Cost per Use & Value
Old Size vs New Size Calculator
Calculate old size vs new size using the quantity or usage that actually matters.
Enter your numbers
Enter your values to calculate
Your result will appear here without loading a separate page.
What this calculator tells you
The calculator turns the shopping terms you enter into a comparable cost or value figure. The result is based only on the values you provide, so you can rerun it with a different store, package, shipping charge or promotion.
How to use the result
Use the highlighted result as the comparison number, then check the tradeoffs around it. A lower unit price can still be a poor decision if you will waste the extra quantity, a subscription can cost more if you over-order, and cashback is not the same as a lower checkout total.
What to verify before buying
- Package quantity and unit of measure match the label or product page.
- Coupons and promotions apply to the exact item and quantity.
- Shipping, taxes, fees and membership requirements are included where relevant.
- Return or warranty terms are checked directly with the retailer when they matter.
Sources and verification
These sources support the consumer-shopping principles discussed on this page. Your own retailer's current offer and policy still control the actual transaction.
NIST SP 1181 — Unit Pricing Guide, 2025 EditionNational Institute of Standards and Technology · verified 2026-08-09Official U.S. best-practice guide for unit pricing; updated May 20, 2026.Uniform Unit Pricing: Tools for Consumers to Fight ShrinkflationNational Institute of Standards and Technology · verified 2026-08-09Official consumer explanation of unit pricing and shrinkflation.