Unit Price Calculator
Rank up to eight offers by price per weight, volume or item with multipack and coupon support.
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Rank multipack and coupon offers on a common price per weight, volume or item.
How to use it
- 1Choose weight, volume or item count and a comparison unit.
- 2Enter each offer’s full price, one-pack size and pack count.
- 3Apply any coupon for the entire offer, then compare.
- 4Review the lowest unit price and download CSV or JSON.
Example
- Input
- 4.50 for 500 g vs 8.40 for two 0.5 kg packs with a 0.40 coupon
- Output
- Offer B is lower at 0.80 per 100 g versus 0.90 for Offer A.
What happens to your data
Offer prices, quantities and coupon amounts stay in this tab. Anonymous workflow records exclude those values.
Last updated November 2026
Compare pack sizes, multipacks and coupon offers on one common basis. This price per unit calculator ranks two to eight offers by cost per weight, volume or item count. It handles mixed compatible units, such as grams and pounds, and keeps US fluid ounces separate from Imperial fluid ounces. Download the ranked results as CSV or JSON.
How it works
Start with the total offer price and subtract the coupon for the entire offer. Multiply the quantity per pack by its pack count, then convert the total into one base unit: grams, millilitres or items. Divide the net price by the total quantity and multiply by the chosen comparison size, such as 100 g. For example, when you compare price per ounce by weight, do not enter a fluid-ounce volume. The grocery unit price calculator separates weight, volume and item count so a comparison uses compatible quantities.
Fixed unit conversion factors and entered amounts are represented as integers with decimal scales. Ranking and ties compare exact ratios before display rounding. The displayed price and percentage are rounded for readability; exports preserve the exact unit-price numerator and denominator. A zero-cost offer can rank first, and any percentage above a zero unit price is undefined.
Use 2–8 offers, 1–9,999 packs per offer and positive quantities. Sizes allow up to seven digits before and four after the decimal point for weight or volume. Item counts are whole numbers. Price and coupon have up to seven digits before and two after the point, and a coupon cannot exceed the total price. Use one currency and enter the total as you expect to pay it, including any applicable charges or discounts that are part of the comparison.
Worked example: Compare a single pack and a multipack
- Input
- Offer A: 4.50 for 500 g. Offer B: 8.40 for two 0.5 kg packs, with a 0.40 coupon.
- Result
- Offer B is 0.80 per 100 g. Offer A is 0.90 per 100 g, or 12.5% above the lowest unit price.
The offer with the lower unit price can require spending more in total.
Common use cases
- Compare a small grocery pack with a discounted multipack.
- Check price per 100 g across labels using grams, kilograms, ounces or pounds.
- Compare bottle refills labelled in litres and US or Imperial fluid ounces.
- Rank different item-count offers and export the comparison.
Frequently asked questions
Do I enter the price of one pack or the full multipack?＋
Enter the full price for the offer. Enter the size of one pack separately, then set the number of packs included in that price.
Can I compare ounces and millilitres?＋
Yes for fluid ounces. Choose volume and select US fl oz or Imperial fl oz as printed on the offer. An ounce of weight is a mass unit and cannot be compared with millilitres.
How are ties and free offers handled?＋
Offers are tied only if their unrounded unit-price ratios are equal. A coupon that fully covers the price makes the offer free. A percentage increase over a zero price is unavailable.
Does the lowest unit price mean the lowest total price?＋
It means the lowest cost per comparison unit. The full amount paid and the quantity you need can still differ between offers.
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