Position Size Calculator
Calculate lot size based on your risk percentage
The most critical tool for forex traders. Calculate the exact lot size to trade based on your account balance, risk tolerance, and stop loss distance. Prevent over-leveraging and protect your capital with precise position sizing.
This forex lot size calculator applies industry-standard position sizing formulas so every trade respects your predefined risk. Enter your balance, choose a risk percentage, and the tool instantly produces a broker-ready lot size plus risk-per-pip data. Use it before committing to any setup to keep your risk-reward profile consistent and compliant with your trading plan.
Traders searching for a dependable forex risk calculator rely on this page because it combines live market pricing with risk rules from our risk management module, ensuring your position sizing workflow stays fast, repeatable, and error-free.
Trading Calculators
How to Use This Calculator
Quick Start Guide
Follow these steps to calculate your optimal position size. This process should take less than 30 seconds once you have your trade plan ready.
Enter Your Account Balance
Input your current trading account balance, not your initial deposit. If you started with $5,000 and now have $4,500, enter $4,500. Position sizing should always be based on your real-time account value.
Set Your Risk Percentage
Choose how much of your account to risk on this trade. Professional traders typically use 1-2% per trade. Beginners should start with 0.5-1%. Never risk more than 5% on a single trade.
Input Stop Loss Distance
Enter the distance from your entry price to your stop loss in pips. This should be based on your technical analysis—support/resistance levels, volatility (ATR), or chart patterns.
Don't set stop loss to fit your desired position size. Set it based on technical levels, then let the calculator determine your lot size.
Select Your Currency Pair
Choose the forex pair or CFD instrument you want to trade. The calculator automatically adjusts pip values based on the instrument and current market price.
Get Your Position Size
The calculator displays your optimal lot size. Enter this exact number in your trading platform's "Volume" or "Lot Size" field when placing the order.
Why Position Sizing Is Critical
Position sizing is the single most important factor in determining whether you'll survive as a forex trader. More accounts are blown by poor position sizing than by bad analysis, poor timing, or unlucky trades.
The Math Behind Account Blow-Ups
Here's why proper position sizing isn't optional—it's survival:
❌ Without Position Sizing
- • Trade 1.0 lot on $5,000 account
- • 50 pip loss = -$500 (10% drawdown)
- • 3 losses = -$1,500 (30% drawdown)
- • Need 43% gain to recover
- → Account crippled
✅ With 1% Risk Per Trade
- • Trade 0.10 lot on $5,000 account
- • 50 pip loss = -$50 (1% drawdown)
- • 3 losses = -$150 (3% drawdown)
- • Need 3.1% gain to recover
- → Account protected
The 1% Rule Explained
Professional traders follow the 1% rule: never risk more than 1% of your account on a single trade. This isn't because they're scared—it's because math forces this discipline:
| Consecutive Losses | Risking 1% | Risking 5% | Risking 10% |
|---|---|---|---|
| 5 losses | -4.9% | -22.6% | -41.0% |
| 10 losses | -9.6% | -40.1% | -65.1% |
| 15 losses | -14.0% | -53.7% | -79.4% |
Notice how risking 10% per trade leaves you with only 20% of your capital after 15 losses, while 1% risk keeps you at 86% of your starting balance. This is why every professional trader uses position size calculators—it's not optional, it's survival.
Real-World Example: Two Traders
Trader A (Uses Calculator)
- • $10,000 account
- • Risks 1% per trade ($100)
- • Hit 10-trade losing streak
- • Account: $9,044 (90.4% intact)
- → Still trading
Trader B (Ignores Calculator)
- • $10,000 account
- • "Feels right" (10% per trade)
- • Hit 10-trade losing streak
- • Account: $3,487 (34.9% intact)
- → Account destroyed
Understanding the Position Size Formula
Our calculator uses this industry-standard formula to determine your optimal lot size:
Position Size = (Account Balance × Risk %) ÷ (Stop Loss in Pips × Pip Value)
Account Balance
$10,000
Risk %
1% ($100)
Stop Loss
50 pips
Pip Value
$10/pip
Calculation:
$100 ÷ (50 × $10) = $100 ÷ $500 = 0.20 lots
Step-by-Step Manual Calculation
While the calculator does this instantly, understanding the math helps you verify results and trade with confidence:
Step 1: Calculate Risk Amount
Account Balance × Risk % = Risk Amount
$10,000 × 1% = $100
Step 2: Calculate Total Risk in Pips
Stop Loss Distance × Pip Value = Total Risk
50 pips × $10/pip = $500 per lot
Step 3: Calculate Position Size
Risk Amount ÷ Total Risk = Position Size
$100 ÷ $500 = 0.20 lots
Pip values vary by currency pair and account currency. For EUR/USD with USD account, 1 pip on 1 standard lot ≈ $10. For JPY pairs, use 0.01 as pip size (not 0.0001). For exotic pairs or non-USD accounts, pip values differ significantly. The calculator handles all these variations automatically.
Common Position Sizing Mistakes
✗Trading Without Calculating Position Size
"I'll just trade 0.1 lots on everything" is the fastest path to account destruction. Position size must adapt to stop loss distance.
Why it fails: A 20-pip stop needs different position size than 100-pip stop to maintain same risk.
✗Setting Stop Loss to Fit Desired Position Size
"I want to trade 1.0 lot, so I'll put my stop closer." This is backwards and leads to getting stopped out on normal price movement.
Correct approach: Place stop loss at technical level, then calculate position size.
✗Using Stale Account Balance
Calculating position size based on your starting balance ($10,000) when your current balance is $7,500. This over-leverages your actual capital.
Solution: Always use current balance for calculations.
✗Ignoring Correlated Positions
Trading EUR/USD and GBP/USD simultaneously with full position sizes. These pairs correlate ~80%, so you're actually risking 1.8x your intended amount.
Solution: Reduce position size when holding correlated pairs.
✗Forgetting to Account for Spread
Your calculated stop is 50 pips, but you forgot that the 2-pip spread means your actual risk is 52 pips on entry.
Solution: Add spread to your stop loss distance in the calculator.
Related Forex Calculators
Frequently Asked Questions
What is position sizing in forex?
Position sizing is the process of determining how many lots or units to trade based on your account balance and risk tolerance. It's the most important aspect of risk management, ensuring you don't risk too much on any single trade. Without proper position sizing, even the best trading strategy will fail.
What position size should I use as a beginner?
Beginners should risk no more than 1% of their account per trade. With a $1,000 account, this means risking $10 per trade. The position size calculator will determine the exact lot size needed to maintain this risk level based on your stop loss. Most beginners should start with 0.01 micro lots and gradually increase as they prove profitability.
How do I calculate position size manually?
The formula is: Position Size = (Account Balance × Risk %) ÷ (Stop Loss in Pips × Pip Value)
Example: ($5,000 × 1%) ÷ (50 pips × $10/pip) = $50 ÷ $500 = 0.10 lots (1 mini lot). However, using a calculator is faster and eliminates math errors.
What lot size should I use with a $100 account?
With a $100 account risking 1% ($1 per trade), you should use 0.01 micro lots (1,000 units) with a 10-pip stop loss on EUR/USD. Never use standard or mini lots with small accounts as this violates proper risk management. Many brokers don't support proper position sizing for accounts under $500, which is why we recommend starting with at least $1,000.
Should I increase position size after winning trades?
Position size should scale with your account balance, not your emotions. If your account grows from $10,000 to $11,000, your position size naturally increases because you're still risking 1% (now $110 instead of $100). Never increase risk percentage after wins—that's how accounts blow up during drawdowns.
How do I enter the calculated lot size in MetaTrader?
In MetaTrader 4 or 5, the "Volume" field when placing an order uses lot notation. If the calculator shows 0.15 lots, enter exactly "0.15" in the Volume field. Remember: 0.01 = 1 micro lot (1,000 units), 0.10 = 1 mini lot (10,000 units), 1.00 = 1 standard lot (100,000 units).
Master Forex Risk Management
Position sizing is just one aspect of risk management. Learn comprehensive strategies for protecting your capital in our free forex trading course.
Learn Risk Management →