Forex Position Size & Lot Size Calculator
Size your trade: units, lots, pip value, and margin required
Risk Amount = Balance x Risk%
Units = Risk Amount / (Stop Pips x Pip Size)
Lots = Units / Contract Size
Margin = Notional / Leverage
Why Position Sizing Matters
Position sizing is the single most important risk control in forex trading, more important than any entry signal. The idea is simple: decide in advance the fixed percentage of your account you are willing to lose on one trade, often 0.5 to 2 percent, and then size the position so that hitting your stop loss costs exactly that amount. This keeps a losing streak from doing lasting damage, because each loss is a small, known fraction of your capital rather than a random dollar figure. It also removes emotion from the decision, since the math tells you how large to trade instead of your confidence in the setup. Traders who skip this step tend to oversize after wins and freeze after losses, which is how accounts get wiped out. Set the risk first, place the stop where your idea is wrong, and let the calculator solve for the size.
Standard, Mini, and Micro Lots
Forex is traded in standardized quantities called lots, and the lot type simply sets how many units of the base currency one lot represents. A standard lot is 100,000 units, a mini lot is 10,000 units, and a micro lot is 1,000 units. That means one micro lot is a tenth of a mini lot and a hundredth of a standard lot, so the same account can trade far smaller size with micro lots. Choosing a smaller lot type gives you finer control over risk, which matters most on small accounts or wide stops. The calculator first solves for the exact number of units your risk allows, then divides by the contract size of the lot type you pick to express that as a lot count. Whichever lot type you choose, the underlying risk in dollars stays the same, since it is set by your stop and risk percent, not by the label on the size.
Pips and Pip Value
A pip is the standard unit of price movement in forex, equal to 0.0001 for most pairs and 0.01 for pairs quoted against the Japanese yen. Pip value is how much money one pip of movement is worth for your position, and it scales with size: for a standard lot of a typical pair, one pip is worth about 10 in the quote currency. Your stop loss distance in pips multiplied by the pip value gives the dollar amount at risk, which is exactly what the calculator holds equal to your chosen risk percent. Getting the pip size right matters, because using 0.0001 on a yen pair, or 0.01 on a normal pair, scales the whole position by 100 times. This tool assumes the pip value is expressed in your account currency, the standard case taught in lot-size lessons, so pick Standard or JPY to match the pair you are trading.
Leverage and Margin
Leverage lets you control a large notional position with a smaller amount of deposited capital called margin. Margin required equals the notional value, which is units times the entry price, divided by your leverage ratio: at 30:1 a 55,000 notional ties up about 1,833, while 100:1 ties up only about 550. It is important to understand that leverage does not change your risk on the trade, which is fixed by your stop distance and position size, not by the leverage number. What leverage changes is how much of your account is locked as margin and how close you sit to a margin call if price moves against you. Using less margin than the maximum your broker allows leaves a buffer of free equity, which reduces the chance of a forced liquidation during normal volatility. Treat leverage as a capital-efficiency setting, and let your stop and risk percent, not the leverage, decide how much you can lose.