Position Size Calculator — Forex Lot Size & Risk Management

Enter your account balance, then use the slider to set your risk percentage per trade (most professional traders use 1–2%). Select your currency pair to use the correct pip value, then enter your entry price and stop loss price.

The calculator computes the stop loss distance in pips automatically from your entry and stop loss prices, then calculates the position size that limits your dollar risk to exactly your chosen percentage of the account. Results are shown in standard lots, mini lots, micro lots, and units.

Tip: Most retail brokers support micro lots (0.01 lots = 1,000 units). If the calculator shows a position size smaller than 0.01 lots, your stop loss is too wide for your account size and risk percentage — tighten the stop or reduce leverage.

The position sizing formula:

• Dollar Risk = Account Balance × (Risk % ÷ 100)
• Stop Loss (pips) = |Entry Price − Stop Loss Price| × 10,000
• Position Size (lots) = Dollar Risk ÷ (Stop Loss in pips × Pip Value per lot)

For major USD pairs (EUR/USD, GBP/USD, etc.), the pip value is $10 per pip per standard lot. For USD/JPY the pip is the second decimal place, and the pip value changes with the exchange rate.

Example: $10,000 account, 1% risk, 50-pip stop loss on EUR/USD:

• Dollar Risk = $10,000 × 1% = $100
• Position Size = $100 ÷ (50 pips × $10) = 0.20 standard lots

Example 1 — Conservative Trade ($5,000 Account)

• Account: $5,000 | Risk: 1% = $50
• Pair: EUR/USD | Entry: 1.0850 | SL: 1.0800 (50 pips)
• Position size = 0.10 lots (1 mini lot, 10,000 units)

Example 2 — Tighter Stop ($10,000 Account)

• Account: $10,000 | Risk: 1% = $100
• Pair: GBP/USD | Entry: 1.2650 | SL: 1.2620 (30 pips)
• Position size = 0.33 lots (33,000 units)

Why Fixed Percentage Sizing Works

Fixed percentage position sizing is one of the most effective risk management techniques. By risking the same percentage on every trade (not the same dollar amount), your position sizes automatically scale down during drawdowns (protecting your account) and scale up as your account grows (compounding gains). A 10-trade losing streak at 1% risk reduces your account by only 9.6%, not 10%.