Position Size Calculator — Trade the Right Size Every Time
Position sizing is the single most important skill in trading, yet it is also the most neglected. Our free position size calculator helps you calculate exactly how large a position to take based on your account balance, the percentage of capital you are willing to risk per trade, your stop-loss distance, and your entry price. Whether you trade forex, crypto, or stocks, sizing each position so a single losing trade never threatens your account is the foundation of a strategy that survives long enough to be profitable. Enter your account balance, risk percentage, stop-loss, and entry price above to instantly see the correct position size in units, the equivalent lot size for forex, the dollar amount at risk, and the implied leverage.
Why Position Sizing Determines Survival
Most new traders focus on entry signals and ignore position sizing, then blow up their accounts when a string of losses exceeds what the capital can absorb. The professional approach inverts this: decide first how much capital you are willing to lose on a trade if your stop-loss is hit, then size the position so that worst-case loss equals that fixed amount. Risking 1 percent of your account per trade means it would take roughly 70 consecutive losing trades to wipe out the account, which is virtually impossible for any disciplined strategy, while risking 10 percent per trade means just seven losses in a row — a common streak in volatile markets — can end the account. The calculator turns this principle into a concrete number, so you never enter a trade sized by gut feel or by a "round number" of lots that ignores your actual risk.
How the Calculation Works
The core formula is simple: position size equals risk amount divided by stop-loss distance. The risk amount is your account balance multiplied by the percentage you are willing to risk (for example, 1 percent of a $10,000 account is $100). The stop-loss distance is how far, in price or pip terms, your stop sits from your entry. Dividing the risk amount by the stop distance gives the number of units you can buy or sell so that, if the stop is hit, you lose exactly the risk amount and no more. For forex, the calculator converts units into standard lots (100,000 units per lot) so you can size trades in the lots your broker quotes. The implied leverage figure shows how much exposure your position represents relative to your account, which is useful for confirming the position does not exceed your broker's margin limits or your own risk tolerance.
Adapting the Calculator to Forex, Crypto, and Stocks
The risk-based formula applies to every market, but the units differ. In forex, the stop-loss distance is typically measured in pips, and the calculator expresses the result in lots. In crypto, where position sizes are quoted in coins or contracts, the stop-loss is measured in price or percentage terms, and the calculator gives the position in units you then convert to your exchange's contract size. In stocks, the stop-loss is the price difference between entry and stop, and the result is the number of shares to trade. Whatever the market, the principle is identical: the position is the size at which a stop-out equals your predetermined risk. Use the instrument selector above to match the calculator's output to the market you trade so the lot and leverage figures are meaningful.
Money Management Principles That Pair with Sizing
Position sizing is one part of a disciplined money management system. Keep your risk per trade consistent — 1 to 2 percent is the professional standard — so that no single trade can derail the account. Avoid correlated positions that effectively multiply your risk: holding five long positions on highly correlated currency pairs is not five independent 1 percent risks, it is one larger risk. Scale your risk down during high-volatility periods (major news, central bank announcements) when stop-losses are more likely to be gapped through, widening the actual loss beyond the planned risk. Re-calculate position size for every trade from your current account balance, not your starting balance, so the risk percentage stays constant as the account grows or shrinks. The calculator makes this trivial: enter your current balance each time, and the position it returns always reflects your live capital.
Frequently Asked Questions
What risk percentage should I use per trade? 1 to 2 percent of your account is the widely recommended range. It keeps any single loss manageable while allowing meaningful compounding when the account grows.
Does the calculator account for spreads and commissions? It uses the stop-loss distance you enter. In practice, spreads and commissions widen the real loss slightly, so size a touch more conservatively or factor them into your stop distance.
What is a standard lot in forex? A standard lot is 100,000 units of the base currency. The calculator converts your position in units to lots by dividing by 100,000 so you can match broker quoting.
Bookmark this position size calculator to size every trade based on your actual risk, and never enter a position sized by guesswork again.
