Dollar Index
The US Dollar Index, often called DXY, measures the value of the US dollar against a basket of six major currencies. A rising index means the dollar is strengthening against them; a falling index means it is weakening.
How the Dollar Index is built
The index started in 1973 with a base value of 100. It compares the dollar with the euro, the Japanese yen, the British pound, the Canadian dollar, the Swedish krona and the Swiss franc. Each currency has a fixed weight, and the euro dominates with more than half of the basket. The weights have not changed since the euro replaced several European currencies in 1999.
A reading of 110 means the dollar is worth about 10% more against this basket than at the 1973 starting point. A reading of 90 means it is worth about 10% less.
What moves the dollar
Interest rates are a major driver. When US rates rise relative to those in Europe or Japan, holding dollars pays more, and demand for the currency tends to grow. The dollar also often strengthens in times of global stress, because investors and companies seek it as a widely accepted safe currency and because much international debt is owed in dollars.
Trade balances, growth differences and political events matter too, but no single factor explains every move.
Why crypto traders watch it
Most crypto is priced in dollars. If the dollar gains value, the same coin is worth fewer dollars unless demand rises. In many periods a strong dollar has also coincided with tighter financial conditions and risk-off moods, which have weighed on riskier assets. A weakening dollar has often come with easier conditions.
Say the index rises from 100 to 105 over a few months while US rates climb. Investors earn more on dollar cash, and some reduce holdings in volatile assets. That pattern has appeared several times, but the relationship with crypto is loose and has broken down in some periods.
Limits of the indicator
DXY covers only six currencies from developed economies. It leaves out China, Mexico and other major trading partners, so it is not a complete picture of the dollar's global strength. Treat it as one macro indicator among several, not as a trading signal on its own.
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Frequently asked questions
Does a strong dollar mean Bitcoin will fall?
Not necessarily. A rising dollar has often coincided with weaker crypto prices, but the link is a tendency, not a rule, and other factors can outweigh it.
Which currencies are in the Dollar Index?
The euro, Japanese yen, British pound, Canadian dollar, Swedish krona and Swiss franc, with the euro making up the largest share.
What does DXY stand for?
DXY is the common ticker symbol for the US Dollar Index. It is not an abbreviation of a longer name.
Related terms
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