Calculate& Decide

Everyday Math calculator

Unit Price Comparison Calculator

This calculator divides each package price by its quantity so differently sized options can be compared fairly.

Updated · Inputs stay in your browser

Enter your values

Choose the symbol used to display amounts.
Optional short name.
Package price.
Quantity in a common unit.
Optional short name.
Package price.
Use the same unit as Option A.

Your values stay on this device. Nothing is sent to Calculate & Decide unless you deliberately use your device's share feature.

What this result means

This calculator divides each package price by its quantity so differently sized options can be compared fairly. The results panel explains the main number and the quantities that produced it, so you can check whether the estimate answers your real question.

Formula used

Unit price = Package price ÷ Package quantity.

Step-by-step calculation

  1. Validate every required value and reject values outside the stated field limits.
  2. Convert rates and time periods to the units required by the formula.
  3. Calculate with full JavaScript number precision; do not round intermediate values.
  4. Round only the displayed result and explain the practical meaning.

Worked example

A 750 g package at $6 costs $0.008 per gram. A 1,000 g package at $7.50 costs $0.0075 per gram, about 6.25% less per gram.

Assumptions and limitations

  • Both quantities use the same unit.
  • The full quantity is usable and comparable in quality.
  • Coupons, membership costs, waste, and storage costs are excluded.

How to use this calculator

  1. Choose a currency symbol when the tool uses money.
  2. Enter values in the units shown beside each field.
  3. Select Calculate, then read both the main result and interpretation.
  4. Change one uncertain input at a time to understand sensitivity.
  5. Use Copy result or Share only when you choose to move the result outside this page.

Common mistakes

  • Comparing package prices without matching quantities.
  • Entering grams for one option and kilograms for the other.
  • Choosing the larger package despite likely waste.

Frequently asked questions

Can I compare litres, kilograms, or counts?

Yes, as long as both quantities use the same unit.

Does the cheaper unit price always win?

No. Quality, spoilage, storage, and cash budget may matter.

Why show four decimals?

Small per-unit prices often need extra precision to reveal a difference.

Methodology and sources

Formula definitions and edge-case behavior are documented on our Methodology page. No external data is fetched by this calculator.

See the site-wide calculation methodology and editorial standards. Formula errors can be reported through the error-reporting instructions.

Published and reviewed .