Compute the midpoint (arc) elasticity of quantity Q with respect to any X — price, income, or another price.
| Arc elasticity | – |
Use this elasticity calculator for own-price, income, or cross-price elasticity: change what X is. The midpoint formula is less sensitive to which point you call start.
Arc elasticity = (ΔQ / average Q) ÷ (ΔX / average X), where average Q = (Q0 + Q1) / 2 and likewise for X. X must change. A negative own-price elasticity is the usual downward-sloping demand; a positive cross-price elasticity suggests substitutes.
Q start: Quantity at the first point.
Q end: Quantity at the second point.
X start: Price, income, or other price at the first point.
X end: The same X at the second point.
Arc elasticity: The midpoint elasticity (unitless).
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