🧪 Economics International Trade Simulation

This simulator models a single, well-defined piece of international trade theory: how a currency depreciation and an import tariff move a country's trade balance over time. Because contracts, shipping and buying habits are sticky, import and export volumes don't move the moment prices change — they drift toward their new level over months, while the price of imports jumps immediately. That gap produces the "J-curve": the trade balance first worsens because the import bill rises before quantities adjust, then recovers (or doesn't) once trade volumes catch up. Whether the long run recovery actually improves the trade balance is governed by the Marshall-Lerner condition, η_x + η_m > 1 — the sum of the export and import price elasticities must exceed one. Adjust the depreciation, tariff, elasticities and contract-adjustment speed, then press Play to watch the 3D export and import flows speed up or slow down while the trade-balance path traces its J-shape in real time.