Beyond Groceries

Unit pricing is one case of a wider habit: putting two unlike things onto a shared scale so you can compare them. A car rated "30 mpg" and one rated "8 L/100 km" seem incomparable until you convert to a common unit.

The same move works everywhere:

• Cost per kilowatt-hour compares energy plans
• Dollars per square foot compares apartments
• Calories per gram compares foods by density

Whenever two options differ in more than one way, reduce both to a per-unit rate. It turns a messy choice into a single number.