The Measurement of U.S. Tariffs in 2025

This paper documents and compares data sources and methods that measure U.S. tariff rates in 2025. We outline key points related to accurately tracking tariff changes, such as establishing a baseline, accounting for exemptions and stacking rules, distinguishing statutory from applied rates, and managing product-level concordances and aggregation choices. The paper plots the evolution of average U.S. tariff rates using five tariff measures. Two tariff measures are constructed with publicly available data on calculated duties and customs values from official U.S. government trade data, and three tariff measures are from publicly available datasets in the academic literature that track tariff changes over the year. These measures generally document increases in tariff rates over March and April 2025, with variation in the magnitude of tariff rates depending on the tariff data source. We also document substantial variation in U.S. tariff rates across trading partners and industries. Finally, alternative aggregation approaches of U.S. tariff rates are shown to have meaningful impacts on the average U.S. tariff rate.