Interactive calculator
Tariff Revenue and Welfare Calculator
A per-unit tariff raises the domestic price of an imported good. Enter the world price, the tariff, and import quantities before and after: the calculator shows government revenue (tariff x post-tariff imports), the consumer surplus loss, and the two deadweight-loss triangles from distorted production and consumption. In this release this page is powered by the closest available interactive widget; a dedicated widget for this topic is planned.
Price Elasticity of Demand
Midpoint (arc) formula
- Average quantity: (Q₁ + Q₂) ÷ 2 = (100.00 + 140.00) ÷ 2 = 120.00
- %ΔQ = (Q₂ − Q₁) ÷ avg Q = 40.00 ÷ 120.00 = 0.3333 (33.33%)
- Average price: (P₁ + P₂) ÷ 2 = (10.00 + 8.00) ÷ 2 = 9.00
- %ΔP = (P₂ − P₁) ÷ avg P = -2.00 ÷ 9.00 = -0.2222 (-22.22%)
- E = %ΔQ ÷ %ΔP = 0.3333 ÷ -0.2222 = -1.500
- Classification by |E| = 1.500: elastic — quantity responds more than proportionally to price.
Using averages as the base removes the direction problem: going from P₁ to P₂ gives the same magnitude as going from P₂ to P₁. The negative sign just reflects the law of demand — classification uses the absolute value.
How to use it
Enter the world price and the tariff per unit.
Enter import quantities before and after the tariff.
Read revenue, consumer loss, and deadweight loss.
What you will learn
- Compute tariff revenue.
- Identify the welfare effects of a tariff.
- Explain why tariffs create deadweight loss.