What Is the US Dollar Index?

By Colin Dodds · August 10, 2023 · 6 minute read

We’re here to help! First and foremost, SoFi Learn strives to be a beneficial resource to you as you navigate your financial journey. Read more We develop content that covers a variety of financial topics. Sometimes, that content may include information about products, features, or services that SoFi does not provide. We aim to break down complicated concepts, loop you in on the latest trends, and keep you up-to-date on the stuff you can use to help get your money right. Read less

What Is the US Dollar Index?

The U.S. dollar index, also called the USDX, tracks the value of the dollar compared with six major world currencies — specifically those of the United States’ most significant trading partners.

The USDX fluctuates based on the exchange rates that the dollar maintains with those currencies. Investors and traders use the USDX as a quick way to track the relative value of the dollar and to manage potential currency risks in their portfolio.

There are also several futures and options strategies trading on the New York Board of Trade that allow sophisticated investors to bet that the USDX will go up or down. For investors who want to hedge their currency risks, or just speculate, they can invest in the U.S. dollar index through mutual funds, exchange-traded funds (ETFs), or options.

How the US Dollar Index Is Calculated

Currently, the U.S. dollar index is calculated using the exchange rates of six currencies: the Euro (EUR), the Japanese yen (JPY), the Canadian dollar (CAD), the British pound (GBP), the Swedish krona (SEK), and the Swiss franc (CHF). Given that 19 countries in the European Union use the euro, EUR is the most significant component of the index, representing 57.6% of the basket.

By contrast the yen comprises 13.6% of the index, followed by the British pound (11.9%), the Canadian dollar (9.1%), the Swedish krona (4.2%), and finally the Swiss franc (3.6%).

The U.S. dollar has long been considered the world’s reserve currency, and the index tracks where five of those six currencies stood in relation to the U.S. dollar in 1973 (the euro was added to the index in 1999). At its inception, the U.S. dollar index was set at 100. When the index is over 100, then the dollar is considered strong, and it may be considered weak depending on how far below 100 it falls.

The strength or weakness of a dollar impacts many aspects of the economy. A weak dollar increases the prices that companies pay for globally traded commodities, which contributes to inflation by raising the prices consumers pay for everyday items. A strong dollar makes the goods produced in the U.S. more expensive to overseas consumers, and can hurt exports over time.

💡 Quick Tip: Investment fees are assessed in different ways, including trading costs, account management fees, and possibly broker commissions. When you set up an investment account, be sure to get the exact breakdown of your “all-in costs” so you know what you’re paying.

The History of the US Dollar Index

When World War II ended in 1945, the United States found itself in a position of unusual strength. Like many countries, the U.S. had suffered enormous casualties, yet its industries, cities, and overall economy had survived the war more or less intact. So it was that in July of 1944, over 700 delegates from 44 countries met in Bretton Woods, NH, to create a roadmap for a more efficient foreign exchange system that would help establish a resilient post-war global economy.

The Bretton Woods Agreement that emerged from this historic conference created a system whereby gold became the basis for the U.S. dollar, and other currencies were pegged to the value of the dollar. The International Monetary Fund and the World Bank were also established as a result of Bretton Woods.

The new global currency system included a promise from the participating countries that their central banks would establish fixed exchange rates between their own currencies and the U.S. dollar. Each agreed that if their currency weakened, they would order their central bank to buy up the currency until its value stabilized relative to the dollar. And if their currency grew too strong compared with the dollar, their central bank would issue more currency until the value dropped and its relationship with the dollar stabilized.

The terms of the Bretton Woods Agreement were so far-reaching that it took until 1958 to be fully implemented. Still, the decision to keep the dollar pegged to gold proved challenging for the U.S. In 1971, when the gold owned by the U.S. government could no longer cover the number of dollars in circulation, President Richard M. Nixon was forced to reduce the dollar’s value relative to gold. The Bretton Woods System collapsed in 1973.

With the end of the Bretton Woods System, countries and their central banks took a wide range of approaches to how they valued their currency. After 1973, each country’s currency had its own value, adjusted through trade, government interventions, and the policies of central banks. To track the value of the dollar against this backdrop of currency valuations, the U.S. dollar index came into being.

When it launched, it had a base of 100, representing the dollar’s value versus the currencies of its major trading partners. Since then, the index has fluctuated relative to that base. Over the last five years, for example, the U.S. dollar index reached a high of 102.39 on December 1, 2016, and a low of 89.13 on January 1, 2018. The value of the index is considered a fair indication of the dollar’s position in global markets. And investors can also use it to trade.

💡 Quick Tip: How to manage potential risk factors in a self directed investment account? Doing your research and employing strategies like dollar-cost averaging and diversification may help mitigate financial risk when trading stocks.

How to Trade the US Dollar Index

Investors who want to bet on the rise or fall of the dollar’s value, or who simply want to hedge it as part of a broader strategy, can trade the U.S. dollar index the same way they trade an equity index like the S&P 500. The U.S. dollar index is popular among foreign exchange (FX) traders who don’t have the time or resources to monitor the movements between the dollar and the other currencies in the index.

Anyone who tracks global trade will notice that two major currencies are missing from the index: Neither the Chinese yuan (CNY) or the Mexican peso (MXN) are in the USDX. Historically the USDX has only been adjusted once since its inception — in 1999 when the euro was added, and certain of the currencies the euro had replaced were then removed from the index. Still, it’s likely that at some point the USDX could be adjusted a second time to include CNY and MXN, given their status as significant trading partners with the United States.

Investing with SoFi

Most investors know that a bond index or equity index is typically comprised of many constituent companies; similarly, the U.S. dollar index is comprised of six global currencies. It tracks the value of the dollar relative to those currencies, and fluctuates based on the exchange rates that the dollar maintains with those currencies. You can use the USDX as a way to track the relative value of the dollar, to manage potential currency risks in a portfolio, and to trade.

Ready to invest in your goals? It’s easy to get started when you open an investment account with SoFi Invest. You can invest in stocks, exchange-traded funds (ETFs), mutual funds, alternative funds, and more. SoFi doesn’t charge commissions, but other fees apply (full fee disclosure here).

Invest with as little as $5 with a SoFi Active Investing account.

Photo credit: iStock/FG Trade

SoFi Invest®
SoFi Invest encompasses two distinct companies, with various products and services offered to investors as described below: Individual customer accounts may be subject to the terms applicable to one or more of these platforms.
1) Automated Investing and advisory services are provided by SoFi Wealth LLC, an SEC-registered investment adviser (“SoFi Wealth“). Brokerage services are provided to SoFi Wealth LLC by SoFi Securities LLC.
2) Active Investing and brokerage services are provided by SoFi Securities LLC, Member FINRA (www.finra.org)/SIPC(www.sipc.org). Clearing and custody of all securities are provided by APEX Clearing Corporation.
For additional disclosures related to the SoFi Invest platforms described above please visit SoFi.com/legal.
Neither the Investment Advisor Representatives of SoFi Wealth, nor the Registered Representatives of SoFi Securities are compensated for the sale of any product or service sold through any SoFi Invest platform.

Third-Party Brand Mentions: No brands, products, or companies mentioned are affiliated with SoFi, nor do they endorse or sponsor this article. Third-party trademarks referenced herein are property of their respective owners.

Financial Tips & Strategies: The tips provided on this website are of a general nature and do not take into account your specific objectives, financial situation, and needs. You should always consider their appropriateness given your own circumstances.


All your finances.
All in one app.

SoFi QR code, Download now, scan this with your phone’s camera

All your finances.
All in one app.

App Store rating

SoFi iOS App, Download on the App Store
SoFi Android App, Get it on Google Play

TLS 1.2 Encrypted
Equal Housing Lender