New update of the World Income Inequality Database

The UNU-WIDER World Income Inequality Database ― widely known by its acronym WIID ― provides the most comprehensive set of income inequality statistics available. It presents detailed information on income inequality for developed, developing, and transition countries. The latest version of the WIID can be downloaded here.

The newest version is part of the 2019–23 UNU-WIDER work programme and builds on December, 2019 updates. It is now more fully harmonized with source data. It also includes new data points and corrects minor inconsistencies.

The WIID has long been used for research on global inequality, to analyse inequality trends across countries and to study the relationships between inequality and, for example, economic growth, foreign direct investment, real exchange rates, institutional development, labour regulations, economic sanctions, public sector expansion, political conflict, religiosity, and skilled migration.

It was initially compiled in 1997–99 for the UNU-WIDER/UNDP project Rising income inequality and poverty reduction: Are they compatible? and published in September of 2000.

In WIID4, the observations are current to the year 2018 and cover 200 countries and more than 11,000 data points in total. There are now more than 3,600 unique country-year observations in the database.

About the database
Observations by variable type   Number of observations
Total observations 11,826
Gini coefficients 11,747
Income distribution by quintile shares 7,349
Income distribution by decile shares 6,567


Time span Number of observations
Total observations 11,826
Before 1960 311
1960–69 689
1970–79 849
1980–89 1,440
1990–99 2,630
2000–09 3219
2010–18 2,688