Forex lot size calculator (position size)
Updated 2026-09-19
A lot size calculator tells you how many lots to open so that you don't lose more than a fixed percentage of your account if price reaches your stop loss. It is the most important risk management tool: position size, not prediction, decides how much you can lose.
Suggested size: 0.20 lots
Units: 20,000
Amount at risk: 50.00
Value of 1 pip per lot (calculated automatically): 10.00
Backup exchange rates (live data unavailable right now): the result is indicative only.
Educational tool: results are estimates and depend on the values you enter. Not financial advice. Trading involves risk.
The formula
Lots = (balance × risk %) ÷ (stop loss in pips × value of 1 pip per lot). Round the result down to the step allowed by your broker (usually 0.01).
Example
A 5,000 account, 1% risk (50), a 25-pip stop on EUR/USD (1 pip = 10 per standard lot): 50 ÷ (25 × 10) = 0.20 lots, i.e. 2 mini lots.
Pip value
Pick the instrument (including yen pairs and gold) and the calculator uses the site's live quotes to work out the value of 1 pip in dollars by itself: you don't need to enter it. For pairs with the US dollar as the quote currency (EUR/USD, GBP/USD, AUD/USD, NZD/USD) it's always about 10 dollars per lot; for the others it depends on the current exchange rate.
Mistakes to avoid
- Deciding entry by feel and only then sizing, instead of sizing from the stop
- Treating maximum leverage as a target: leverage doesn't change the risk your stop defines
- Ignoring spread and slippage, which widen the real loss at the stop
Frequently asked questions
How much should I risk per trade?
Many professional traders risk between 0.25% and 2% of the account per trade. The less you risk, the longer you survive a losing streak. There is no single right percentage for everyone.
What is a standard lot?
A standard lot is 100,000 units of the base currency. A mini lot is 0.1 lots (10,000 units) and a micro lot is 0.01 lots (1,000 units).
Does it work for gold too?
Yes: pick XAUUSD from the menu. It assumes a 100-ounce contract with a 0.01 pip (the most common convention among brokers); check your broker's specifications, as some use a different one.