Dollar Index DXY: What It Measures and Its Limits

Key Takeaways

• DXY is 57.6% euro, making it essentially an inverse EUR/USD with smaller exposures to yen (13.6%), pound (11.9%), CAD (9.1%), SEK (4.2%), and CHF (3.6%).
• The weights were fixed in 1999 when the euro replaced individual European currencies; DXY has no yuan, peso, or any emerging-market currency.
• The Fed's trade-weighted broad dollar index (H.10) is more comprehensive and updates weights periodically; it is the better reference for EM debt and export analysis.
• DXY is nominal, it does not adjust for inflation differentials; real effective exchange rates can show dollar over/undervaluation even when DXY looks flat.

What It Is

DXY is a geometrically averaged basket of six currencies weighted against the US dollar. According to the ICE methodology document, the current weights are euro 57.6 percent, Japanese yen 13.6 percent, British pound 11.9 percent, Canadian dollar 9.1 percent, Swedish krona 4.2 percent, and Swiss franc 3.6 percent. The index was launched by the US Federal Reserve in March 1973 at a base value of 100 and is now calculated and maintained by ICE Futures US.

The weights were set based on 1970s trade flows and have been essentially fixed since the euro replaced the individual European currencies in 1999. That means the index tracks the dollar against a slice of developed Europe plus Japan, Canada, and Switzerland, and nothing else.

The Intuition

When analysts say "the dollar is up," they usually mean DXY is up. A rising DXY means the dollar has strengthened against this specific basket. A falling DXY means the opposite. Because the euro dominates the weight, DXY is often described, not unfairly, as an "inverse EUR/USD with extras."

Dollar strength matters beyond FX desks. Commodities priced in dollars (oil, gold, copper) tend to face a headwind when the dollar rallies, since they become more expensive for non-dollar buyers. Emerging-market borrowers with dollar debt feel their liability grow. US multinationals see foreign earnings translate to fewer dollars. These links are tendencies, not laws, but they show why DXY is on every macro dashboard.

How It Works

The DXY formula is a product of bilateral exchange rates, each raised to a power that matches its weight:

DXY = 50.14348112 x EURUSD^-0.576 x USDJPY^0.136 x GBPUSD^-0.119
             x USDCAD^0.091 x USDSEK^0.042 x USDCHF^0.036

Currencies where the dollar is the quote currency (EURUSD, GBPUSD) get a negative exponent, since a higher quote means a weaker dollar. Currencies where the dollar is the base (USDJPY, USDCAD, USDSEK, USDCHF) get a positive exponent. The constant anchors the index at 100 on its March 1973 start date.

A more economically meaningful benchmark is the Federal Reserve's Trade-Weighted Broad Dollar Index, published in the H.10 statistical release. The broad index measures the dollar against the currencies of a much wider set of trading partners, including the Chinese yuan, Mexican peso, and other emerging markets. Weights are updated periodically, most recently on March 24, 2025, and reflect actual US trade in goods and services.

The Fed also publishes sub-indexes: the Advanced Foreign Economies (AFE) index for developed partners, and the Emerging Market Economies (EME) index. For serious macro work, especially research on how the dollar affects US exports or EM debt, analysts usually prefer the Fed broad index to DXY.

Worked Example

Suppose EUR/USD is 1.10, USD/JPY is 150, GBP/USD is 1.27, USD/CAD is 1.36, USD/SEK is 10.50, and USD/CHF is 0.88. Plugging these into the formula:

DXY = 50.14348112 x (1.10)^-0.576 x (150)^0.136 x (1.27)^-0.119
             x (1.36)^0.091 x (10.50)^0.042 x (0.88)^0.036

This evaluates to roughly 105. A reading of 105 means the basket-weighted dollar is 5 percent above its March 1973 base. A move from 105 to 107 is about a 1.9 percent dollar appreciation against this specific set of currencies, nothing more.

Over the same period the Fed broad index might tell a different story if, for example, the dollar weakened against the yuan while strengthening against the euro. The two indexes can diverge by several percent a year.

Common Mistakes

1. Treating DXY as "the dollar." DXY has no yuan, no peso, no won, no real, and no rupee. Together those currencies represent a huge share of actual US trade. If you care about the dollar's effect on US exports or global EM flows, DXY is a narrow proxy and the Fed broad index is the better reference.

2. Assuming DXY moves translate one for one to every asset. Oil, gold, and EM equities have historical negative correlations with DXY, but those correlations are noisy and vary by regime. A 1 percent DXY move does not imply a 1 percent commodity move in the opposite direction. Correlation is not mechanics.

3. Ignoring that DXY is nominal. The index is a nominal exchange-rate measure. It does not adjust for inflation differentials. Real effective exchange rates, which strip out relative inflation, can show the dollar is overvalued or undervalued even when DXY looks flat.

4. Forgetting the fixed-weight artifact. Because weights were locked in 1999, DXY structurally underweights China and Mexico relative to current US trade patterns. Reading a DXY rally as "the dollar is broadly strong" can be misleading when the euro is simply weak on its own story.

Frequently Asked Questions

What currencies are in the DXY? DXY tracks six currencies: euro (57.6%), Japanese yen (13.6%), British pound (11.9%), Canadian dollar (9.1%), Swedish krona (4.2%), and Swiss franc (3.6%). There is no Chinese yuan, Mexican peso, or any emerging-market currency. The weights were locked in 1999 when the euro replaced individual European currencies.

Why is the Fed's broad dollar index better than DXY for trade analysis? The Fed's trade-weighted Broad Dollar Index (H.10) includes the currencies of a much wider set of U.S. trading partners, including the Chinese yuan and Mexican peso, with weights updated periodically to reflect actual U.S. goods and services trade. DXY's fixed 1999 weights structurally underweight China and Mexico, two of America's largest trading partners, making it a misleading proxy for the dollar's effect on U.S. exports or import prices.

Does a strong dollar hurt commodity prices? Commodities priced in dollars, oil, gold, copper, tend to face a headwind when the dollar rallies, since they become more expensive for non-dollar buyers, reducing demand. The relationship exists but is noisy and varies by regime. A 1% DXY move does not mechanically translate into a 1% opposite commodity move; treat the correlation as a tendency, not a law.

What does a DXY reading above or below 100 mean? DXY was launched at 100 in March 1973. A reading above 100 means the basket-weighted dollar is stronger than its 1973 starting value; below 100 means it is weaker. The index has ranged from near 70 (2008) to above 160 (1985). These levels have no intrinsic significance other than that historical context, the index is nominal and does not adjust for inflation differentials across countries.

Can the DXY be traded directly? Yes, through DXY futures on ICE Futures U.S. and through options on those futures. Various ETFs and ETNs also track dollar index performance, though they may replicate a variant index. For FX desks and macro traders, DXY futures are a common single-instrument proxy for a broad dollar long or short, accepting the index's narrow developed-market composition as a limitation.

Sources

1. Intercontinental Exchange. "U.S. Dollar Index Contracts FAQ." https://www.ice.com/publicdocs/futures_us/ICE_Dollar_Index_FAQ.pdf
2. Intercontinental Exchange. "ICE FX Indices Methodology." https://www.ice.com/publicdocs/data/ICE_FX_Indexes_Methodology.pdf
3. Board of Governors of the Federal Reserve System. "Foreign Exchange Rates - H.10 - Currency Weights." https://www.federalreserve.gov/releases/h10/weights/default.htm
4. Board of Governors of the Federal Reserve System. "Revisions to the Federal Reserve Dollar Indexes." https://www.federalreserve.gov/econres/notes/feds-notes/revisions-to-the-federal-reserve-dollar-indexes-20190115.html

Disclaimer

This article is educational content only and is not financial advice. Nothing here is a recommendation to buy, sell, or hold any security. Consult a licensed advisor before making investment decisions.