The U.S. Dollar Index (USDX, DXY, DX) is an index (or measure) of the value of the United States dollar relative to a basket of foreign currencies, often referred to as a basket of U.S. trade partners' currencies. The Index goes up when the U.S. dollar gains "strength" (value) when compared to other currencies.

The index is maintained and published by ICE (Intercontinental Exchange, Inc.), with the name "U.S. Dollar Index" a registered trademark.

It is a weighted geometric mean of the dollar's value relative to following select currencies:

• Euro (EUR), 57.6% weight.
• Japanese yen (JPY) 13.6% weight.
• Pound sterling (GBP), 11.9% weight.
• Canadian dollar (CAD), 9.1% weight.
• Swedish krona (SEK), 4.2% weight.
• Swiss franc (CHF) 3.6% weight.