Position Size Calculator
Size a trade from account balance, risk per trade, entry price, and stop-loss distance. Estimate shares, notional, and capital at risk.
Calculate position size
Enter account size, risk per trade, entry, and stop distance.
Position sizing helps estimate risk before a trade. It does not guarantee execution at the stop price. Slippage, spreads, fees, gaps, and volatility can increase real losses.
Enter account size and either risk % or a fixed risk amount. For long trades, stop is usually below entry; for short, stop is usually above entry. Results are planning estimates—not guaranteed execution.
Risk per trade above 5% of account is unusually high for many traders. Consider whether a lower risk assumption fits your plan.
Dollar exposure at entry
Educational estimate only. Not financial advice. Actual losses can exceed the calculated risk amount.
What is position sizing?
Position sizing estimates how many units to trade so that a stop-loss at your chosen price corresponds to a planned risk amount. It links account size, entry price, stop distance, and risk per trade into a single trade exposure figure.
This educational calculator works for stocks, ETFs, crypto, forex, indexes, and commodities when you enter prices in consistent units. It does not recommend trades or risk levels.
How position size is calculated
Risk amount = account size × risk %
Risk per unit = |entry price − stop-loss price|
Units = risk amount ÷ risk per unit
Position size = units × entry price
Stop distance % = risk per unit ÷ entry price × 100
Estimated total risk = risk amount + fees + slippage estimate
For short positions, risk per unit = stop-loss price − entry price when stop is above entry. Fixed risk amount overrides risk % when entered.
Position size calculator examples
Stock long position
Account $100,000 · risk 1% · entry $50 · stop $47
Risk $1,000 · ~333 units · position ~$16,667
A 6% stop distance on a long trade with 1% account risk produces a moderate dollar exposure relative to account size.
Short position
Account $50,000 · risk 1% · entry $100 · stop $105
Risk $500 · 100 units · position $10,000
For a short, stop is above entry. Risk per unit is $5 and position size is units × entry price.
Crypto position
Account $10,000 · risk 2% · entry $2,500 · stop $2,400
Risk $200 · 2 units · position $5,000
Higher asset prices and wider stops change unit count and dollar exposure for the same risk amount.
Smaller risk example
Account $25,000 · risk 0.5% · entry $200 · stop $195
Risk $125 · 25 units · position $5,000
Lower risk per trade reduces the dollar amount at risk if the stop is hit exactly.
How to read the result
- Risk amount is the estimated loss if the stop-loss is hit exactly at your stop price.
- Units / shares / lots show how much of the asset fits the selected risk and stop distance.
- Position size is the full dollar value of the trade at the entry price.
- Stop distance affects position size: tighter stops produce larger position sizes; wider stops produce smaller position sizes.
- Max loss if stop hit includes optional fees and slippage estimates on top of the base risk amount.
- Real losses can differ due to slippage, spreads, gaps, partial fills, and fees not modeled here.
Position size vs risk amount
Risk amount
The money you plan to lose if the stop is hit at the expected price. Set by account size × risk % or a fixed override.
Position size
The full trade exposure in dollars (units × entry price). A large position can still have a small planned risk if the stop is tight.
| Factor | Effect |
|---|---|
| Tighter stop | Larger position size for the same risk amount |
| Wider stop | Smaller position size for the same risk amount |
| Tight stops | May increase stop-out probability and execution risk |
| This calculator | Shows math only—it does not decide whether a trade is appropriate |
When to use this calculator
- Estimate trade size before entering a position
- Compare different stop-loss distances and their effect on units
- Keep risk per trade consistent across multiple setups
- Calculate units for stocks, crypto, forex, or indexes with your own prices
- Understand how entry and stop prices affect dollar exposure
This calculator is a planning tool. It does not guarantee stop execution or trading results.
Stop-loss, slippage and limitations
- Assumes the stop fills at the price you enter—gaps and fast markets can cause worse fills.
- Optional fee and slippage fields are rough estimates, not live spread data.
- Does not model leverage, margin requirements, or lot/pip conversions for all brokers.
- Does not account for partial exits, scaling in, or multiple targets.
- Past planning scenarios do not predict future trading outcomes.
See also: Break-Even Calculator for sell prices after fees, and Portfolio Allocation Calculator for weight-based planning.
Frequently asked questions
What is position size?
How do I calculate position size?
What risk percentage should I use?
Does this calculator work for long and short trades?
Does this calculator work for forex?
Does this include fees, spread, or slippage?
Can losses be larger than the calculated risk amount?
Is this position size calculator free?
Calculate position size by market
Trading involves risk of loss. CalculatorInvest provides educational tools only—not financial advice. Read our disclaimer.