How Currency Pairs Work
Currencies are always traded in pairs. Here is how to read a quote: base and quote currency, bid, ask, the spread, and what going long or short really means.
You cannot trade a currency on its own. A currency only has a price relative to another currency, so forex is always quoted (and traded) in pairs. Understanding how a pair is written is the single most important piece of literacy in this market.
Base and quote currency
A currency pair looks like this:
EUR/USD = 1.0850
There are two currencies and one number. Read it like a sentence:
- The first currency, EUR, is the base currency.
- The second, USD, is the quote currency (sometimes called the counter currency).
- The number is how many units of the quote currency it takes to buy one unit of the base currency.
So EUR/USD = 1.0850 means one euro is worth 1.0850 US dollars. If the price rises to 1.0900, the euro has strengthened against the dollar. If it falls to 1.0800, the euro has weakened, which is the same thing as the dollar strengthening. Every FX price is relative; one currency rising always means the other is falling.
Reading a real quote: bid, ask, and the spread
On a trading platform you will not see one price. You will see two:
| Price | Meaning | |
|---|---|---|
| Bid | 1.0849 | The price at which you can sell the base currency |
| Ask | 1.0851 | The price at which you can buy the base currency |
The gap between them (here, 0.0002) is the spread. The spread is effectively the cost of entering the trade, and it is how many brokers earn their money. The moment you open a position you are slightly behind: you bought at the ask but could only sell back at the lower bid. The price has to move in your favour by at least the spread before you break even.
Spreads are tighter on heavily-traded pairs and during busy hours, and wider on obscure pairs or in quiet, fast-moving conditions.
Going long and going short
Because a pair always involves two currencies, every trade is simultaneously a bet for one and against the other.
- Going long EUR/USD (buying the pair) means you expect the euro to strengthen relative to the dollar.
- Going short EUR/USD (selling the pair) means you expect the euro to weaken relative to the dollar.
There is nothing exotic about “shorting” in forex. Selling a pair you do not own is structurally identical to buying it; you are always long one currency and short the other. This is why FX traders can act on a falling market as easily as a rising one.
The categories of pairs
Pairs are loosely grouped by how heavily they trade:
- Majors: pairs that include the US dollar against another large, widely-traded currency. EUR/USD, USD/JPY, GBP/USD, USD/CHF, USD/CAD, AUD/USD. These are the most liquid, with the tightest spreads.
- Minors (or crosses): pairs of major currencies that do not include the US dollar, such as EUR/GBP or EUR/JPY. Still liquid, usually with slightly wider spreads.
- Exotics: a major currency paired with the currency of a smaller or emerging economy. These have much wider spreads, thinner liquidity, and can move violently.
| Pair | Informal name | Base / Quote |
|---|---|---|
| EUR/USD | ”Fibre” | Euro / US dollar |
| USD/JPY | ”Ninja” / “Gopher” | US dollar / Japanese yen |
| GBP/USD | ”Cable” | British pound / US dollar |
| USD/CAD | ”Loonie” | US dollar / Canadian dollar |
| AUD/USD | ”Aussie” | Australian dollar / US dollar |
Most beginners are steered toward the majors for good reason: tighter spreads and deeper liquidity mean fewer nasty surprises than the exotics produce.
A note on quoting conventions
There is a convention to which currency comes first, and it is not arbitrary. The euro, by agreement, is almost always the base currency when it appears. The British pound usually comes before the dollar. The US dollar is the base against most others (USD/JPY, USD/CAD) but the quote currency against the euro, pound, and Australian and New Zealand dollars. You do not need to memorise this (your platform shows pairs correctly), but it explains why some pairs “look backwards” at first.
The takeaway
Currencies trade in pairs, quoted as the amount of the quote currency needed to buy one unit of the base currency. Platforms show a bid and an ask, and the spread between them is your cost of entry. Buying a pair (long) bets on the base currency strengthening; selling it (short) bets on the opposite. Get comfortable reading a quote, because every other concept in forex is built on top of it.
Next, it is worth understanding the units a price moves in (pips) and the units you trade in (lots).