Price Elasticity of Demand Calculator
Estimate how sensitive demand is to a price change. Enter starting and ending values, choose a method, then click Calculate.
Tip: The midpoint method is usually preferred because it gives consistent results whether price rises or falls.
What is price elasticity of demand?
Price elasticity of demand (PED) measures how much quantity demanded changes when price changes. It helps you understand whether buyers are highly sensitive to price (elastic demand) or not very sensitive (inelastic demand).
In plain language: if a small price increase causes a big drop in quantity demanded, demand is elastic. If quantity barely moves when price changes, demand is inelastic.
Formula used in this calculator
1) Midpoint (Arc Elasticity)
PED = (% change in quantity demanded) / (% change in price), where:
- % change in quantity = (Q2 - Q1) / ((Q1 + Q2) / 2)
- % change in price = (P2 - P1) / ((P1 + P2) / 2)
This approach reduces bias and is generally better for comparing before/after values.
2) Initial-value percentage method
This method uses initial values as denominators:
- % change in quantity = (Q2 - Q1) / Q1
- % change in price = (P2 - P1) / P1
It is simple and often taught early, but it can produce different values depending on direction of change.
How to interpret the result
- |PED| > 1: Elastic demand (buyers are price sensitive)
- |PED| < 1: Inelastic demand (buyers are less price sensitive)
- |PED| ≈ 1: Unit elastic demand
The absolute value tells you sensitivity strength. The sign tells direction. A negative PED is typical for most normal goods (price up, quantity down). A positive PED is unusual and may occur in special cases.
Why this matters for pricing decisions
Revenue strategy
Elasticity gives a shortcut for estimating revenue effects:
- If demand is elastic, raising price usually reduces total revenue.
- If demand is inelastic, raising price usually increases total revenue.
- If demand is unit elastic, revenue is roughly unchanged by small price moves.
Marketing and promotion planning
A business with elastic demand may benefit more from discounts, promotions, and value bundles. A business with inelastic demand may focus more on brand strength, convenience, and product differentiation than price cuts.
Worked example
Suppose price rises from $10 to $12 and quantity demanded falls from 1,000 to 850.
- Midpoint %ΔQ = (850 - 1000) / 925 = -16.22%
- Midpoint %ΔP = (12 - 10) / 11 = +18.18%
- PED = -16.22% / 18.18% = -0.89
Absolute elasticity is 0.89, so demand is inelastic. In this case, the price increase would typically raise total revenue.
Common factors that influence elasticity
- Availability of substitutes: More substitutes usually means more elastic demand.
- Necessity vs. luxury: Necessities are often more inelastic than luxuries.
- Share of income: Expensive items take a bigger budget share and tend to be more elastic.
- Time horizon: Demand often becomes more elastic over longer periods.
- Brand loyalty: Strong loyalty can reduce price sensitivity.
FAQ
Should PED always be negative?
For most products, yes. A positive PED can happen in unusual market situations, but the standard demand relationship is negative.
Which method should I use?
Use midpoint (arc elasticity) for most practical before/after analysis. It is more stable and widely recommended.
Can I use this for large price changes?
Yes, but remember PED is still a simplified summary. For major strategic changes, combine elasticity with market segmentation, competitor response, and cost analysis.