Dollar Index (DXY): Six Currencies, One Fixed Formula, Rebuilt From the Quotes
The dollar index, usually quoted as DXY, is ICE's measure of the US dollar against a fixed basket of six currencies, with the euro making up 57.6% of the weight. It closed at 101.035 on 25 Sep 2026, and a reading below 100 means the dollar is weaker against that basket than in March 1973.
Headlines treat the dollar index as the price of the dollar. It is narrower than that: a fixed recipe of six exchange rates, set decades ago and changed once since. Knowing the recipe tells you what a DXY move can and cannot mean, and the recipe is short enough to recompute by hand, which this page does with Friday’s closing quotes.
How it works
The index compares the dollar with six currencies at once. ICE Futures U.S. lists them as the euro, Japanese yen, British pound, Canadian dollar, Swedish krona and Swiss franc.
It is a weighted geometric average, not a simple one. Each exchange rate is raised to a power set by its weight, the results are multiplied together, and a fixed constant scales the answer. ICE’s FAQ prints the formula in full: 50.14348112 times EUR/USD to the power -0.576, times USD/JPY to the power 0.136, times GBP/USD to the power -0.119, times USD/CAD to the power 0.091, times USD/SEK to the power 0.042, times USD/CHF to the power 0.036.
The signs follow the quote. Where the dollar is the second currency in the pair, as in EUR/USD, the power is negative: a higher euro price means a weaker dollar, so it pulls the index down. Where the dollar comes first, as in USD/JPY, a higher quote means a stronger dollar and lifts the index.
The reference point is March 1973. ICE’s own page reads a 2020 close of 93.15 as a sign that the dollar had lost value against the basket since the index began in March 1973. A reading above 100 is the other way round.
It trades as a futures contract. Futures on the index were listed on 20 Nov 1985, according to ICE’s FAQ, and one contract is worth $1,000 times the index value. DXY itself is a data-vendor ticker; ICE’s exchange symbol is DX.
Six currencies, one fixed recipe
The weights, as ICE publishes them:
| Currency | Pair used | Weight |
|---|---|---|
| Euro | EUR/USD | 57.6% |
| Japanese yen | USD/JPY | 13.6% |
| British pound | GBP/USD | 11.9% |
| Canadian dollar | USD/CAD | 9.1% |
| Swedish krona | USD/SEK | 4.2% |
| Swiss franc | USD/CHF | 3.6% |
They do not rebalance. ICE’s FAQ says there are no regularly scheduled adjustments. The basket changed once, in January 1999, when the euro replaced the German mark, French franc, Italian lira, Dutch guilder and Belgian franc. ICE kept the combined weight of those five at 57.6%.
So the index still reflects the trade pattern of an earlier era. Nothing in the recipe tracks where the US trades today, which is why the Federal Reserve publishes its own index built on current trade.
A worked example
Rebuild Friday’s close from the six quotes. These are the last quotes Yahoo Finance recorded on Friday 25 Sep 2026, stamped between 20:59 and 22:59 UTC:
- EUR/USD 1.1392, raised to -0.576
- USD/JPY 157.185, raised to 0.136
- GBP/USD 1.3246, raised to -0.119
- USD/CAD 1.4139, raised to 0.091
- USD/SEK 9.9145, raised to 0.042
- USD/CHF 0.8283, raised to 0.036
Multiply the six results by 50.14348112 and the answer is 101.014. The index itself, DX-Y.NYB on Yahoo Finance, last traded at 101.035. The gap is 0.021 points, about 0.02%. The six quotes were stamped at different moments, up to two hours apart, so an exact match is not expected.
Now move one pair at a time. A 1% rise in EUR/USD, with the other five unchanged, multiplies the index by 1.01 to the power -0.576, which is 0.99429: a fall of 0.571%. A 1% rise in USD/JPY lifts the index by 0.135%. A 1% rise in USD/CHF lifts it by 0.036%. The euro moves DXY about four times as much as the yen and about sixteen times as much as the franc.
2025 shows what that means in practice. From the first session of 2025 to the last, EUR/USD rose 13.5%, from 1.0352 to 1.1747. On its own, that move would take 7.0% off the index. DXY fell 10.2% over the same sessions, from 109.39 to 98.28, so the euro accounts for most of the year’s fall.
A different dollar index: the Fed’s broad measure
The Federal Reserve’s nominal broad dollar index is built differently. It is published in the Fed’s H.10 release, set so that January 2006 equals 100, and weighted by trade with 26 economies. The Fed updates the weights; its page says the previous set was in use until 30 Jan 2026, and the current set is the 2026 column of its table.
In that table the euro area weighs 21.0%, Mexico 14.8%, Canada 12.8% and China 10.9%. The six DXY currencies together make up 47.8% of the Fed’s index. Mexico and China, which DXY does not include at all, carry 25.7% between them.
The two indexes can disagree about the same year. From 31 Dec 2024 to 31 Dec 2025, DXY fell 9.4% and the Fed’s broad index fell 7.4%. From the end of 2025 to 18 Sep 2026, the latest Fed figure available on 25 Sep, DXY rose 2.0% while the broad index slipped 0.2%. Against the basket DXY measures, the dollar was stronger this year; against the wider set of trading partners, it was roughly flat.
The original data
The first set is the two weight tables side by side. ICE’s six fixed weights, read from its FAQ on 25 Sep 2026, against the Federal Reserve’s 2026 trade weights for the same currencies plus the two largest that DXY leaves out. The rows are in a CSV of DXY and Fed broad index weights, and the six-quote rebuild above is in a CSV of the formula check.
The largest difference is the euro. It is 57.6% of DXY and 21.0% of the Fed’s measure, so a euro move counts almost three times as heavily in the index traders quote. The Swedish krona is the most overweighted in relative terms: 4.2% of DXY against 0.6% of the Fed’s index, nearly seven times as much. The Canadian dollar is the only one of the six that the Fed weighs more heavily than ICE does, 12.8% against 9.1%. The Fed gives the yen and the pound 5.2% each and the Swiss franc 3.0%. For a trader, the practical point is simple: DXY is mostly a euro chart read upside down, with the yen and the pound as the next voices.
The second set is the index’s own history. Yahoo Finance carries DX-Y.NYB daily from 4 Jan 1971, which is earlier than the March 1973 reference month. Across that record the highest close was 164.72 on 25 Feb 1985 and the lowest 71.33 on 22 Apr 2008. ICE’s page gives a low of 70.698 in March 2008, a different reading from the daily closes Yahoo stores, so quote the source with the number. The month-end closes are in a CSV of dollar index month-end closes.
Recent years in the same file: the index ended 2024 at 108.49 and 2025 at 98.28, a fall of 9.4%. By 25 Sep 2026 it was at 101.035, up 2.8% for the year. Over more than five decades it has spent long spells both above and below 100, so a level on its own says little about direction.
When it fails
As a measure of the dollar against the world. With no Mexican peso, no Chinese yuan and no emerging-market currency in the basket, DXY can rise while the dollar weakens against the partners the US trades with most. The 2026 figures above show exactly that divergence.
As an independent signal beside EUR/USD. A trader who watches both is watching mostly the same thing twice. Confirmation from DXY adds little to a euro trade.
Around yen-driven moves. A sharp yen move shifts DXY by less than a quarter of the same move in the euro, so a yen crisis can look mild on the index.
On fixed-weight assumptions. Nothing in the formula updates when trade patterns change. The weights are a historical choice that ICE has kept since 1999, not a current estimate of anything.
When a futures chart is read as the index. DX futures reflect interest-rate differences between the dollar and the six currencies, according to ICE’s FAQ, so a futures chart and the spot index differ, by an amount that shrinks as each contract nears expiry.
Related
A currency pair is the building block of every figure in the formula, and USD/JPY covers the second-largest piece of it. The gold trading page explains why traders glance at a dollar measure before a gold trade, and currency risk covers what a dollar move does to holdings priced in other currencies.
When the dollar index moves, I check EUR/USD before I read anything into it. More than half the index is the euro, so a DXY move that the euro does not share is usually a yen or pound story, not a broad dollar one.
— Michael Whitman
This page is educational, not financial advice. Test every idea on your own charts before risking money.