A currency quote looks trivial until you try to say precisely what it means. EUR/USD at 1.0850 — which currency costs what? Get this backwards and every subsequent piece of analysis inherits the error, so it is worth ten minutes now.
Base and quote
Every pair has two sides, written as BASE/QUOTE.
- The base is the first currency. It is always the unit being priced.
- The quote is the second currency. It is what you pay in.
So EUR/USD at 1.0850 reads: one euro costs 1.0850 US dollars. The base is always one unit. The number is always how much quote currency that one unit is worth.
From that single rule everything else follows. If EUR/USD rises to 1.0900, a euro now costs more dollars — the euro strengthened, or the dollar weakened, or both. If it falls to 1.0800, the reverse. The chart of a pair is the chart of the base currency, priced in the quote.
This catches people on USD/JPY. At 150.00, one dollar costs 150 yen. When USD/JPY rises, the dollar is strengthening and the yen is weakening — the yen chart is going up while the yen itself is going down. Traders misread this constantly, especially when translating a "yen strength" headline into a position.
Two prices, not one
Your platform shows two numbers for every pair:
- Bid — the price at which you can sell the base currency.
- Ask (or offer) — the price at which you can buy it.
The ask is always higher than the bid. The difference between them is the spread, and it is the most common way a broker gets paid.
The consequence is that every position starts underwater. Buy at the ask, and you can only close at the bid — so a trade opened at a 1-pip spread begins one pip in the red and must move a pip in your favour just to break even. Nothing has gone wrong; that is the toll for entering.
Spreads are not constant. They tighten when liquidity is deep — the London/New York overlap on a major pair — and widen when it is thin, such as the hours around the Asian open, or the seconds surrounding a major data release. A strategy that is profitable on a 0.8-pip spread can be a loser on 3 pips, which is why spread behaviour deserves attention before a strategy does.
Majors, crosses, exotics
Pairs fall into three practical buckets:
- Majors — pairs containing the US dollar: EUR/USD, USD/JPY, GBP/USD, USD/CHF, AUD/USD, USD/CAD, NZD/USD. These carry the deepest liquidity and the tightest spreads.
- Crosses — pairs without the dollar, such as EUR/GBP or AUD/JPY. Spreads are wider because the trade is often routed through the dollar behind the scenes.
- Exotics — a major against a smaller economy's currency, like USD/TRY or USD/ZAR. Wide spreads, thinner liquidity, and gaps that can jump straight through a stop.
Beginners are frequently drawn to exotics by their large daily ranges. Those ranges come packaged with costs and gap risk that make them a poor place to learn.
Why the convention is what it is
The ordering is not arbitrary but it is also not perfectly logical — it follows an informal seniority: the euro comes first against everything, sterling outranks most others, and the dollar comes first against the yen, franc and Canadian dollar. There is no rule to derive; the majors are simply worth memorising.
What to take from this
- BASE/QUOTE — one unit of the base costs that many units of the quote.
- A pair's chart is the base currency's chart, priced in the quote currency.
- USD/JPY rising means a stronger dollar and a weaker yen.
- Bid to sell, ask to buy; the gap is the spread and you pay it on entry.
- Spreads widen exactly when you are most likely to be trading — news and thin hours.
Next: pips and lots — how price movement converts into money, and why position size is the number that actually determines your risk.