Position Size Calculator
Enter your account size, the percentage you're willing to risk, and your entry and stop. Get the exact position size that keeps your risk fixed on every trade.
Free tool · No sign-up · Updated July 2026
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Your position
Estimates for planning only — verify against your broker. Nothing here is financial advice.
How the position size calculator works
Consistent position sizing is the single biggest lever most traders ignore. Risking a fixed, small percentage of your account per trade means no one loss can sink you — and it makes your results comparable trade to trade. This calculator turns your risk rule into an exact share or contract count in one step.
- Your dollar risk is your account size multiplied by the percentage you choose to risk (1–2% is a common ceiling).
- Your per-share risk is the distance between your entry and your stop-loss.
- Dividing the two gives the position size that makes your worst case exactly the risk you set.
Stop calculating by hand — TradeOlogy does this automatically
Broker auto-sync, a fully customizable analytics dashboard, and a built-in trade simulator - at roughly half the price of the big names.
Learn the fundamentals
Go beyond the numbers. These free TradeOlogy Academy lessons cover the theory behind this calculator.
Position Sizing Deep Dive
The full method behind risk-based sizing — fixed-fractional risk, scaling in, and why 1% is the professional default.
Read the lesson ↗ Academy lessonRisk Management Foundations
How disciplined traders think about protecting capital before they think about profit.
Read the lesson ↗ Academy lessonStop Placement Masterclass
Where to place a stop so the per-share risk this calculator needs is actually valid.
Read the lesson ↗Related calculators
Position Size Calculator — FAQ
What percentage should I risk per trade?
Most professional traders risk 1% or less of their account on any single trade, and rarely more than 2%. Risking small means a losing streak is survivable and no single trade can do real damage to your account.
Does this work for stocks, futures and forex?
The share/unit math is universal — account × risk % ÷ per-unit risk. For futures you would divide by the per-contract risk (stop distance × the contract's point value); for forex, by the pip risk × pip value. Use our futures and pip calculators alongside this one.
Why size by risk instead of a fixed dollar amount?
A fixed dollar amount ignores where your stop is. Risk-based sizing gives you a bigger position when your stop is tight and a smaller one when it's wide, so your actual dollar loss is the same either way — which is what real consistency means.