Financial Calculators
Position Size Calculator
Calculate position size, risk amount, and risk-to-reward ratio from your account size, risk percentage, entry price, and stop-loss price.
Enter the size of your trading account, the percentage you are willing to risk, the entry price, and the stop-loss price. Add a target price to see the potential profit and the risk-to-reward ratio. The position size is the number of units that keeps the loss at the stop inside your risk budget. Everything runs locally in your browser; your values are not uploaded or stored.
Size every trade from the amount you are willing to lose.
Position sizing turns a risk budget into a quantity. The risk budget is account size multiplied by the risk percentage, risk per unit is the distance between the entry price and the stop-loss price, and position size = floor(risk budget divided by risk per unit). For a 10,000 dollar account risking 2% with an entry of 50 and a stop of 48, the risk budget is 200, risk per unit is 2, and the position size is 100 units worth 5,000, which is 50% of the account. A stop above the entry is treated as a short position, and adding a target price shows the potential profit and the risk-to-reward ratio. The result ignores commissions, slippage, overnight gaps, and margin rules, so treat it as a planning estimate rather than a guarantee. This private browser estimate is not investment advice; your values are not uploaded or stored.
Frequently Asked Questions
Everything you need to know about this tool, how it works, and privacy.
How do I calculate position size?
Position size = floor((account size × risk percentage) ÷ |entry price − stop-loss price|). The risk percentage sets your risk budget, and the distance from entry to stop sets how much each unit can lose. With a $10,000 account, a 2% risk budget, an entry of $50, and a $48 stop, the risk budget is $200, each unit risks $2, and the position size is 100 units.
How much should I risk per trade?
There is no single correct number, but many traders risk 1% to 2% of the account per trade so a losing streak cannot force a deep drawdown. The calculator flags risk above 5% as unusually aggressive. Choose the amount you can accept losing and check it against your own trading plan.
What does the risk-to-reward ratio mean?
A 3:1 ratio means risking 1 unit of the account to make 3 units if the target is reached. At that ratio a win rate above 25% stays profitable before costs, because the break-even win rate is 1 ÷ (1 + ratio). Ratios below 1:1 need a win rate above 50% to break even.
Does it work for short positions and forex contracts?
Yes. When the stop-loss price sits above the entry price, the calculator treats the trade as a short position and keeps the same risk formula. The result is a count of units, but it does not model contract multipliers, pip values, or minimum lot sizes, so scale it to your instrument.
Do my values stay private, and is this investment advice?
Yes. The calculation and the copy action run locally in your browser, and CodeASystem does not upload or store the values you enter. The result ignores commissions, slippage, overnight gaps, and margin requirements, so it is a planning estimate rather than investment advice.