Quick answer: The US Dollar Index (DXY, also called USDX) measures the US dollar against a fixed, weighted basket of six major currencies, with the euro making up more than half of the basket.
The dollar index turns up in market commentary almost every day as one number going up or down. Read correctly, it tells you whether a move in a USD pair is about the dollar or about the other currency. Read carelessly, it repeats what EUR/USD already showed you.
What the Dollar Index Measures
The US Dollar Index tracks the greenback against a weighted basket of six major currencies. When the index rises, the dollar has gained against the basket as a whole. When it falls, the dollar has lost ground against it.
The index is administered by ICE Data Indices, part of Intercontinental Exchange, which also lists futures on it under the symbol DX. The weights below are taken from the publisher’s ICE USDX brochure, checked on 4 November 2026.
| Currency | Weight in the index |
|---|---|
| Euro (EUR) | 57.6% |
| Japanese yen (JPY) | 13.6% |
| British pound (GBP) | 11.9% |
| Canadian dollar (CAD) | 9.1% |
| Swedish krona (SEK) | 4.2% |
| Swiss franc (CHF) | 3.6% |
The weights are fixed. According to ICE, the basket has changed once since the index was introduced in 1973, when the euro replaced several European currencies in January 1999. How past dollar cycles looked against this basket is a separate subject, covered in our guide to bearish and bullish markets.
Two things follow from the table. The Chinese yuan, the Mexican peso and the South African rand are not in the basket. And one currency outweighs the rest combined.
Why the Euro Weight Dominates the Reading
With 57.6% of the weight on the euro, the US dollar index behaves largely like an inverted EUR/USD chart. A move in the euro shows up in the index more than any other currency’s move does.
The arithmetic is simple. If EUR/USD rises 1% and the other five rates do not move, the index falls by roughly 0.57%. A 1% move in USD/JPY, with everything else unchanged, shifts it by only about 0.14%. A move of the same size in the Swiss franc barely registers.
In practice, this has two consequences:
- A falling dollar index can mean the dollar is weak across the board, or simply that the euro is strong. The index on its own does not separate the two.
- For EUR/USD traders, checking DXY is partly circular. More than half of what the index shows is the pair you are already looking at.
The worked example later in this guide shows how to strip out the euro’s share before drawing a conclusion.
How the Index Is Quoted and What a One-Point Move Means
ICE quotes the dollar index in index points to three decimal places. A rise of one point is not a fixed percentage. It is a 1% change only when the index stands at 100, and a smaller percentage whenever it stands above that.
To compare a move in DXY with a move in a currency pair, convert points into a percentage using the level on your chart:
Percentage move = points moved ÷ index level × 100
Percentages make the index comparable with EUR/USD, GBP/USD or USD/JPY, which are quoted in pips. Points alone do not.
What Moves the US Dollar Index
The dollar index moves when the dollar’s value changes against the basket, so anything that shifts demand for dollars or for the basket currencies can move it.
- US interest-rate expectations. Changes in what markets expect from the Federal Reserve tend to move the dollar against all six currencies at once.
- US economic data. Inflation and employment releases feed into those rate expectations. Release times in your time zone are on the economic calendar.
- Policy in the basket economies. A European Central Bank decision can move the index through the euro alone, given its weight. Bank of Japan decisions work the same way through the yen, with a smaller effect.
- Risk sentiment. In stressed markets, demand for dollars as a safe haven can lift the index, while demand for the yen and Swiss franc pulls in the other direction.
Several of these can move the euro and the dollar at once, so read the index next to the pairs, not in place of them.
Dollar Index Technical Analysis as a Confirmation Filter
Use the dollar index as a filter: a second check on a setup you have already found on a USD pair. It does not tell you when to enter or where to place a stop.
The question the filter answers is: is this move about the dollar? If a long EUR/USD setup relies on dollar weakness, the index should show the dollar weakening against more than just the euro.
Worked example: one EUR/USD setup
The figures below are illustrative percentage changes over one session, not market data.
A trader sees a long EUR/USD setup on the H4 chart: a pullback to a former resistance level, followed by a bullish close. The plan assumes broad dollar weakness. Over the same session, EUR/USD has risen 0.8%.
The euro’s share explains part of any DXY move: 57.6% of 0.8% is about 0.46%, how far the index would fall from the euro alone. Anything beyond that comes from the remaining currencies.
| Case A | Case B | |
|---|---|---|
| EUR/USD over the session | +0.8% | +0.8% |
| Dollar index over the session | −0.6% | −0.3% |
| Part explained by the euro | about −0.46% | about −0.46% |
| Part from the other five currencies | about −0.14% | about +0.16% |
| Reading | Dollar also weaker against the rest of the basket | Dollar stronger against the rest of the basket |
Case A supports the plan. The index fell further than the euro alone explains, so the dollar weakened against the other currencies too. GBP/USD and USD/JPY charts should show the same thing, and checking them is the next step.
Case B does not. The index fell less than the euro alone would cause, which means the dollar gained against the rest of the basket. The EUR/USD move is about the euro, not the dollar. The setup may still work, but the reason in the trade plan is wrong, so many traders would reduce size or wait for the next setup.
USD Pairs Where the Filter Helps, and Crosses Where It Does Not
The filter is useful on pairs where the dollar is one side of the quote and the other currency sits in the basket. On FXPrimus, that covers the majors:
- EUR/USD: useful, with the euro share stripped out as in the example
- GBP/USD: useful, since the pound is only 11.9% of the index and the reading is mostly about the dollar
- USD/JPY: useful for the same reason, with the pair moving in the same direction as the index rather than against it
The filter does not apply to crosses such as EUR/GBP, EUR/JPY or GBP/JPY. Neither side of those pairs is the dollar, so the index tells you nothing about them.
It is weaker for USD pairs whose other currency is outside the basket, such as USD/ZAR. The rand has its own drivers, and a flat dollar index can sit alongside a large move in USD/ZAR. To compare individual currencies directly, a currency strength meter is the better tool, and our currency correlation guide covers how USD pairs move together.
Where to Find the Dollar Index Chart
The publisher lists the index and its futures on the ICE website, including the US Dollar Index futures product page. Most charting platforms carry the cash index under the ticker DXY and the futures contract under DX.
Use the cash index for reference: a continuous futures chart can show jumps at each contract roll that the cash index does not have. Set the index chart to the same timeframe as the pair you are checking, so the swings line up.
The Limits of Reading the Index
The dollar index is a summary of six exchange rates. That makes it useful for context and limited as evidence.
- It is an inference. A basket reading suggests what the dollar is doing in general, not what any single pair will do.
- It says nothing about any one pair on its own. EUR/USD and DXY move largely together by construction, and a pair outside the basket can ignore the index.
- It lags fast moves. As a filter it confirms a move already under way. After a data release, the pair you trade moves first, and the index reflects it only once enough of the basket has moved.
- Its basket is fixed. The weights have not changed since 1999, so the index measures the dollar against a narrow group of currencies, not against every trading partner.
Dollar Index FAQ
What is the US dollar index?
A measure of the US dollar against six currencies: the euro, yen, pound, Canadian dollar, Swedish krona and Swiss franc, with fixed weights. ICE Data Indices administers it. A rising index means the dollar has gained against the basket as a whole.
What is the difference between DXY and USDX?
None in practice. Both names refer to the same US Dollar Index. ICE uses both. DXY is the ticker commonly used for the cash index, and DX is the symbol for the futures contract.
Why does the euro dominate the dollar index?
The euro carries 57.6% of the weight, more than the other five currencies combined. A 1% move in EUR/USD shifts the index by roughly 0.57%, while the same move in USD/JPY shifts it by about 0.14%.
Does the dollar index predict EUR/USD?
No. The index reflects moves in its component exchange rates, and more than half of it is EUR/USD itself. It can confirm whether a move is broad dollar strength or weakness, but it does not forecast any pair.
Is the South African rand in the dollar index?
No. The basket holds only six currencies, and the rand is not one of them. For USD/ZAR, the index gives limited context, since the rand often moves on its own drivers.
The Takeaway
Read the dollar index as a summary of the dollar against six currencies, weighted heavily towards the euro. Convert its moves into percentages, strip out the euro’s share when you check EUR/USD, and treat a mismatch as a reason to recheck the trade plan. A PrimusDEMO account lets you practise the check on EUR/USD, GBP/USD and USD/JPY with the index chart open alongside, without real money.
Open a PrimusDEMO account | Read the currency correlation guide
Risk disclosure. This article is for informational and educational purposes only and is not financial advice, legal advice or tax advice. Trading forex and CFDs carries a high risk of loss and is not suitable for every investor. Past performance does not guarantee future results. The dollar index is described here as a reference measure; the percentage changes in the worked example are illustrative and are not market data or a forecast. Basket weights are as published by ICE Data Indices and may be revised by the publisher. Review the full terms and conditions, the Client Agreement and the Risk Disclosure before trading.