Position Sizing: How Much to Risk Per Trade
Last updated: November 2026 · 3 min read · Educational content, not financial advice
Key takeaways
- Size the position from the stop: Position = Risk amount ÷ (Stop distance × value per unit).
- Percentage risk is what controls drawdown: ten losses at 1% cost about 9.6%, at 5% about 40%.
- Leave room under prop firm daily and overall limits, and treat full Kelly as an upper bound only.
Position sizing decides how much of your account is at stake on each trade. Two traders with the same entries and exits can end up with completely different results because one risks 0.5% per trade and the other risks 5%. Most trading accounts are lost through oversizing, not through bad entries.
The core rule: risk a fixed percentage
Choose the amount you are willing to lose if the trade hits its stop, as a percentage of your account. Then work backwards to find the position size that produces exactly that loss.
Position size = Risk amount ÷ (Stop distance × Value per unit of distance)
Worked forex example
Account: $10,000. Risk: 1%. Pair: EUR/USD. Stop distance: 25 pips.
- Risk amount = $10,000 × 1% = $100
- For a USD-quoted pair, one pip on a standard lot (100,000 units) is worth about $10.
- Lots = $100 ÷ (25 pips × $10) = 0.40 lots (40,000 units)
Check: 0.40 lots is worth $4 per pip, and 25 pips × $4 = $100. If the stop is hit you lose 1% of the account, no more. Pip values differ for other pairs and for accounts not denominated in USD, and indices, metals and crypto use their own contract sizes, so always take the value per point from your broker’s specification.
Notice that a wider stop means a smaller position. The stop goes where the trade idea is wrong, and the size adjusts to it. The reverse, picking a size first and squeezing the stop to fit, is how risk gets out of control.
What risk per trade does to a losing streak
A series of losses is normal for any strategy. The table shows the percentage of the account lost after consecutive full losses, with percentage risk (compounding):
| Risk per trade | 3 losses | 5 losses | 10 losses |
|---|---|---|---|
| 0.5% | 1.5% | 2.5% | 4.9% |
| 1% | 3.0% | 4.9% | 9.6% |
| 2% | 5.9% | 9.6% | 18.3% |
| 5% | 14.3% | 22.6% | 40.1% |
| 10% | 27.1% | 41.0% | 65.1% |
At 1%, ten losses in a row leave you down under 10%. At 5%, the same streak takes about 40% of the account, and recovering from that takes a 67% gain (see the drawdown guide).
Risk limits at prop firms
Funded-account challenges usually set a maximum daily loss and a maximum overall loss. Rules differ between firms, so read yours carefully. As an illustration, take a $100,000 account with a 5% daily and 10% overall limit. At 1% risk, one full loss costs $1,000, so five full losses in a day reach the daily limit. At 0.5% risk it would take ten. Your risk per trade should leave comfortable room under every limit, including the cases where several trades go wrong together.
A note on the Kelly criterion
The Kelly formula, f = W − (1 − W) ÷ R, gives the fraction of capital that maximizes long-run growth if your win rate and ratio are known exactly. For a 55% win rate at 1:2 it suggests 32.5%, which would produce brutal drawdowns. Because your true edge is never known exactly, practitioners who use Kelly at all usually use a small fraction of it. Treat it as an upper bound, not a target.
A simple checklist before every trade
- Where is the stop, and is it where the idea is actually wrong?
- What is the risk in money, and is it within my per-trade percentage?
- What position size gives exactly that risk at that stop distance?
- What would my account look like after a streak of losses at this size?
Try the numbers yourself
Compare risk levels in the calculator.
Related guides
This guide is for education only. It is not financial advice or a trade recommendation, and trading involves substantial risk of loss. See the Terms of Service.