Why the midpoint method matters
The midpoint method is used when economists compare two points on a demand, supply, income, or related price schedule. It avoids a common problem. A simple percentage change gives different answers when you move forward or backward between the same two values. The midpoint method fixes this by using the average of the old and new values as the base.
This calculator helps you measure arc elasticity. It is useful when data comes from market surveys, classroom tables, price tests, or business experiments. You can study how quantity changes when price changes. You can also test income elasticity and cross price elasticity.
What the result means
The elasticity coefficient shows sensitivity. A value above one means the response is elastic. Quantity moves by a larger percentage than the driver. A value below one means the response is inelastic. Quantity moves by a smaller percentage. A value near one is unit elastic.
For demand, the raw coefficient is often negative. That happens because price and quantity usually move in opposite directions. Many textbooks classify demand by the absolute value. This tool shows both the raw value and the value used for classification.
Revenue insight
Price elasticity helps explain total revenue. When demand is elastic, a price increase can reduce revenue. A price cut can raise revenue. When demand is inelastic, a price increase can raise revenue. A price cut can reduce revenue. The calculator compares starting revenue and ending revenue when price data is entered.
Good data habits
Use matching units for both points. Do not mix monthly quantity with weekly quantity. Use the same currency for both driver values. Avoid zero or negative averages, because percentage changes become invalid. Check whether the values describe the same market, product, time period, and customer group.
Practical uses
Students can verify homework steps. Teachers can create examples quickly. Analysts can test price changes before a campaign. Small businesses can compare old and new sales results. The midpoint method does not prove causation by itself. It gives a clean measure of movement between two observed points. Pair the coefficient with charts, customer notes, and market context. This keeps conclusions balanced, useful, and easier to explain during careful pricing reviews.