculator – Compare Unit Prices and Find the Best Deal on Any Product

Price Comparison Calculator

Enter the price and quantity of each product to instantly see the cost per unit side by side. Find out which size or brand gives you the most for your money — free and works on any device.

No data stored

Instant results

Mobile friendly

100% free

Up to 6 products

Enter Products to Compare

Quantity Unit

Currency Symbol

Sales Tax Rate (%)

Applied equally to all products

How many units do you need?

See total cost for your needed amount

Discount / Coupon (%)

Applied to all products before comparison

Comparison Results

Best Value

—

— per unit

All Products — Cost Per Unit

Quick Formula

Cost per unit = Total price ÷ Quantity
Savings vs. worst deal = (Worst unit cost − Best unit cost) × Your quantity needed
Tax and discount are applied to price before dividing.

Enter at least 2 products above and click Compare Prices to see which gives you the best deal.

Cost Per Unit — Visual Comparison

Price Share of Each Product

How to Use This Calculator

Enter the name, total price, and quantity of each product. The calculator divides price by quantity to find the cost per unit for each one. The product with the lowest cost per unit is highlighted as the best deal.

Use the same unit type for all products so the comparison is fair
Click Add Another Product to compare up to 6 items at once
Turn on Advanced Options to add a sales tax rate, a coupon discount, or the quantity you actually need — so you can see total spend side by side
Product names are optional, but they make results easier to read
Results update every time you click Compare Prices

Tip: store shelf labels often show different base units (per 100g vs per oz). This tool lets you enter the actual pack size for a truly equal comparison.

Common Unit Conversion Reference

From	To	Multiply by
1 oz	grams	28.35
1 lb	grams	453.59
1 kg	grams	1,000
1 fl oz	ml	29.574
1 liter	ml	1,000
1 gallon	fl oz	128
1 pint	fl oz	16
1 yard	feet	3
1 meter	cm	100

Always use the same unit for all products. Convert first if packages show mixed units.

When Bigger Is Not Always Better

A larger pack often costs less per unit, but not always. Before buying in bulk, consider these points:

Expiry date — perishable items may go bad before you finish them
Storage space — large packs need more room at home
Cash flow — a higher upfront price ties up more money even if it saves in the long run
Quality differences — store brands may have a lower unit price but a different formula than name brands
Sale pricing — a smaller pack on sale can sometimes beat the regular bulk price
Loyalty programs — some stores offer extra discounts on certain sizes through membership cards

Use the quantity you need field in Advanced Options to see your real total cost for each option.

Unit Pricing Laws Around the World

Many countries require stores to show the unit price on shelf labels, but the rules differ:

Country / Region	Unit Pricing Rules
🇺🇸 United States	Required in most states for food items. Rules vary by state.
🇪🇺 European Union	Mandatory for most pre-packaged food and household goods.
🇬🇧 United Kingdom	Required for food, drink, and some non-food items under the Price Marking Order.
🇦🇺 Australia	Required for most grocery items under Consumer Law.
🇨🇦 Canada	Not federally mandated; some provinces have rules.
🇮🇳 India	MRP (Maximum Retail Price) labeling required; unit pricing less common.

Even where unit prices are shown, they may use different base units across stores, making this calculator handy for cross-store comparisons.

Frequently Asked Questions

It divides each product's total price by its quantity to get the cost per unit. For example, a 400g jar for $3.20 costs $0.008 per gram. A 600g jar for $4.50 costs $0.0075 per gram. The second jar is cheaper per gram even though it costs more in total. The calculator does this math for all your products and highlights the winner.

You need to convert to a common unit first. One ounce equals 28.35 grams. So a 16 oz product is 453.6 grams. Enter all quantities in the same unit — either all grams or all ounces — to get a fair comparison. The conversion table on this page can help you do that quickly.

Yes. Just enter the price and pack size from each store as separate products. For example, add "Store A – 500g bag at $4.99" and "Store B – 750g bag at $6.99" and the calculator will tell you which is cheaper per gram. You can also use the product name field to label each one clearly.

Click Advanced Options below the product rows and enter the discount percentage. The calculator will subtract the discount from each product's price before computing the unit cost. If only one product has a coupon, you can apply the discount just to that product's price before entering it.

Not always. The lowest unit price is the best math answer, but your real-life decision should also weigh expiry dates (especially for food), storage space, how much you actually use, and your current budget. The calculator gives you the data — the final call is yours.

Yes. You can compare any price-per-quantity situation: streaming plans by cost per month, phone plans by cost per GB of data, gym memberships by cost per visit, or cleaning services by cost per square foot. Just enter the total price and the relevant quantity for each option.

Cost Per 100g by Total Price & Pack Size

How much you pay per 100 grams at different price and pack size combinations. Lower is better.

Pack Size	$1.00	$2.00	$3.00	$4.00	$5.00	$6.00

Formula: (Price ÷ Pack size in grams) × 100. Highlighted cells show the best deals at each price point.

Typical Supermarket Pack Size Ladder

Common product pack sizes and how unit cost usually scales across sizes. Values are illustrative examples.

Pack Size	Typical Price	Per 100g Cost	vs. Smallest	vs. Largest

Example based on a typical dry grocery product. Actual prices vary widely by category, brand, and retailer.

Monthly & Annual Cost by Unit Price

How much you spend per month and per year at different unit costs, assuming various daily usage amounts.

Unit Cost ($/unit)	10/day	25/day	50/day	100/day	200/day	Annual (100/day)

Monthly = unit cost × daily usage × 30. Annual = unit cost × 100 units/day × 365. Useful for coffee, protein powder, dog food, or any regularly consumed product.

Typical Unit Price Benchmarks by Product Category

Reference ranges for common products. Use these to judge if a price you see is average, cheap, or expensive.

Product Category	Common Unit	Budget Range	Mid Range	Premium Range
Chicken breast (fresh)	per 100g	$0.30–$0.55	$0.55–$0.85	$0.85–$1.50+
Whole milk	per 100ml	$0.06–$0.10	$0.10–$0.16	$0.16–$0.30+
Pasta (dry)	per 100g	$0.08–$0.14	$0.14–$0.25	$0.25–$0.70+
Ground coffee	per 100g	$0.60–$1.20	$1.20–$2.50	$2.50–$6.00+
Dish soap	per 100ml	$0.10–$0.20	$0.20–$0.35	$0.35–$0.60+
Toilet paper	per sheet	$0.01–$0.02	$0.02–$0.04	$0.04–$0.08+
Paper towels	per sheet	$0.01–$0.03	$0.03–$0.06	$0.06–$0.12+
Laundry detergent	per wash	$0.08–$0.15	$0.15–$0.30	$0.30–$0.55+
Vitamin C (tablets)	per tablet	$0.04–$0.08	$0.08–$0.18	$0.18–$0.50+
Bottled water	per 100ml	$0.01–$0.03	$0.03–$0.06	$0.06–$0.15+
Protein powder	per serving	$0.50–$1.00	$1.00–$2.00	$2.00–$4.00+
Cat / dog food (dry)	per 100g	$0.15–$0.30	$0.30–$0.60	$0.60–$1.50+

Ranges are approximate US market references and will vary by country, year, store format, and brand tier. Use as a rough guide only.

How a Discount Changes the Effective Unit Price

Starting unit prices after applying common coupon and sale discount percentages.

Original Unit Price	5% off	10% off	15% off	20% off	25% off	30% off	50% off

Effective unit price = original unit price × (1 − discount%). Use the Advanced Options section in the calculator above to apply a discount automatically.