Risk a precise amount of your account on every trade. Pick your pair, enter your balance, the percentage you're willing to risk, and your stop loss in pips. The calculator returns the lot size that keeps your dollar risk exactly where you want it.
Position sizing answers one question: how many lots can I trade without risking more than I've decided to risk? The calculator first converts your risk percentage into a dollar amount — account balance multiplied by risk percent. It then works out what one pip is worth on the pair you selected, in your account currency, for one standard lot.
Dividing your dollar risk by (stop loss in pips × pip value per lot) gives the lot size that makes your stop loss equal exactly the dollar amount you chose to risk — no more, no less. This is the core position sizing formula used by risk-managed traders and prop firms: Lot Size = (Account Balance × Risk %) ÷ (Stop Loss in Pips × Pip Value per Lot).
Because pip value depends on the pair's quote currency and your account currency, the same stop distance and the same dollar risk can produce very different lot sizes on EUR/USD versus USD/JPY — the calculator handles that conversion for you automatically.
Worked example: with a $10,000 account, a 1% risk tolerance, and a 25-pip stop loss on EUR/USD — where one pip on a standard lot is worth $10 — your dollar risk is $10,000 × 1% = $100. Dividing that by (25 pips × $10) gives a position size of 0.4 lots. If your stop is hit, you lose exactly $100; if it isn't, you're free to let the trade run toward your target without second-guessing the size.
Position size is how many units, mini lots, or standard lots you trade on a single position. It's the lever that connects your stop loss distance to your dollar risk — the same stop in pips can mean very different dollar risk depending on how large your position is.
Multiply your account balance by the percentage you're risking to get your dollar risk. Divide that by your stop loss in pips multiplied by the pip value per lot for the pair you're trading. The result is the lot size that keeps your loss capped at the dollar amount you chose.
Most traders who survive long-term risk between 0.5% and 2% of their account per trade. Risking more than that means a short losing streak — which is statistically normal — can do serious damage to your account.
A standard lot is 100,000 units of the base currency, a mini lot is 10,000 units (one-tenth), and a micro lot is 1,000 units (one-hundredth). Smaller lot sizes let you fine-tune position size and risk more precisely, especially on smaller accounts.
Pip value differs by pair because it depends on the pair's quote currency and the current exchange rate back to your account currency. The calculator re-prices pip value for whichever pair you select, so the same dollar risk can translate into a different lot size on a different pair.
No — this tool sizes your position based on risk (how much you could lose if your stop is hit), not on how much margin your broker requires to open it. Use the Margin Calculator alongside this one to confirm your account has enough free margin for the resulting position size.