Position Sizing Guide
Calculate the perfect lot size for every trade
What is Position Sizing?
Position sizing is determining how many lots (units) to trade based on your account size, risk tolerance, and the stop-loss distance. It's the bridge between your risk management rules and actual trade execution.
The Position Sizing Formula
Position Size (lots) =
(Account Size × Risk %) ÷ (Stop-Loss in Pips × Pip Value)
Don't worry if this looks confusing—we'll break it down step-by-step with real examples below.
Right Position Sizing
Risk 1% per trade = Can survive 50+ losses before account blow-up
Wrong Position Sizing
Risk 10% per trade = 7 losing trades and you've lost half your account
The Golden Rule: Risk 1-2% Per Trade
Professional traders risk 1-2% of their account per trade. Not per day, not per week—per trade. This is the single most important rule in trading.
Why 1-2% is the Magic Number
- 1% risk: You can lose 50 trades in a row and still have half your account left
- 2% risk: You can lose 35 trades in a row before halving your account
- 10% risk: Just 7 losses cuts your account in half (this is why 90% of traders fail)
Step-by-Step Position Sizing Calculation
Let's walk through a real example to show you exactly how to calculate position size.
Example: EUR/USD Long Trade
Calculation:
Dollar Risk = $10,000 × 1% = $100
Risk in Pips = 50 pips
Position Size = $100 ÷ (50 pips × $10 per pip)
Position Size = $100 ÷ $500 = 0.2 lots
Understanding Lot Sizes
Forex trades are measured in lots. Different lot sizes have different pip values.
Standard Lot
Pip Value: $10/pip
Most common for accounts $10,000+
Mini Lot
Pip Value: $1/pip
Good for accounts $1,000-$10,000
Micro Lot
Pip Value: $0.10/pip
Perfect for beginners ($100-$1,000)
More Position Sizing Examples
Example 2: Small Account (Micro Lots)
Account: $500
Risk: 2% = $10
Stop-Loss: 30 pips
Pip Value (micro lot): $0.10/pip
Position Size = $10 ÷ (30 pips × $0.10) = $10 ÷ $3 = 3.33 micro lots
Round down to 3 micro lots to stay under your risk limit.
Example 3: Larger Account (Standard Lots)
Account: $50,000
Risk: 1% = $500
Stop-Loss: 40 pips
Pip Value (standard lot): $10/pip
Position Size = $500 ÷ (40 pips × $10) = $500 ÷ $400 = 1.25 standard lots
Can trade 1.25 lots or round to 1.2 lots for easier management.
Example 4: Tight Stop-Loss
Account: $10,000
Risk: 1% = $100
Stop-Loss: 20 pips (tight scalping stop)
Pip Value (standard lot): $10/pip
Position Size = $100 ÷ (20 pips × $10) = $100 ÷ $200 = 0.5 standard lots
Position Sizing Recommendations by Account Size
$100 - $500 Account
- • Trade micro lots only (0.01 - 0.05 lots)
- • Risk 1-2% = $1-$10 per trade
- • Use tight 15-25 pip stop-losses
- • Focus on learning, not profit
$1,000 - $5,000 Account
- • Trade mini lots (0.1 - 0.5 lots)
- • Risk 1-2% = $10-$100 per trade
- • Can use 30-50 pip stops comfortably
- • Ideal for strategy testing
$10,000+ Account
- • Trade standard lots (0.5 - 2.0+ lots)
- • Risk 1% = $100+ per trade
- • Can handle wider 50-100 pip stops
- • Professional-level trading
Common Position Sizing Mistakes
❌ Mistake #1: "I'll just trade 1 standard lot every time"
Why it's wrong: Different setups have different stop-loss distances. If you always trade 1 lot, sometimes you're risking 1%, sometimes 5%, sometimes 10%. Your risk is all over the place.
✅ Solution: Calculate position size fresh for every trade based on your stop distance.
❌ Mistake #2: "My account is small, so I'll risk 10% to grow it faster"
Why it's wrong: This guarantees you'll blow up. Even a 60% win rate means 4-5 losses in 10 trades. At 10% risk, you'd lose 40-50% of your account. Small accounts need more discipline, not less.
✅ Solution: Risk 1-2% regardless of account size. Grow it slowly and sustainably.
❌ Mistake #3: "I'll calculate position size mentally in my head"
Why it's wrong: Mental math leads to errors, especially under pressure. One miscalculation can risk 5% instead of 1%—and that one trade can hurt badly.
✅ Solution: Use a position size calculator (many brokers have built-in calculators, or use an Excel sheet).
❌ Mistake #4: "I'm confident in this trade, so I'll risk 5%"
Why it's wrong: Every trade feels like a winner before you take it. That's why you're taking it! But the market doesn't care about your confidence. Even "sure things" fail 30-40% of the time.
✅ Solution: Risk the same percentage on every trade, regardless of confidence level.
Position Sizing Tools & Calculators
Excel Spreadsheet Method
Create a simple Excel sheet with these columns:
A: Account Size
B: Risk % (1% or 2%)
C: Dollar Risk (=A*B)
D: Stop-Loss (pips)
E: Pip Value
F: Position Size (=C/(D*E))
Update A and D before each trade, and column F automatically shows your position size.
Online Calculators
Many free position size calculators exist online:
- MyFXBook Position Size Calculator: Simple and accurate
- BabyPips Calculator: Great for beginners
- Broker Platforms: MetaTrader 4/5 have built-in calculators
Quick Reference Table
| Account Size | 1% Risk | 50-pip Stop | Position Size |
|---|---|---|---|
| $500 | $5 | 50 pips | 0.01 lots (1 micro) |
| $1,000 | $10 | 50 pips | 0.02 lots (2 micro) |
| $2,500 | $25 | 50 pips | 0.05 lots (5 micro) |
| $5,000 | $50 | 50 pips | 0.10 lots (1 mini) |
| $10,000 | $100 | 50 pips | 0.20 lots (2 mini) |
| $25,000 | $250 | 50 pips | 0.50 lots (5 mini) |
| $50,000 | $500 | 50 pips | 1.00 lot (standard) |
*Based on standard lot pip value of $10/pip. Adjust proportionally for different stop-loss distances.
Key Takeaways
- Always risk 1-2% per trade—this is non-negotiable for long-term survival
- Calculate position size before every trade based on your stop-loss distance
- Use the formula: Position Size = (Account × Risk%) ÷ (Stop Pips × Pip Value)
- Tighter stops = larger position sizes while maintaining the same dollar risk
- Use calculators or spreadsheets—don't rely on mental math
- Small accounts need MORE discipline, not higher risk percentages
Continue Learning
Stop-Loss Strategies →
Now that you know how to size positions, learn where to place your stop-losses for maximum protection.
Risk-Reward Ratio →
Combine position sizing with risk-reward ratios to build a mathematically profitable trading system.
Leverage & Margin →
Understand how leverage affects your position sizing and overall risk management strategy.
← Back to Risk Management
Explore all risk management topics including money management rules and drawdown recovery.