US Dollar Index (DXY): What the Basket Actually Measures
One number is quoted more than any other when the subject is the strength of the dollar, and it is almost always described the same way: the dollar against a basket of major world currencies.
The basket part is right. The world part is not. What the index actually contains, and what it leaves out, changes what a move in it can be taken to mean.
Key takeaways
- The index holds six currencies at fixed weights: euro 0.576, yen 0.136, pound 0.119, Canadian dollar 0.091, Swedish krona 0.042, Swiss franc 0.036.
- It contains no Chinese renminbi and no Mexican peso, which together carry more than a quarter of the Federal Reserve broad dollar index.
- ICE Futures U.S. states there are no regularly scheduled adjustments or rebalancings. The basket has been changed once, when the euro was introduced.
- The Swedish krona holds 4.2 per cent of the index against 0.624 per cent of the Federal Reserve measure, close to seven times the weight trade data supports.
- With the euro at 57.6 per cent of a geometric average, most of a day’s move in the index is EUR/USD inverted, so it is weak confirmation for a euro trade.
- The index is a market convention with a 1973 reference point, not a measurement of the dollar in the world economy today.
Table of contents
- What the Dollar Index Is and Who Calculates It
- The Exact Basket, the Weights and the Formula
- Why It Is Not a Measure of the Dollar Against the World
- How the Federal Reserve Weights the Dollar Instead
- The Euro Problem: Using DXY to Confirm a EUR/USD Trade
- Why the Basket Never Gets Rebalanced
- Who This Page Is Not For
- Frequently Asked Questions
What the Dollar Index Is and Who Calculates It
The dollar index is not published by a central bank and is not an official statistic. It is an exchange product with a documented methodology.
ICE Futures U.S. describes it as a geometrically averaged calculation of six currencies weighted against the US dollar. The value is compared against the dollar relative to March 1973, when the major trading nations allowed their currencies to float freely against each other.
The origin is often misstated. The index was originally developed by the US Federal Reserve in 1973, and since futures trading on it began in 1985 ICE Futures U.S. has compiled, maintained, determined and weighted its components and caused it to be calculated and disseminated.
The exchange symbol for the futures contract is DX. The symbol most traders use, DXY, is Bloomberg’s, which is also where the nickname Dixie comes from.
Calculation is continuous rather than periodic. ICE states the index is calculated in real time approximately every 15 seconds from a multi-contributor feed of spot prices, using the mid-point between the top of the book bid and offer in the component currencies.
The Exact Basket, the Weights and the Formula
The weights are published by the administrator, and they are exact rather than rounded conveniences.
| Currency | Weight in the index |
|---|---|
| Euro (EUR) | 0.576 |
| Japanese yen (JPY) | 0.136 |
| British pound (GBP) | 0.119 |
| Canadian dollar (CAD) | 0.091 |
| Swedish krona (SEK) | 0.042 |
| Swiss franc (CHF) | 0.036 |
The formula is published in full, and it is rarely reproduced outside the exchange documentation. The index equals 50.14348112 multiplied by EURUSD raised to the power minus 0.576, USDJPY to 0.136, GBPUSD to minus 0.119, USDCAD to 0.091, USDSEK to 0.042 and USDCHF to 0.036.
Two features of that expression matter more than the constant. The exponent carries a negative sign where the dollar is the quote currency and a positive sign where the dollar is the base currency, which is why EUR/USD and GBP/USD enter with the opposite sign to USD/JPY.
The second is that the terms are multiplied rather than added. A geometric average is not the weighted arithmetic mean most descriptions imply, and percentage changes in the components do not sum neatly into the index change.
The basket has a longer history than six currencies suggests. Before the euro existed the index held ten: the current five non-euro members plus the West German mark, the French franc, the Italian lira, the Dutch guilder and the Belgian franc.
Why It Is Not a Measure of the Dollar Against the World
Every currency in the basket is European, Japanese or Canadian. There is no renminbi, no peso, no won, no rupee and no real.
That is not a small omission, and the size of it can be stated precisely rather than asserted, because the Federal Reserve publishes weights derived from actual trade.
In the Federal Reserve broad dollar index, using the total trade weights published as of 2 February 2026, Mexico carries 14.801 per cent and China 10.891 per cent. Between them that is more than a quarter of the measure, and none of it appears in the dollar index.
The distortion runs the other way too. The Swedish krona carries 4.2 per cent of the dollar index and 0.624 per cent of the Federal Reserve broad index, roughly seven times the weight the trade data supports.
| Economy | Weight in the dollar index | Weight in the Fed broad index, 2026 |
|---|---|---|
| Euro area | 57.6 per cent | 21.007 per cent |
| Mexico | Not included | 14.801 per cent |
| Canada | 9.1 per cent | 12.769 per cent |
| China | Not included | 10.891 per cent |
| United Kingdom | 11.9 per cent | 5.246 per cent |
| Japan | 13.6 per cent | 5.182 per cent |
| Sweden | 4.2 per cent | 0.624 per cent |
Read as a market instrument, the index is perfectly coherent: it is a defined, tradable basket with a long price history. Read as a statement about the dollar in the world economy, it describes a trading pattern that has moved on.
How the Federal Reserve Weights the Dollar Instead
The Federal Reserve publishes its own dollar indexes, and comparing the two designs shows what the older one is not trying to do.
The broad index is a weighted average of the foreign exchange value of the dollar against the currencies of a broad group of US trading partners, and it is split further into advanced foreign economies and emerging market economies.
Its weights are not frozen. The Federal Reserve states that the currency weights are updated and revised annually, and in unusual circumstances may be revised at other times; the set preceding the current one ran from 24 March 2025 to 30 January 2026.
That single design choice separates the two measures. One is anchored to a fixed basket agreed in the 1970s and adjusted once since; the other is re-derived from trade data each year and changes as trading relationships change.
Neither is wrong. They answer different questions, and a chart of one is not evidence about the other, which is worth remembering when a commentary switches between them without saying so. The wider relationships involved are covered in our guide to intermarket analysis.
The Euro Problem: Using DXY to Confirm a EUR/USD Trade
The euro is 57.6 per cent of the basket, which is more than the other five currencies together.
That has a consequence the weight tables do not spell out. A large share of what the index does on any given day is the euro moving against the dollar, expressed the other way up.
So a trader who takes a EUR/USD position and then looks at the index for confirmation is, for the most part, looking at the same position again. The two charts agreeing is close to arithmetic rather than evidence.
The index carries more information for a pair that is not in it at all. For USD/MXN or USD/CNH the index says nothing directly, because neither currency is a component.
Where a second opinion is genuinely useful, it has to come from a source that is not already inside the first one. Our guide to currency correlation covers how to test whether two series are actually independent, and our guide to major currency pairs covers how the pairs themselves are grouped.
Why the Basket Never Gets Rebalanced
The obvious question is why the composition has not been brought up to date, and the answer is in the administrator’s own documentation rather than in speculation.
ICE states that there are no regularly scheduled adjustments or rebalancings of the index, that it was adjusted once when the euro was introduced as the common currency of the European Union bloc, and that it monitors the methodology and makes adjustments as and when necessary.
Continuity is the point. Futures contracts have been listed on the index since 20 November 1985 and options since 3 September 1986, and a basket that changed every year would break the comparability of that price history.
The trade-off is stated plainly enough by the two documents side by side: the index buys a stable, tradable, long-running series at the cost of describing a trade pattern that is decades old. Whether that matters depends entirely on what the number is being used for.
Who This Page Is Not For
This page does not forecast the dollar, and it offers no view on whether the index is currently high or low.
It gives no levels, no entry or exit rules, and no method for trading the index or its futures contract.
Anyone looking for a signal derived from the index will not find one here. The material describes what the number is made of and what can honestly be inferred from a move in it.
Risk warning. Trading foreign exchange, index futures and contracts for difference carries a high level of risk and can result in the loss of your entire deposit. Index values and weights described here are matters of published methodology, not indications of future value. Nothing on this page is investment advice or a recommendation to trade any instrument.
Frequently Asked Questions
What is the US dollar index?
The US dollar index is a single number tracking the dollar against a fixed basket of six currencies. ICE Futures U.S. describes it as a geometrically averaged calculation of six currencies weighted against the US dollar, referenced to March 1973. It was originally developed by the US Federal Reserve in 1973, and ICE Futures U.S. has compiled and weighted its components since futures trading on it began in 1985.
Which currencies are in the DXY basket?
Six: the euro at a weight of 0.576, the Japanese yen at 0.136, the British pound at 0.119, the Canadian dollar at 0.091, the Swedish krona at 0.042 and the Swiss franc at 0.036. Before the euro existed the index held ten currencies, the current five non-euro members plus the West German mark, the French franc, the Italian lira, the Dutch guilder and the Belgian franc. The euro replaced those five, and their combined weight carried across to it.
Does the dollar index include the Chinese renminbi?
No. Neither the renminbi nor the Mexican peso appears in the basket, and no currency has been added since the euro replaced five European currencies in 1999. For comparison, in the Federal Reserve broad trade-weighted dollar index, using the weights published as of 2 February 2026, Mexico carries 14.801 per cent and China 10.891 per cent. Those two economies account for more than a quarter of the Federal Reserve measure and nothing at all in the dollar index.
How is the dollar index calculated?
ICE publishes the formula in full. The index equals 50.14348112 multiplied by EURUSD raised to the power minus 0.576, USDJPY to the power 0.136, GBPUSD to minus 0.119, USDCAD to 0.091, USDSEK to 0.042 and USDCHF to 0.036. The exponent is negative where the dollar is the quote currency and positive where it is the base currency. ICE calculates the index in real time roughly every 15 seconds from a multi-contributor feed, using the mid-point between the top of the book bid and offer.
Is DXY the same as the Federal Reserve dollar index?
No, and the two are built on different principles. The dollar index holds six currencies at weights that have not changed since the euro was introduced, and ICE states there are no regularly scheduled adjustments or rebalancings. The Federal Reserve publishes broad, advanced-economy and emerging-market dollar indexes whose currency weights are updated and revised annually from trade data. Two indexes can therefore describe the same dollar and disagree about how strong it has been.