Trade restrictiveness indexes (TRIs) have become a staple for practitioners and policy‐makers to summarize international trade barriers. TRIs theoretically found a measure of trade restrictiveness by calculating the uniform tariff that is welfare equivalent to the observed distribution of applied tariffs within a country. Here we incorporate importer market power and exporter heterogeneity into calculations of TRIs and welfare globally. To do so, we structurally estimate a quantitative model of international trade. The structure of the model allows tractable estimation of importer and exporter welfare and TRIs for every country in the world from 1990 to 2007. Canonical estimates, which ignore exporter heterogeneity and importer market power, are shown to overstate efficiency losses from tariffs by a factor of 5 for the average importer. Additionally, by not accounting for importer market power canonical methods fail to measure substantial welfare losses to exporters that are captured by importers through tariffs. These channels are shown to significantly impact the measurement and interpretation of TRIs. To conclude, we employ the methodology to evaluate China's WTO accession and a counterfactual renegotiation of NAFTA.