The short version
- A currency pair is a price: how much of the second currency buys one unit of the first.
- Prices move in pips, and positions are sized in lots, so small moves can mean large sums.
- Most retail forex is leveraged; caps exist because leverage is where accounts are usually lost.
Understanding how forex trading works starts with one idea: every trade is two trades at once. When you buy one currency you are selling another. The foreign exchange market is where banks, companies, governments and individuals swap currencies, whether to pay for imports, fund an overseas investment or speculate on the next move in a rate. For a stock investor the topic matters too, because anyone owning foreign shares is quietly exposed to currency changes.
Reading a currency pair
Currencies are quoted in pairs. In EUR/USD 1.0850, the euro is the base currency and the US dollar is the quote currency; one euro costs 1.0850 dollars. If the number rises to 1.0900, the euro has strengthened against the dollar. If it falls to 1.0800, the dollar has strengthened.
A broker shows two prices. The lower one, the bid, is what you receive if you sell. The higher one, the ask, is what you pay if you buy. The difference is the spread, and it is the first cost you pay on every position.
Majors, minors and exotics
- Majors pair the US dollar with another heavily traded currency, such as EUR/USD, USD/JPY or GBP/USD. They usually have the tightest spreads.
- Minors or crosses leave the dollar out, for example EUR/GBP or AUD/JPY.
- Exotics pair a major currency with that of a smaller or emerging economy. Spreads are wider and moves can be abrupt.
Pips, lots and what a move is worth
Exchange rates change in small steps. A pip is 0.0001 for most pairs and 0.01 for pairs quoted in Japanese yen. A move in EUR/USD from 1.0850 to 1.0875 is 25 pips.
Trade size is measured in lots. A standard lot is 100,000 units of the base currency, a mini lot 10,000 and a micro lot 1,000. For any pair where the US dollar is the quote currency, one pip on one standard lot is worth $10.
Illustrative example. You buy 0.3 lots of EUR/USD, which is 30,000 euros. Each pip is worth $3. If you set a stop-loss 20 pips below your entry, the loss if it triggers is about 20 × $3 = $60, plus costs. The pip calculator does this for any pair, including crosses.
Leverage and margin
Because currencies move so little day to day, retail forex is almost always traded with leverage: you put down a deposit, called margin, and control a much larger position. In the UK, EU and Australia retail clients are capped at 30:1 on major pairs and 20:1 on others; in the US the limits are 50:1 on majors and 20:1 on other pairs.
At 30:1, one standard lot of EUR/USD at 1.0850 (a position worth $108,500) needs margin of about $3,616.67. A 1% move against that position costs about $1,085, which is almost a third of the margin. That is the uncomfortable arithmetic behind the warnings. If losses drag your account's margin level down to 50%, a UK or EU broker must start closing positions. Check any trade in the margin calculator first.
When the market is open
Forex has no single exchange, so it follows the business day around the world: from Sunday 17:00 to Friday 17:00 New York time. Activity rises when major financial centres overlap, particularly when London and New York are both open. Spreads usually widen in quiet hours, around the daily rollover at 17:00 New York time and before major announcements.
Positions held past the rollover are charged or credited a swap based on the interest-rate difference between the two currencies. Many brokers apply three days' swap on Wednesday night to cover the weekend.
What moves exchange rates
- Interest rates and central bank guidance. Expectations of higher rates tend to attract capital to a currency.
- Inflation, jobs and growth data, released on published calendars and often followed by sharp, short moves.
- Trade flows and commodity prices, which matter especially for currencies of commodity-exporting countries.
- Risk appetite. In stressed markets money tends to move towards currencies seen as safe havens.
Testing an idea before risking money
Many traders test a strategy against historical prices before using it. Forex backtesting software replays past price data and records what a set of rules would have done: where it would have entered, exited and how much it would have made or lost. Some trading platforms, such as MetaTrader, include a built-in strategy tester.
Backtests are useful for rejecting bad ideas, but they flatter good-looking ones. Common traps include ignoring spreads and swaps, testing on too short a period, and tweaking rules until they fit the past perfectly (known as overfitting). A strategy that only works on the data it was designed on will usually disappoint in live markets. A sensible sequence is: backtest, then test on a separate period you did not use for design, then trade a demo account, and only then consider small real positions. Our guide to choosing a forex strategy goes further.
Why stock investors should care about currencies
You do not need to trade forex for exchange rates to affect you. If your home currency is the pound, euro or yen and you own US shares or a US index fund, your return in your own currency is the share return combined with the change in the dollar. Suppose, as an illustration, a US fund rises 8% over a year while the dollar falls 5% against your currency. In your currency the result is 1.08 × 0.95 = 1.026, a gain of about 2.6% rather than 8%. The reverse can happen too: a weakening home currency flatters overseas returns.
Some funds offer "hedged" share classes that use currency contracts, such as forex futures or forwards, to reduce this effect, usually at a small extra cost. Neither hedged nor unhedged is automatically better; they simply expose you to different risks.
Mistakes beginners make most often
- Trading too large. Choosing a lot size because it feels meaningful, rather than because the potential loss fits the account.
- Moving the stop-loss. Widening a stop as the price approaches it turns a planned small loss into an unplanned large one.
- Ignoring costs. Spreads, commissions and swaps are small per trade but add up quickly for frequent traders.
- Trading news without a plan. Spreads can widen sharply and prices can jump past orders in the seconds around a major release.
- Believing a short winning streak. A few good weeks say very little about whether a method works over years.
Controlling risk
The single most useful habit is to decide how much you are prepared to lose on a trade before placing it, then size the position to match. If your account is $5,000 and you risk 1% per trade, your maximum loss is $50. With a 20-pip stop on a USD-quoted pair, that allows 0.25 lots. The position size calculator works this out for you.
Other habits that help: avoid trading right through major announcements until you understand the risk, keep a written journal of every trade, and never add to a losing position simply to "average down".
Reader questions
Can I learn forex without risking money?
Yes. Most platforms offer demo accounts with virtual money, and backtesting tools let you study historical prices. Remember that demo fills and emotions differ from live trading.
What is the minimum amount needed to trade forex?
Brokers set their own minimums, and micro lots allow small positions. The more important question is how much you can afford to lose, since leverage makes losses arrive quickly.
Is forex trading the same as investing?
Not usually. Retail forex is short-term speculation on price changes with leverage, while investing in shares or funds means owning assets for the long term.
Sources
- European Securities and Markets Authority, CFD product intervention measures
- US Commodity Futures Trading Commission and National Futures Association, retail forex leverage limits
- Australian Securities and Investments Commission, CFD product intervention order