DXY (US Dollar Index)

What Is the DXY?

The DXY is the most-watched measure of the U.S. dollar’s strength against other currencies. While individual currency pairs like EUR/USD or USD/JPY show the dollar’s bilateral value, the DXY aggregates the dollar’s value against a basket — providing a single number that captures the dollar’s overall trend in global foreign exchange markets.

The currency composition reflects the structure of U.S. trade in 1973, when the index was created. The euro replaced the deutsche mark, French franc, Italian lira, and Dutch guilder when the eurozone formed in 1999, but other weightings were not updated. This produces a structural distortion: China is the U.S.’s second-largest trading partner, but the Chinese yuan is not in the DXY at all. For broader real-effective-exchange-rate measures, the Federal Reserve publishes the Trade-Weighted U.S. Dollar Index, which includes the yuan and other emerging-market currencies. The DXY remains the dominant trading benchmark despite its outdated composition because of its 50+ year price history and deep derivatives market.

How Does the DXY Work?

The composition explains what’s in the index; the weighted geometric mean explains how individual currency moves translate into DXY moves. The formula is: DXY = 50.14348112 × EUR/USD^(-0.576) × USD/JPY^0.136 × GBP/USD^(-0.119) × USD/CAD^0.091 × USD/SEK^0.042 × USD/CHF^0.036.

The exponents represent the weights, with negative exponents for currencies quoted as foreign/USD (where stronger dollar means lower exchange rate) and positive exponents for currencies quoted as USD/foreign (where stronger dollar means higher exchange rate). The dominant euro weight of 57.6% means a 1% move in EUR/USD produces roughly a 0.576% inverse move in the DXY, holding other currencies constant. The yen at 13.6% and pound at 11.9% are the next most influential; the krona, franc, and Canadian dollar collectively account for less than 20%.

1. Quote the six bilateral exchange rates — EUR/USD, USD/JPY, GBP/USD, USD/CAD, USD/SEK, USD/CHF.
2. Raise each rate to its weight exponent — applying the fixed weights established in 1973 (adjusted for the euro in 1999).
3. Multiply all six raised values together — producing the weighted geometric mean.
4. Multiply by the scaling constant — 50.14348112, calibrated so the index equals 100 on March 1973.

Worked example: The DXY’s largest historical move occurred during 2014–2015 when the Federal Reserve signaled rate hikes while the European Central Bank launched quantitative easing. The DXY rose from 80 in July 2014 to 100 by March 2015 — a 25% gain in eight months driven primarily by EUR/USD falling from 1.40 to 1.05. The move pressured U.S. multinational earnings (which fell when foreign revenue translated into fewer dollars), caused commodities priced in dollars to crash, and triggered emerging-market currency crises. The DXY reached a 20-year high of 114 in September 2022 when the Fed raised rates aggressively while other central banks lagged.

DXY vs. EUR/USD

Why Is the DXY Important for Traders?

The DXY is the global gauge of dollar strength and a critical input into virtually every asset class. Commodities priced in dollars — gold, oil, copper, wheat — typically move inversely to the DXY because a stronger dollar makes these goods more expensive for non-dollar buyers, reducing demand. When the DXY rallied from 80 to 100 during 2014–2015, gold fell from $1,300 to $1,050, oil collapsed from $100 to $30, and emerging-market currencies suffered some of their worst declines on record. This inverse relationship with the S&P 500 earnings of multinational components makes the DXY essential context for commodity and EM trading.

The DXY is also a key signal for U.S. corporate earnings. Roughly 40% of S&P 500 revenue comes from outside the U.S., denominated in foreign currencies. When the DXY strengthens, foreign earnings translate into fewer dollars when reported, pressuring multinational earnings. Apple, Microsoft, Procter & Gamble, and other large multinationals routinely cite “FX headwinds” in earnings reports during strong-dollar periods. The reverse occurred in 2023 when the DXY fell from 114 to 100, providing a 5–8% earnings tailwind for U.S. multinationals.

The structural limitation is that the DXY does not reflect modern U.S. trade patterns. China, Mexico, and South Korea are major U.S. trading partners absent from the index. The Chinese yuan in particular — managed by the People’s Bank of China against an opaque basket — can diverge significantly from DXY-implied dollar strength, adding to currency volatility for traders watching only the DXY. Professional macro traders monitor both the DXY (for tradeable price action) and the broader trade-weighted dollar index (for fundamental analysis). On PrimeXBT, traders can express dollar views through forex pair CFDs like EUR/USD, GBP/USD, and USD/JPY — the same currencies that drive most of the DXY’s moves.

Key Takeaways

• The DXY measures the U.S. dollar’s value against a weighted basket of six currencies — the euro (57.6%), yen (13.6%), pound (11.9%), Canadian dollar (9.1%), krona (4.2%), and Swiss franc (3.6%).
• The DXY’s heavy euro weighting makes it essentially a EUR/USD inverse — a 1% move in EUR/USD produces approximately a 0.576% inverse move in the DXY.
• The DXY rose from 80 to 100 during July 2014 to March 2015 as the Fed signaled hikes while the ECB launched QE — a 25% move that crashed gold from $1,300 to $1,050 and oil from $100 to $30.
• The DXY reached a 20-year high of 114 in September 2022 during aggressive Fed hiking, before falling back to 100 by July 2023 as the rate-hike cycle ended.
• The DXY excludes the Chinese yuan and other major emerging-market currencies despite their importance to modern U.S. trade — making the Federal Reserve’s broader Trade-Weighted Dollar Index a more accurate measure of fundamental dollar strength.