Position size calculator
A free position size calculator for forex, gold, stocks and crypto: enter your account, the share of it you will risk and your stop-loss, and it gives the lots, shares or coins to trade.
Position size
0.20 lots
20,000 units of EUR
At the stop one lot loses 50 pips × $10.00 = $500.00. $100.00 ÷ $500.00 = 0.2000 lots, rounded down to 0.20.
Losing streak check
What a run of stops would cost
Each bar is the share of the balance lost if that many trades in a row hit their stop; the full width is the whole account. Spreads and commissions come on top. Runs like these happen: in our martingale test, buying EUR/USD in 2,947 back-to-back trades since 1999 met a run of 13 losses in a row.
How to calculate position size
Position size follows from three things you decide before the trade: how much of the account you are willing to lose, where the stop-loss goes, and what one unit loses when the price reaches that stop. The formula is size = money at risk ÷ loss per unit at the stop. This position size calculator does that sum, converts it into your account's currency, and rounds the answer down so the risk never ends up above your limit.
Forex. A $10,000 account risking 1% has $100 at risk. On EUR/USD a pip is 0.0001, and one standard lot (100,000 euros) gains or loses $10 a pip. A 50-pip stop therefore costs $500 a lot, and $100 ÷ $500 = 0.20 lots, or 20,000 euros.
A yen pair. On USD/JPY a pip is 0.01, so one lot moves ¥1,000 a pip. At a price of 150.00 that is $6.67. A 30-pip stop costs $200 a lot, so the same $100 buys 0.50 lots.
Gold. Buy gold at $4,000 an ounce with a stop at $3,980 and each ounce loses $20 at the stop. With 100 ounces to a lot, one lot loses $2,000, so $100 ÷ $2,000 = 0.05 lots: 5 ounces, worth $20,000, or twice the account.
Stocks and crypto. Buy a share at $50.00 with a stop at $47.50 and each share loses $2.50: $100 ÷ $2.50 = 40 shares, a $2,000 position. A coin bought at $80,000 with a stop at $76,000 loses $4,000 a coin: $100 buys 0.025 coins.
What a lot and a pip are
A standard lot is 100,000 units of the first currency in the pair; a mini lot is 10,000 (0.10 lots) and a micro lot 1,000 (0.01 lots), the smallest size most brokers take. A pip is the fourth decimal of the price, or the second on pairs quoted in yen. When the US dollar is the second currency, as in EUR/USD or GBP/USD, a pip on one lot is always worth $10. For every other pair the value changes with the exchange rate, which is why the calculator asks for a price.
How much to risk per trade
The common rule of thumb is 1% to 2% of the account per trade. The reason is the losing streak. If every trade risks a fixed share of what is left, a run of stops costs this much:
| Risk | 5 in a row | 10 in a row | 20 in a row |
|---|---|---|---|
| 1% a trade | −4.9% | −9.6% | −18.2% |
| 2% a trade | −9.6% | −18.3% | −33.2% |
| 5% a trade | −22.6% | −40.1% | −64.2% |
At 1% a trade, even 20 losses in a row leave more than four fifths of the account. At 5% a trade, ten losses take two fifths of it, and the gain needed to win that back is far larger than the loss (our compound interest calculator has the table).
Leverage changes the margin, not the risk
The money you lose at the stop depends on the size of the position and the distance to the stop, nothing else. Leverage only decides how much of your own money the broker sets aside as margin while the trade is open. The calculator shows the position's full value next to the balance, so you can see how much leverage the size needs. In the European Union and the UK, retail clients may use at most 30:1 on major currency pairs, 20:1 on other pairs and on gold, and 5:1 on single shares.
Questions people ask
How do you calculate position size based on risk?
Decide the money at risk first (for example 1% of the account), then divide it by what one unit loses at your stop-loss. With $100 at risk and a share that loses $2.50 at the stop, the size is 40 shares.
What is the formula to calculate lot size in forex?
Lots = money at risk ÷ (stop-loss in pips × the value of one pip on one lot). On EUR/USD a pip on one lot is $10, so $100 at risk with a 50-pip stop gives 0.20 lots.
How much lot size should I use?
No lot size is right for everyone: it follows from the account, the risk and the stop. A $1,000 account risking 1% has $10 at risk; with a 20-pip stop on EUR/USD that is $10 ÷ (20 × $10) = 0.05 lots. A wider stop means a smaller size for the same risk.
How do you calculate position size for gold (XAUUSD)?
Measure the stop in dollars an ounce and multiply by the ounces in one lot, which is 100 at most brokers. A $20 stop on 100 ounces loses $2,000 a lot, so $100 at risk gives 0.05 lots. Check your broker's contract size: some use 10 ounces or 1 ounce a lot, and the calculator lets you choose.
Does leverage change the position size?
No. The size comes from the money at risk and the stop. Leverage only changes the margin the broker holds, and high leverage makes it easy to take a position far bigger than the risk you planned.
This calculator shows arithmetic, not advice. Currency prices are filled in from the European Central Bank's euro reference rates of 16 Oct 2026 (Source: ECB); the pairs without the euro are computed from them. Gold, share and coin prices are examples: type your own. The real loss at a stop can be larger than planned when the price gaps past it, and spreads and commissions come on top.