Forex is the market for exchanging one currency for another. There is no central exchange — trading happens through a network of banks and brokers, roughly 24 hours a day from Sunday evening to Friday evening. Every trade buys one currency and sells another at the same time, so a forex position is always a bet on a relationship, never on a single thing.
That last point is the one beginners skip, and almost every early misunderstanding traces back to it. You do not "buy the euro". You buy the euro against something, and the trade can go your way because your currency strengthened, because the other one weakened, or because of both at once. Get that straight and the rest of the mechanics fall into place quickly.
How big the market actually is
Trading in over-the-counter foreign exchange markets averaged $9.6 trillion per day in April 2025, a 28% increase on the $7.5 trillion per day recorded three years earlier, and the US dollar was on one side of 89.2% of all trades (BIS Triennial Central Bank Survey, OTC foreign exchange turnover in April 2025). Spot turnover alone rose 42% over the same period.
Two practical consequences follow. First, the major pairs are continuously quoted, cheap to trade and very hard to gap — which is genuinely useful if you are a small account. Second, and less comfortably: you are a rounding error. Nothing you do moves the price, no "smart money" is hunting your specific stop, and any strategy premised on outsmarting a market this deep on information grounds is not a strategy.
What a currency pair actually is
A quote like EUR/USD 1.0850 means one euro costs 1.0850 US dollars. The first currency is the base, the second is the quote. Buying the pair means buying euros with dollars; selling it means the reverse.
- Majors — the seven or so pairs involving the US dollar and another large economy's currency (EUR/USD, USD/JPY, GBP/USD and so on). Tightest spreads, deepest liquidity, most news coverage.
- Minors / crosses — pairs without the US dollar, like EUR/GBP or AUD/JPY. Perfectly tradeable, slightly wider spreads, and each one is effectively two dollar pairs stitched together.
- Exotics — a major against a smaller or emerging-market currency. Wide spreads, sudden gaps, occasional political risk. Not where a new trader should be learning.
Because the dollar appears on nearly nine in ten trades, most pairs move together to some degree. Being long EUR/USD and long GBP/USD is close to being twice as short the dollar — one position, not two. That is correlation risk, and it is the most common way forex traders take four times the exposure they think they have.
Pips, lots and what a move is worth
A pip is the standard smallest quoted increment: 0.0001 for most pairs, 0.01 for yen pairs. A lot is the trade size. Together they convert a chart move into money.
| Lot | Units of base currency | Approx. value per pip* | 50-pip stop costs |
|---|---|---|---|
| Standard | 100,000 | $10.00 | $500 |
| Mini | 10,000 | $1.00 | $50 |
| Micro | 1,000 | $0.10 | $5 |
| Nano | 100 | $0.01 | $0.50 |
*For pairs quoted in US dollars. Pip value differs for other quote currencies and for yen pairs.
Read that table right to left and you have the whole of position sizing. You decide what a loss is allowed to cost, you measure your stop in pips, and the lot size is whatever number makes those two agree. Conviction never enters the calculation. There is a full walkthrough in what a lot size is, and you can run your own numbers with the free lot size and position size calculator.
The four sessions, and why the overlap matters
Twenty-four-hour trading does not mean twenty-four hours of opportunity. Activity follows the working day around the world:
| Session | Approx. hours (ET) | Character |
|---|---|---|
| Sydney | 6:00 p.m. – 3:00 a.m. | Thin. AUD and NZD news lands here. |
| Tokyo | 8:00 p.m. – 5:00 a.m. | Yen pairs active; ranges often set here. |
| London | 3:00 a.m. – 12:00 p.m. | The largest session. Trends frequently start at the London open. |
| New York | 8:00 a.m. – 5:00 p.m. | US data releases; the second half often drifts. |
| London–NY overlap | 8:00 a.m. – 12:00 p.m. | Busiest window: tightest spreads, largest moves. |
Session times shift by an hour when daylight saving changes in one region and not the other, so check them against your own clock rather than memorising them. There is a full breakdown of each session, the overlap and how to trade around a job in forex sessions explained, and the broader point — that when you trade shapes your results as much as what you trade — is covered across markets in the best time of day to trade.
Leverage: the variable that decides survival
Forex brokers offer leverage that is unavailable in most other retail markets, and available leverage varies enormously by jurisdiction — some regulators cap retail leverage at modest multiples for major pairs while others permit far more. Check what applies where you live, because it is a legal question, not a broker preference.
What does not vary is the arithmetic. Leverage does not change your risk on a trade — your stop distance and your lot size do that. What leverage changes is the maximum position your account will permit, and therefore how easy it is to take a position that a normal adverse move would destroy. High leverage is not dangerous because it is powerful; it is dangerous because it removes the constraint that used to stop you sizing badly. The mechanics are laid out in what leverage really is and how a margin call happens.
What actually moves currencies
- Interest rate expectations. The dominant driver. Currencies tend to strengthen when markets expect their central bank to hold rates higher relative to others. Note "expectations" — the move usually happens as the expectation shifts, not when the decision is announced.
- Scheduled economic data. Inflation prints, employment reports, GDP, central bank statements. These are on a published calendar, which means there is no excuse for being surprised by one.
- Risk sentiment. In stressed markets, capital moves toward currencies perceived as safe havens and away from higher-yielding ones, often regardless of each country's own data.
- Positioning and flow. Month-end rebalancing, option expiries and large corporate hedges can push price in ways no fundamental explains. This is usually the real answer when a move "makes no sense".
You do not need a macro thesis to trade forex technically. You do need to know when the big scheduled releases are, because holding a tight stop through one is not a trade, it is a coin flip with worse fill prices.
The three costs that erode an edge
- Spread — the gap between bid and ask. You pay it on entry, every time. On EUR/USD it is typically a fraction of a pip; on an exotic it can be many pips.
- Commission — charged per lot on raw-spread accounts. Often cheaper overall than a "zero commission" account with a marked-up spread; do the arithmetic rather than trusting the label.
- Swap / rollover — the financing debit or credit applied to positions held past the daily rollover, reflecting the interest rate difference between the two currencies. Irrelevant to a scalper, material to anyone holding for days.
A trader taking five trades a day pays the spread roughly 1,250 times a year. That is not a rounding error; on a small account it is frequently the difference between a slight edge and a slow bleed, which is one reason trade frequency deserves more thought than it usually gets. Choosing the venue matters too — see how to choose a broker.
How to start without paying tuition twice
- Pick one pair. EUR/USD or GBP/USD. One pair, one session, for at least a month. Breadth is what beginners reach for when depth gets uncomfortable.
- Fix your risk before your strategy. Decide the percentage of the account a single trade may cost, and let that set every position size. Sizing from risk is the habit that outlasts every setup you will ever learn.
- Write the plan down. Entry condition, invalidation, targets — in advance, in words. A trading plan that lives only in your head is a preference, not a plan.
- Keep records from day one. A journal is how you find out whether your edge is real, and it takes two months of data before it can tell you anything.
If you are still deciding whether forex is the right market at all, the trade-offs against the alternatives are set out in forex vs futures and forex vs stocks. There is no universally correct answer — hours, capital and temperament decide it.
Frequently Asked Questions
How big is the forex market?
Trading in over-the-counter foreign exchange markets averaged $9.6 trillion per day in April 2025, according to the BIS Triennial Central Bank Survey — a 28% increase on the $7.5 trillion per day recorded in April 2022. The US dollar was on one side of 89.2% of all trades. That scale is why major pairs are continuously quoted and cheap to trade, and it is also why no retail participant moves the price.
Is forex open 24 hours a day?
Effectively yes, from Sunday evening to Friday evening, because trading passes between banking centres around the globe rather than through one exchange with an opening bell. It is not uniformly active, though. Liquidity concentrates in the Tokyo, London and New York sessions, and the London–New York overlap is the busiest window of the day. The quiet hours between sessions have wider spreads and thinner moves, which is where a lot of avoidable losses happen.
What is a pip and what is it worth?
A pip is the standard smallest quoted increment for most currency pairs — 0.0001, or the fourth decimal place. For pairs quoted against the Japanese yen it is 0.01, the second decimal place. On a standard lot of 100,000 units of a pair quoted in US dollars, one pip is $10; on a mini lot it is $1, and on a micro lot it is $0.10. Your loss on a trade is simply your stop distance in pips multiplied by that per-pip value.
How much money do you need to start trading forex?
Brokers will open accounts for very small amounts, but the size that matters is the one where a sensible risk per trade is still a meaningful position. Risking 1% of a $500 account is $5, which on a micro lot is a stop of about 50 pips — workable, but it leaves no room for error and makes costs a large share of the outcome. The account size question is really a risk question, and it is answered by working backwards from your stop, not forwards from your ambition.
Bottom line
Forex is a decentralised, near-continuous market of roughly $9.6 trillion a day in which every position is a relationship between two currencies rather than a bet on one. The mechanics that decide your results are unglamorous: pip value and lot size turn a chart move into money, session timing decides whether the market is liquid enough to be worth trading, leverage decides how badly a sizing mistake can hurt, and spread and swap quietly tax every decision. Start with one pair, size from risk, and build from the risk management system outward — then read forex vs futures if you are still choosing a market, and how to start day trading for the wider first-steps map.