Forex Position Size & Lot Size Calculator
Trade the same risk every time. Enter your balance, risk %, stop-loss in pips and pip value, and get the exact number of standard, mini and micro lots to place — for any account currency, anywhere in the world.
A standard lot is 100,000 units. For USD-quoted pairs (e.g. EUR/USD) one pip on a standard lot is worth about $10, so 10 is the default. Advanced users: override this with the pip value for your pair and account currency (find it with our pip calculator).
Your position size
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How the lot size is calculated
- Your risk amount = account balance × risk % — the most you'll lose if the stop is hit.
- Your risk per lot = stop-loss in pips × pip value per standard lot.
- Your position size = risk amount ÷ risk per lot, expressed in standard lots.
- Multiply by 10 for mini lots, by 100 for micro lots, and by 100,000 for the number of units.
A worked example
Say you have a $10,000 account and risk 1% per trade — that's $100 at risk. Your stop-loss is 20 pips away, and on a USD-quoted pair a standard lot is worth about $10 per pip. Risk per lot is 20 × $10 = $200, so your size is $100 ÷ $200 = 0.5 standard lots — the same as 5 mini lots, 50 micro lots, or 50,000 units. If the stop is hit, you lose about $100, exactly the 1% you planned.
Change any input and the size updates. Widen the stop and the size shrinks to keep your risk fixed; tighten it and the size grows. That is the whole point of position sizing — the market decides the stop, and your sizing keeps the loss constant. Always round down to a size your broker supports so you never exceed your planned risk.
Frequently asked questions
How do you calculate forex lot size from risk?
First find the money you'll risk: account balance × risk %. Then divide that by (stop-loss in pips × pip value per standard lot). The result is your position size in standard lots. Example: a $10,000 account risking 1% ($100) with a 20-pip stop and $10 per pip per lot gives 100 ÷ (20 × 10) = 0.5 standard lots.
What is a standard, mini and micro lot?
A standard lot is 100,000 units of the base currency, a mini lot is 10,000 units (0.1 standard), and a micro lot is 1,000 units (0.01 standard). Pip value scales with size — on a USD-quoted pair a standard lot is about $10 per pip, a mini lot about $1, and a micro lot about $0.10. This calculator shows all three so you can pick the size your broker allows.
What pip value should I enter?
For pairs quoted in US dollars (like EUR/USD or GBP/USD), one pip on a standard lot is worth about $10, so the default of 10 works for a USD account. If your pair's quote currency differs from your account currency, or you trade JPY pairs, the pip value changes — enter your pair's actual pip value per standard lot. Our forex pip calculator works it out for you.
Why size positions by risk instead of a fixed lot size?
Fixing your lot size means a wide stop risks far more than a tight stop, so your losses swing wildly. Sizing by a fixed percentage of your account keeps every losing trade roughly the same small size, no matter the stop distance. That consistency is what protects your capital through a losing streak.
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Educational tool only — not financial advice, and no promise of any return. Trading forex on margin involves substantial risk of loss. See more free tools.