How to calculate position size in forex

The position size formula, step by step

Position size is the number of lots you trade. It is the setting that turns a stop loss measured in pips into a loss measured in money, which is why many traders calculate it before every trade instead of using the same size each time.

The calculation needs three inputs and takes seconds.

• Money at risk — the balance multiplied by the percentage you are willing to lose if the stop is hit.
• Stop loss in pips — the distance from your entry to the price where the trade idea is proven wrong.
• Pip value per lot — on pairs quoted in US dollars, such as EUR/USD or GBP/USD, one pip on a standard lot is $10 on a USD account.

Check it backwards: 0.20 lots is $2 per pip, and 25 pips × $2 = $50, the amount decided at the start. If pips and lots are new to you, our guide to what forex is explains them first.

Position size calculator

Enter your balance, the risk per trade and the stop distance. The calculator returns the lot size, rounded down to 0.01, and the money that size actually puts at risk.

The result shown by default is for $5,000, 1% risk, a 25-pip stop and $10 per pip on a standard lot: 0.20 lots and $50 at risk. Lots are rounded down, never up, so the loss planned at the stop stays within your limit; spread, commission and slippage come on top.

The result is only as good as the stop distance. A stop placed to fit a size, instead of where the chart says the idea fails, defeats the whole calculation. The steps in chapter 06 put the two in the right order.

How much to risk per trade

There is no correct percentage, but there is a common range: many traders risk 1–2% of the account per trade, and some less while they are learning. The reason is not caution for its own sake. It is the way losing streaks compound.

Even a sound strategy strings losses together, and a run of ten is quite possible over a few hundred trades, especially at lower win rates. This is what ten consecutive losses do when each one risks the same percentage of the current balance:

To get back to the starting balance, a 9.6% drawdown (a fall from the starting balance) needs a 10.6% gain, an 18.3% drawdown needs 22.4%, and a 40.1% drawdown needs 67.0%.

That asymmetry is the point. Losses are recovered from a smaller base, so deep drawdowns take disproportionate gains to undo. Keeping each loss small keeps the arithmetic on your side.

Risk per trade on an account with a drawdown limit

Some accounts come with a hard loss limit. On Hero10X, the only rule is a 10% static drawdown, so the size of each trade decides how many losses fit before that line is reached. The formula is the same; only the budget changes.

Pip value: what one pip is worth

Pip value depends on two things: the lot size and the currency the pair is quoted in. The first is simple: a standard lot is 100,000 units, and each step down in lot size divides the pip value by ten.

The second is where many calculations go wrong. On pairs quoted in US dollars, a pip on one standard lot is always $10 on a USD account. On other pairs, a pip is worth 10 units of the quote currency (1,000 yen on JPY pairs), converted into dollars at the current rate:

Example rates, for illustration only. The contract specification in your trading platform gives the exact figure for each symbol.

It matters more than it looks. The same $50 risk with a 20-pip stop is 0.25 lots on EUR/USD but 0.37 lots on USD/JPY at 150.00, because each pip is worth less. Using $10 for every pair would make a USD/CHF position 25% larger than planned.

The calculator above assumes a USD account; on an account in another currency, the pip value is converted into that currency. Gold, indices and crypto have their own contract sizes, so their value per point comes from the contract specification. The full list of markets shows what is available; the formula does not change.

How many lots should I trade? Three worked examples

Here is the same formula applied to three account sizes, all on EUR/USD at $10 per pip per standard lot. The stops differ because in practice they come from the chart, not from the account size.

Lots = money at risk ÷ (stop in pips × $10), rounded down to 0.01.

$1,000 account at 1%

$1,000 × 1% = $10. With a 20-pip stop: $10 ÷ (20 × $10) = 0.05 lots, or $0.50 per pip. Twenty pips against the trade cost exactly $10.

$5,000 account at 2%

$5,000 × 2% = $100. With a 30-pip stop: $100 ÷ 300 = 0.333 lots, rounded down to 0.33. The loss at the stop is 0.33 × 30 × $10 = $99, just under the limit.

$25,000 account at 1%

$25,000 × 1% = $250. A wider 40-pip stop gives $250 ÷ 400 = 0.625 lots, rounded down to 0.62, for $248 at risk. A wider stop means a smaller position, not a bigger loss.

When the result is below 0.01 lots

Small accounts reach the floor quickly. $200 at 1% is $2; with a 30-pip stop the formula gives 0.0067 lots, below the 0.01-lot minimum most platforms use. At 0.01 lots, that trade would risk $3, or 1.5% of the account. Traders in that position usually wait for a setup with a tighter stop the chart genuinely supports, accept the higher percentage knowingly or skip the trade.

Stop loss first, lot size second

The order of the steps is what makes position sizing work. The chart sets the stop, the risk budget sets the money and the lot size is simply the result.

1. 1Find the stopWhere the trade idea is wrong, in pips.
2. 2Set the riskA fixed % of the current balance.
3. 3Calculate lotsRounded down to 0.01.
4. 4Place the orderSize and stop entered together.

On TradeLocker and MetaTrader 5, the lot size and the stop loss go into the same order ticket, so both can be checked before the trade is sent.

Where leverage fits in

Leverage does not change the risk of a correctly sized trade; it changes the margin the trade ties up. 0.20 lots of EUR/USD at 1.0850 is $21,700 of currency. At 1:100 that needs $217 of margin, and at 1:30 about $723. Either way, the loss at a 25-pip stop is $50. The guide to leverage and margin covers the difference in detail.

Mistakes that break the calculation

• Moving the stop to fit the size — the stop belongs where the chart says; the size adapts to it.
• Using $10 per pip on every pair — only pairs quoted in US dollars are worth $10; USD/JPY, USD/CHF, USD/CAD and crosses such as EUR/GBP are not.
• Rounding up — 0.625 lots becomes 0.62, not 0.63.
• Forgetting costs — spread, commission and slippage on fast news can make the real loss larger than planned. Your account type decides how those costs are charged.
• Ignoring the reward side — size fixes what a loss costs; the risk-reward ratio decides whether the wins pay for it.