The US dollar index and gold explained

Gold is priced in US dollars, so the strength of the dollar is one of the first things gold traders check. The usual yardstick is the US Dollar Index, often called DXY. This guide explains what the index is, why gold and the dollar tend to move in opposite directions, why real interest rates matter so much, and when the usual relationship breaks down.

What the US Dollar Index is

The US Dollar Index measures the value of the dollar against a basket of six major currencies. It was set at 100 when it was launched in the early 1970s, so a reading above 100 means the dollar is stronger against the basket than at the start and a reading below 100 means it is weaker. The index is published by ICE, and futures on it trade on the ICE exchange.

The basket is fixed and heavily weighted towards the euro, which is worth remembering: a move in EUR/USD alone can move the index a lot.

Currency	Approximate weight in the index
Euro (EUR)	57.6%
Japanese yen (JPY)	13.6%
Pound sterling (GBP)	11.9%
Canadian dollar (CAD)	9.1%
Swedish krona (SEK)	4.2%
Swiss franc (CHF)	3.6%

Because the weights have not changed since the euro replaced several of the original currencies, the index does not include the currencies of some of the largest US trading partners today, such as China and Mexico. It is a useful gauge of the dollar against major developed currencies, not a complete picture of the dollar.

Why gold and the dollar often move in opposite directions

Gold is quoted as XAU/USD, the number of dollars needed to buy one troy ounce. Several forces push gold and the dollar in opposite directions:

• Price conversion. When the dollar weakens, gold becomes cheaper for buyers using euros, yen or other currencies, which can lift demand and the dollar price.
• Competing safe stores of value. Gold and the dollar both attract money in some kinds of uncertainty. When investors prefer the dollar and dollar assets, gold can lose out, and the reverse is also true.
• Interest rates. Rising US rates tend to lift the dollar and make holding gold, which pays no interest, less attractive.

The result is a tendency, not a rule. Over many periods a stronger dollar has coincided with weaker gold and a weaker dollar with stronger gold, but the strength of the link varies a lot.

Real yields: the deeper driver

Many analysts see real interest rates as the most important single driver of gold. The real yield is the return on a bond after inflation. In the US it is often tracked through the yield on Treasury Inflation Protected Securities, known as TIPS.

The logic is about opportunity cost. Gold pays no interest. When real yields are high, investors give up a meaningful inflation adjusted return by holding gold instead of bonds, so gold tends to struggle. When real yields are low or negative, that cost shrinks and gold tends to be more attractive. Because higher real yields usually also support the dollar, this is one reason the dollar and gold so often move in opposite directions. Our interest rates and currencies guide explains how rate expectations form.

When the relationship breaks down

Gold and the dollar can rise together, or fall together, for long stretches. Common reasons include:

Situation	What can happen
Acute market stress	Investors buy both the dollar and gold as safe havens at the same time
Strong central bank gold buying	Official purchases can support gold even when the dollar is firm
Weakness in other currencies	The dollar index can rise because the euro or yen is weak, while gold holds up
Forced selling	In a sharp sell off, traders may sell gold to raise cash, so gold falls with other assets

For this reason it is risky to trade gold purely as the mirror image of the dollar. Treat the dollar as one input alongside real yields, risk sentiment and gold specific news.

How traders use the dollar index with gold

• Context. Check whether the dollar is broadly strong or weak before looking at a gold chart.
• Confirmation. A gold move that comes with a clear dollar move in the opposite direction may have broader support than one that does not.
• Event risk. US data such as inflation, jobs and Federal Reserve decisions often move both the dollar and gold at the same moment.
• Divergence. If the dollar and gold both rise, ask why. It often points to stress or a gold specific driver.

Our gold market basics guide covers contract sizes and trading hours, and the gold pip and point value calculator shows what a gold move is worth for your position size.

Reading the index on a chart

Many charting platforms show the dollar index under a symbol such as DXY or USDX, and some brokers offer a CFD based on it. When you compare it with gold, use the same timeframe for both and look at the direction of the trend rather than individual candles. Overlaying the two lines, or placing the charts one above the other, makes it easy to see when they move in opposite directions and when they do not.

Because the euro makes up more than half of the index, it is also worth glancing at EUR/USD itself. If the index is rising mainly because the euro is weak, the effect on gold can be smaller than a broad dollar rally against every currency. Checking USD/JPY as well gives a quick view of the second largest weight.

A worked example

Suppose US inflation data comes in higher than expected. Traders now expect the Federal Reserve to keep rates higher for longer. US yields rise, the dollar index climbs and gold falls as its opportunity cost increases. A few days later a weaker jobs report reverses those expectations: yields drop, the dollar eases and gold recovers. The point is not the exact size of each move, which varies every time, but the chain of cause and effect from data to rate expectations to the dollar and gold.

Dollar and gold checklist

• I know the dollar index is weighted mostly towards the euro.
• I check the broad dollar trend before trading gold.
• I watch real yields as well as the dollar.
• I know the inverse link can break, especially in stress.
• I check the calendar for US data before trading gold.

Frequently asked questions

Do gold and the dollar always move in opposite directions?

No. They often do, but both can rise together during market stress, and gold specific factors such as central bank buying can break the pattern.

Which currency has the biggest weight in the dollar index?

The euro, at roughly 57.6%. A move in EUR/USD alone can therefore move the index significantly.

Why do real yields matter for gold?

Gold pays no interest. When inflation adjusted bond yields are high, holding gold means giving up a meaningful return, so gold tends to struggle; when real yields are low, that cost shrinks.

Related reads