The US dollar is involved in approximately 88% of all forex transactions according to global central bank surveys compiled by the Bank for International Settlements (BIS). It is the world's primary reserve currency. When the dollar moves, the entire forex market moves. But to understand dollar direction, you need a single reference point that captures the dollar's overall strength or weakness - not just its movement against one specific currency. That reference point is the ICE US Dollar Index (DXY). Every serious forex trader watches the DXY.
What Is the DXY?
The US Dollar Index - ticker DXY - is a weighted geometric average of the value of the US dollar against a basket of six major currencies. It was created in 1973 when the Bretton Woods fixed exchange rate system collapsed, providing a standardised measure of dollar value. A DXY reading of 100 represents the dollar at its 1973 baseline value. Above 100 means the dollar is stronger than its 1973 baseline. Below 100 means it is weaker.
The Six Currencies in the Index
The DXY is not equally weighted across all six currencies. The euro dominates significantly - this is a critical point for understanding how DXY relates to EUR/USD specifically.
EUR - Euro: 57.6% JPY - Japanese Yen: 13.6% GBP - British Pound: 11.9% CAD - Canadian Dollar: 9.1% SEK - Swedish Krona: 4.2% CHF - Swiss Franc: 3.6% Total: 100.0% The euro is more than half the index. This means DXY and EUR/USD have a strong inverse correlation - when DXY rises, EUR/USD almost always falls. When DXY falls, EUR/USD almost always rises.
How to Read DXY Price Action
DXY is traded as a futures contract on the Intercontinental Exchange (ICE) and has its own price chart - candlestick charts, moving averages, support and resistance levels. You apply the same technical analysis to DXY that you apply to currency pairs.
DXY at 106.50 and rising: Dollar is strong across the basket. EUR/USD likely falling. GBP/USD likely falling. USD/JPY likely rising. DXY at 102.00 and falling: Dollar is weakening across the basket. EUR/USD likely rising. GBP/USD likely rising. USD/JPY likely falling.
DXY and USD Pairs
For pairs where USD is the quote currency (EUR/USD, GBP/USD, AUD/USD, NZD/USD): DXY rising = pair falling. DXY falling = pair rising.
For pairs where USD is the base currency (USD/JPY, USD/CHF, USD/CAD): DXY rising = pair rising. DXY falling = pair falling.
Using DXY as a Sentiment Filter
The most practical use of DXY for retail traders is as a sentiment filter - a broader context check before entering any USD pair trade. If you are looking at a bullish setup on EUR/USD but DXY is approaching major support on the daily chart - which would imply dollar strengthening - the sentiment environment for that EUR/USD long is less favourable than if DXY were approaching resistance.
Always check DXY before entering any USD pair. Is the dollar in an uptrend, downtrend, or range? Is DXY at support or resistance? This 30-second check adds a layer of context that no individual pair chart can provide.