Position Sizing Fundamentals

Position sizing determines how much you risk on each trade. It's one of the most important aspects of risk management.

Why Position Sizing Matters

Capital Protection

Purpose:

• Prevent large losses
• Survive losing streaks
• Preserve trading capital
• Stay in the game

Consistency

Benefits:

• Even risk per trade
• Predictable drawdowns
• Emotional stability
• Systematic approach

The Basic Concept

Risk Per Trade

Definition:

• Amount you could lose
• If stop loss is hit
• As percentage of account
• Controlled exposure

Common Guidelines

Our rule:

• Risk 1% of the account per trade, never more
• In your first live year, risk a fixed 0.5% per trade
• Stop for the day at a 2% loss

Why Percentage Based

Advantages:

• Scales with account
• Adjusts automatically
• Consistent relative risk
• Professional approach

Position Size Formula

The Calculation

Formula:

Position Size = (Account Risk Amount) / (Trade Risk in Pips × Pip Value)

Step by Step

Process:

1. Determine Account Risk

- Account size × Risk percentage - Example: $10,000 × 1% = $100

1. Determine Trade Risk

- Entry to stop loss distance - Example: 50 pips

1. Calculate Position Size

- $100 / (50 pips × $10 per pip) = 0.2 lots

Forex Position Sizing

Lot Sizes

Pip Value

For pairs quoted in USD (XXX/USD):

• Standard lot: $10 per pip
• Mini lot: $1 per pip
• Micro lot: $0.10 per pip

The $10 figure holds only for pairs quoted in US dollars. For other pairs the pip value is fixed in the quote currency and converted: on USD/JPY a standard lot moves ¥1,000 per pip, about $6.70 at a rate of 150; on USD/CHF it is CHF 10, about $11.40-12.50 at 0.88-0.80.

Example Calculation

Scenario:

• Account: $5,000
• Risk: 1% = $50
• Stop loss: 25 pips
• Pair: EUR/USD

Calculation:

• $50 / 25 pips = $2 per pip
• $2 / $10 per standard lot = 0.2 lots
• Trade 2 mini lots or 20 micro lots

Stock Position Sizing

Share Calculation

Formula:

Shares = Account Risk / (Entry - Stop Loss)

Example

Scenario:

• Account: $25,000
• Risk: 1% = $250
• Entry: $100
• Stop: $95 (risk = $5 per share)

Calculation:

• $250 / $5 = 50 shares

Position Sizing Tools

Calculators

Options:

• Online calculators
• Platform tools
• Spreadsheets
• Mobile apps

What You Need

Input Required:

• Account size
• Risk percentage
• Entry price
• Stop loss price
• Pip value (if forex)

Adjusting Position Size

When to Reduce

Situations:

• During drawdowns: 75% of normal size at 5-10% below your peak, 50% at 10-15%, stop trading at 15%
• Your first live year: a fixed 0.5% per trade
• A wider stop loss means a smaller position, not more risk

Confidence Does Not Change Size

Size every trade from the same 1% risk and your stop distance: lots = (account × 1%) ÷ (stop pips × pip value). How sure you feel about a setup never changes the size. The move from 0.5% to 1% comes after your first live year, not after a good run.

Never Exceed Limits

Rules:

• Maximum risk per trade
• Regardless of confidence
• Rules protect you
• No exceptions

Common Mistakes

Trading Too Large

Problem:

• Risking too much
• Account volatility
• Emotional pressure
• Quick destruction

Solution:

• Stick to 1% (0.5% in your first live year)
• Calculate every trade
• Err on smaller side

Fixed Lot Sizes

Problem:

• Same size regardless
• Different risk per trade
• Inconsistent exposure
• No adjustment

Solution:

• Calculate each trade
• Adjust for stop distance
• Consistent percentage risk

Ignoring Stop Distance

Problem:

• Same position, different stops
• Wider stop = more risk
• Not truly risk-managed

Solution:

• Always factor stop distance
• Position size varies with stop
• Risk stays constant

Practical Tips

Round Down

Best Practice:

• Round to smaller size
• Not larger
• Extra margin of safety
• Never over-risk

Use a Checklist

Before Each Trade:

• [ ] Account balance noted
• [ ] Risk percentage set
• [ ] Stop loss identified
• [ ] Position size calculated
• [ ] Size verified before entry

Document Everything

Record:

• Size calculation
• Risk amount
• Actual position
• For each trade

Key Takeaways

• Position sizing controls risk per trade
• Risk 1% per trade; a fixed 0.5% in your first live year
• Calculate size based on stop loss distance
• Use the formula: Risk Amount / Trade Risk
• Forex uses lots, stocks use shares
• Use calculators for accuracy
• Reduce size during drawdowns
• Never exceed maximum risk limits
• Calculate for every trade
• Round down when in doubt

What's Next?

Learn about risk/reward ratios and their importance.

This article is for educational purposes only and does not constitute financial advice.