Free tool
Position size calculator
Work out how many lots to trade from your account balance, the percentage you are willing to risk, and where your stop sits. The arithmetic is shown in full.
- Money at risk
- $100.00
- Loss per 1.00 lot
- $200.00
- Units
- 50000
- Exact (unrounded)
- 0.5000 lots
Rounded down to 0.01 lots — rounding up would risk more than the 1% you asked for. Excludes spread, commission and swap.
How the calculation works
Position sizing answers one question: how large can this trade be so that being wrong costs a known, chosen amount? Three numbers decide it — what the account holds, what fraction of it you are prepared to lose on one idea, and how far the price has to travel against you before you accept the idea was wrong.
risk amount = balance × risk % loss per lot = stop distance (in price) × contract size position = risk amount ÷ loss per lot
Working in price distance rather than pips is what keeps this to a single formula. A gold stop of “$5” and a EURUSD stop of “20 pips” are the same kind of quantity once both are written as a price move, and instruments then differ only by contract size. The calculator converts pips to price for you.
A worked example
A $10,000 account, risking 2% per trade, entering EURUSD with a 20-pip stop. One standard lot of EURUSD is 100,000 units, and one pip is 0.0001.
risk amount = 10,000 × 2% = $200 stop (price) = 20 × 0.0001 = 0.0020 loss per lot = 0.0020 × 100,000 = $200 position = 200 ÷ 200 = 1.00 lot
Widen the stop to 40 pips and the position halves to 0.50 lots. The risk stays $200 — that is the point. Sizing is what keeps a wider stop from becoming a bigger loss.
Assumptions, and where they stop holding
The result is exact when the instrument is quoted in your account currency — a USD account trading EURUSD or XAUUSD, for instance. If you hold a EUR account and trade a USD-quoted instrument, the figure is in the quote currency and needs converting at the rate you actually get. This calculator does not invent an exchange rate for you.
It also excludes spread, commission and swap. Those decide what a trade costs to hold; they do not change what a stop-out costs, which is what sizing is for. And it rounds down to 0.01 lots, never up — rounding up would quietly risk more than the percentage you asked for.
Contract sizes here follow the common retail conventions. Brokers differ, particularly on mini and micro accounts, so confirm yours before sizing a live position.
Sizing one trade versus sizing all of them
A calculator tells you what a single position should be. It cannot tell you whether you actually traded that size, or whether the 2% you intended was 2% on Monday and 6% by Thursday. That only shows up across a whole history — which is what a journal is for.
Frequently asked questions
- How do I calculate position size from a percentage risk?
- Multiply your balance by the percentage you are risking to get the money at risk, then divide that by what one standard lot loses at your stop distance. Loss per lot is the stop distance in price multiplied by the contract size. A $10,000 account risking 2% with a 20-pip EURUSD stop risks $200, loses $200 per lot, and so trades 1.00 lot.
- Should I enter my stop in pips or in price?
- Either. The calculator works in price distance throughout and converts pips to price for you using the pip size of the instrument you pick. Price distance is what makes one formula cover forex, metals and indices — a $5 gold stop and a 20-pip EURUSD stop are the same kind of quantity once both are written as a price move.
- Does the calculator round the lot size up or down?
- Down, to 0.01 lots, never up. Rounding up would risk more than the percentage you asked for, which defeats the purpose of sizing. If the exact answer is 0.478 lots the calculator returns 0.47.
- Does it include spread, commission and swap?
- No. Those decide what a trade costs to hold; they do not change what a stop-out costs, which is what position sizing is for. Budget for them separately.
- What if my account currency is not the quote currency?
- The result is exact when the instrument is quoted in your account currency — a USD account trading EURUSD or XAUUSD, for example. Otherwise the figure is in the quote currency and needs converting at the rate you actually get. The calculator does not invent an exchange rate.
- Is this calculator free, and do I need an account?
- It is free and needs no account, no email and no card. The result is never gated.