Price Elasticity Calculator
Compute the price elasticity of demand — the percentage change in quantity demanded divided by the percentage change in price. Tells you whether buyers are sensitive to price changes (elastic) or stick with their purchases regardless (inelastic).
Last updated: May 2026
Compare with similar
About this calculator
Price elasticity of demand (PED) measures how responsive quantity demanded is to a change in price. The formula here is PED = (%ΔQ) / (%ΔP), with percentage changes computed against the initial values: %ΔQ = (Q₁ − Q₀) / Q₀ and %ΔP = (P₁ − P₀) / P₀. The result is a dimensionless number, typically negative because raising price usually reduces quantity (demand curves slope down). Convention varies: economists often report the absolute value |PED| to focus on magnitude. Categorisation: |PED| > 1 is elastic (a 1% price increase causes more than a 1% drop in quantity — total revenue falls); |PED| < 1 is inelastic (revenue rises when price rises); |PED| = 1 is unit elastic (revenue is unchanged). Goods that are necessities, addictive, or have no close substitutes (gasoline, insulin, salt, electricity) tend to be inelastic; goods with many substitutes, that are luxuries, or that represent a large fraction of income (restaurant meals, branded clothing, holidays) tend to be elastic. Variables: initialPrice and newPrice must both be > 0; initialQuantity > 0; newQuantity ≥ 0. Edge cases: %ΔP = 0 (price did not change) makes elasticity undefined and the calculator returns 0; the formula uses the simple percentage-change method (not the midpoint or arc method), which can give asymmetric results depending on which point you treat as "initial". The midpoint formula avg = (Q₀ + Q₁)/2 in the denominators eliminates this asymmetry; many textbooks prefer it for that reason. The point elasticity (dQ/dP · P/Q) is the limit as ΔP → 0 and is more useful when you have a continuous demand function. Elasticity also varies along a single demand curve — it is not a single number for a product, but a property of a specific point or interval.
How to use
Example 1 — Price hike on a product. A retailer raises a price from $10 to $12, and weekly sales drop from 1,000 units to 800. Enter Initial Price = 10, New Price = 12, Initial Quantity = 1000, New Quantity = 800. %ΔP = (12 − 10) / 10 = 0.20 = 20%; %ΔQ = (800 − 1000) / 1000 = -0.20 = -20%. PED = -0.20 / 0.20 = -1.0 (unit elastic). ✓ Revenue stayed the same: 1000·10 = 10,000 before, 800·12 = 9,600 after — close to the predicted no-change result, with small rounding. At unit elasticity, raising or lowering price barely moves revenue; the demand curve is on the boundary between elastic and inelastic. Example 2 — Inelastic good (gasoline). Gas price rises from $3.50 to $4.00 and weekly demand falls slightly from 50,000 gallons to 49,000. Enter 3.50, 4.00, 50000, 49000. %ΔP = 0.50/3.50 ≈ 14.29%; %ΔQ = -1000/50000 = -2%. PED ≈ -2 / 14.29 ≈ -0.14 (highly inelastic). ✓ A 14% price increase only reduced quantity by 2%, so revenue rose substantially (49000·4 = 196,000 vs 50000·3.50 = 175,000). This is exactly why gas stations and utility companies have pricing power — demand barely responds to price within normal ranges.
Frequently asked questions
What's the difference between elastic and inelastic demand?
Elastic demand (|PED| > 1) means buyers are sensitive to price — a small price change produces a proportionally larger quantity change. Lowering price increases revenue (because the quantity gain more than offsets the per-unit revenue loss); raising price decreases revenue. Examples: restaurant meals, branded clothing, luxury cars, holidays — substitutes are plentiful and consumers can defer or skip purchases. Inelastic demand (|PED| < 1) means buyers are insensitive — quantity changes proportionally less than price. Raising price increases revenue; lowering it decreases revenue. Examples: gasoline, prescription drugs, basic groceries, utilities — substitutes are limited and the goods are necessary. Unit elasticity (|PED| = 1) is the boundary: revenue stays the same regardless of price changes. Knowing your product's elasticity is essential for pricing decisions, sales-promotion design, and forecasting how regulations (taxes, subsidies) will affect markets.
How does elasticity affect pricing strategy?
For elastic demand, lower prices grow revenue (more units sold more than compensate for the lower per-unit price); raising prices hurts revenue. Discounting strategies, loss leaders, penetration pricing, and high-volume low-margin business models work well in elastic markets. For inelastic demand, the opposite: raising prices grows revenue (small loss in quantity, big gain in per-unit price); discounting destroys revenue. Premium pricing, captive-audience pricing (movie-theatre concessions, airport restaurants), and monopolistic pricing all rely on inelastic demand. Elasticity also varies along the demand curve — typically more elastic at high prices and more inelastic at low prices — so the "right" price strategy depends on where you sit on the curve. Always test small price changes before making big ones; real elasticity can differ substantially from textbook estimates.
What factors make demand more elastic or inelastic?
Demand is more elastic when: (1) good substitutes exist (Coke vs Pepsi, brands of pasta); (2) the good is a luxury rather than a necessity; (3) it represents a large fraction of income (a $50,000 car is more elastic than a $5 sandwich); (4) consumers have time to adjust (long-run elasticity is almost always larger than short-run — gasoline demand is inelastic over months but elastic over decades as buyers switch to more efficient vehicles); (5) the market is broadly defined ("food" is inelastic, "Granny Smith apples" is elastic). Demand is more inelastic when: (1) the good is necessary (insulin, electricity); (2) there are no close substitutes; (3) it is addictive (cigarettes, alcohol); (4) it is a small portion of the budget (salt, ketchup); (5) consumers have limited time to adjust. Always specify the time horizon when discussing elasticity.
What are the most common mistakes people make computing elasticity?
The first is reporting elasticity with the wrong sign — PED is typically negative for normal goods because price and quantity move in opposite directions; reporting a positive number suggests a Giffen or Veblen good (very rare) or an arithmetic error. The second is using the simple percentage-change formula and getting different elasticities depending on which point you call "initial" — the midpoint (arc) elasticity formula avoids this asymmetry. The third is generalising elasticity from a single data point as if it applies across the entire demand curve; elasticity varies along the curve and across time. The fourth is confusing elasticity with the slope of the demand curve — they are related but different; two demand curves can have the same elasticity at one point but very different slopes. The fifth is forgetting that elasticity assumes "all else equal" — if a price change coincides with a marketing campaign, weather change, or competitor action, the observed quantity change includes those effects too.
When should I not use this calculator?
Skip it when the price change is large (more than ~25%); the simple percentage-change formula is unreliable across big jumps because it implicitly assumes a constant elasticity, which rarely holds. Use the arc/midpoint elasticity formula or a fitted demand curve for big changes. Do not use it for cross-price elasticity (effect of one product's price on another's demand) or income elasticity — those have their own formulas and require different inputs. It is the wrong tool when supply or other demand-shifters change at the same time as price; you cannot infer pure price elasticity from observational data unless you control for those factors. Avoid it for very inelastic goods near zero quantity (insulin, water) where the formula's linearity assumption breaks down at the edges. Finally, do not use it for monopolistic-competition pricing optimisation without combining with cost data — knowing PED tells you how revenue responds to price, but profit depends on cost structure too.