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Forex position size calculator
Free lot size calculator for UK traders: enter your balance, risk and stop in pips and get the exact lot size for GBPUSD, EURUSD and other majors.
How the lot size is worked out
Position sizing turns your risk into a lot size. You decide two things before the trade: how much of the account you are willing to lose if you are wrong (the risk, usually 0.25% to 1%), and where the stop loss goes (in pips). The lot size is whatever makes those two match.
Lot size = money at risk ÷ (stop in pips × value of one pip on one lot)
On GBPUSD a pip on one standard lot (100,000 units) is worth 10 US dollars. With a £10,000 account, 1% risk and a 10 pip stop, you risk £100. In pounds a pip on one lot is about £7.58 when GBPUSD is 1.3200, so the lot size is 100 ÷ (10 × 7.58) = about 1.32 lots.
Why the stop comes first
Beginners often pick a lot size they like and then squeeze the stop to fit. That puts the stop where the market is likely to reach it. Put the stop where the idea is proven wrong (on the Asia sweep strategy, beyond the sweep, at most 10 pips), then let the calculator size the trade.
Rounding
Brokers trade in steps of 0.01 lots (a micro lot, 1,000 units). Always round down, so you never risk a little more than you planned. Spread and commission also add a small cost to every trade, so the real loss on a full stop can be slightly more than the figure above.
Questions people ask
What is a good risk per trade?
Most professional and prop firm traders risk between 0.25% and 1% of the account on a single trade. That keeps a normal losing run (eight or ten losses in a row happens) to a drawdown you can recover from.
How much is one lot on GBPUSD?
One standard lot is 100,000 units of the base currency, here pounds. A pip on one standard lot of GBPUSD is worth 10 US dollars. A mini lot (0.1) is 1 dollar a pip and a micro lot (0.01) is 10 cents a pip.
Does this work for a prop firm account?
Yes. Use the funded account size as the balance and the account currency your firm uses. Then check the result against the firm’s daily loss limit with the drawdown calculator.
Tools and terms for this page
Free tools: Pip value calculator
Results are estimates for education only. Your broker’s figures, spreads and commission decide the real numbers.