Determine the optimal lot size for any trade based on your account balance, risk tolerance, and stop loss distance. The #1 risk management tool for traders.
Lots = Risk Amount ÷ (SL Pips × Pip Value per Lot)
Example: $10,000 acct · 1% risk · 20-pip SL on EUR/USD: $100 ÷ (20 × $10) = 0.50 lots
Position size = (Account balance × Risk %) / (Stop loss in pips × Pip value per lot). For example, with $10,000 balance, 1% risk, and 20-pip stop loss on EUR/USD: (10,000 × 0.01) / (20 × $10) = 0.50 lots.
Most professional traders risk 1-2% of their account per trade. Beginners should start with 0.5-1%. Never risk more than 5% on a single trade.
Position sizing prevents catastrophic losses. Even with a 50% win rate, proper position sizing ensures you survive losing streaks and grow your account over time.
Leverage doesn't change your position size calculation — it only determines how much margin you need. Your risk per trade should always be based on account balance, not available leverage.
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Calculator results are estimates only — not financial advice. Trading involves significant risk of loss. Full risk disclosure.
1.0% risk — Professional (recommended)
Recommended Lot Size
0.50 lots
50,000 units
Risk amount
$100.00
$/pip per lot
$10.00
Stop loss
20 pips
Position Size by Risk Level
| Risk % | Risk $ | Lot Size |
|---|---|---|
| 0.5% | $50 | 0.25 |
| 1%← current | $100 | 0.50 |
| 2% | $200 | 1.00 |
| 3% | $300 | 1.50 |
Kelly Criterion
Full Kelly
25.0%
Max growth — very risky
½ Kelly (recommended)
12.5%
Standard practice
¼ Kelly (conservative)
6.3%
Smoother equity curve
K% = W − (1−W) ÷ R · where W = win rate, R = avg win ÷ avg loss. Use ½ Kelly — full Kelly causes large drawdowns from variance.
Losing Streak Probability — 55% win rate · 1.0% risk/trade
| Consecutive Losses | Probability | Balance After |
|---|---|---|
| 2 in a row | 20.25% | $9,801.00 |
| 3 in a row | 9.11% | $9,702.99 |
| 4 in a row | 4.10% | $9,605.96 |
| 5 in a row | 1.85% | $9,509.90 |
| 7 in a row | 0.37% | $9,320.65 |
| 10 in a row | 0.03% | $9,043.82 |
Probability = (1 − win rate)^N · Balance assumes fixed % risk with no adjustment between trades.
Risk of Ruin — 55% win rate · 1.5R
| Risk / Trade | Risk of Ruin |
|---|---|
| 0.5% | <0.01% |
| 1%← current | <0.01% |
| 2% | <0.01% |
| 3% | <0.01% |
Edge = W×R−(1−W) = 37.50% · RoR = ((1−edge)/(1+edge))^(100/risk%) · Assumes fixed % risk, no account top-ups.
Portfolio Risk Tracker
Formula: risk amount ÷ (stop loss pips × pip value per lot). Professional traders risk 1–2% per trade.