Irish Calculators
Business

Unit Price and Package Value Comparison Calculator

Convert package prices to a common unit within the same quantity dimension. Enter actual promotional totals; the calculator does not infer offers or calculate full industrial production costs.

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Your numbers

Each row: package price,package quantity,unit. Units: g,kg,ml,l,cm,m,each. Use the total quantity and actual payable price after any offer; no headers.
Your figures stay on this device.

How the calculation works

Compare package offers using a common unit price. The tool converts compatible sizes before dividing price by quantity, so a lower shelf price is not automatically mistaken for better value.

Unit price = package price / quantity in a common base unit. Kilograms, litres, metres and items are compared only within their own dimension.

  1. Describe the complete offer

    Use the amount paid for the full package and the quantity obtained for that amount. If a promotion changes either figure, enter the resulting price and quantity rather than expecting the form to interpret the promotion.

  2. Convert to a shared unit

    Compatible mass, volume or length quantities are normalised before comparison. An item count remains a count; the calculator cannot infer a product's mass or volume from the word each.

  3. Compare normalised prices

    Divide package price by its converted quantity. Compare unit costs rather than package prices. The percentage saving compares the lowest unit price with the first listed offer, which is not necessarily the most expensive offer.

Worked example: Different mass units

Sample inputs demonstrate the method. They are not a forecast or product offer.

The example compares €3 for 500 g with €5 for 1 kg. These are €6 and €5 per kilogram. The second offer costs more at checkout but is about 16.67% cheaper per kilogram, using €6 as the comparison base.

Prices and package quantities
3,500,g 5,1,kg

Expected result

Lowest price per kg
€5.00
Saving versus first offer
16.67%
Worked example: Different volume units

Sample inputs demonstrate the method. They are not a forecast or product offer.

Prices and package quantities
2,500,ml 3,1,l

Expected result

Lowest price per litre
€3.00
Saving versus first offer
25%

Understanding your result

Unit price measures the cost of an equal quantity. It does not establish product quality, suitability or whether a larger package will be used before it spoils.

The cheapest unit price may require more cash upfront. Review package cost and required quantity separately when deciding whether an offer suits the purchase you actually need.

Questions you might have

How should I enter a buy-two offer?

Enter the total payable price and total quantity for the two packages. This keeps the promotion’s conditions explicit instead of assuming that every package qualifies.

Choosing the right inputs

Prices and package quantities
Enter one row as package price,quantity,unit, without headings or thousands separators. Supported units are g, kg, ml, l, cm, m and each. Keep all offers in one compatible dimension, such as mass or volume, and use the actual total quantity included in the stated price.

Common mistakes to avoid

  • Do not compare kilograms with litres unless you first supply a justified conversion outside this tool; they measure different dimensions.
  • Do not enter the quantity of one pack with the total price of a multi-pack, or the reverse.

Assumptions to check

  • Use amounts in one currency and one reporting period. Results are labelled EUR; the arithmetic also works for another consistent currency.
  • Quantity must be positive. Promotions are represented by their actual total price and total quantity, not inferred from advertising text.

Sources and method

Read our calculation and testing approach.