Forex Lot Size Calculator
Enter your risk % and stop loss distance — get the correct lot size. No more over-leveraging forex trades.
Inputs
$10 for most USD pairs, varies for others
How to Calculate Forex Lot Size
Lot sizing in forex determines how many units of currency to trade per position. Trade too large and a normal stop loss wipes out your account. Trade too small and your winners barely move the needle. This calculator gets it exactly right.
Enter your account balance, risk percentage per trade, stop loss distance in pips, and the pip value for your pair. The calculator outputs the correct lot size — standard (100,000), mini (10,000), micro (1,000), or fractional lots.
This is the forex equivalent of position sizing in stocks. The logic is identical: divide your dollar risk by the cost of your stop loss to find the correct size. The only difference is that forex uses lots instead of shares, and the stop loss is measured in pips instead of dollars.
Formula
Lot Size = (Account Balance × Risk %) ÷ (Stop Loss in Pips × Pip Value per Standard Lot)
Example
Account: $5,000. Risk: 1% = $50. Stop loss: 30 pips. Pip value on EUR/USD standard lot: $10.
Lot size = $50 ÷ (30 × $10) = $50 ÷ $300 = 0.167 standard lots (approximately 1.67 mini lots or 16.7 micro lots).
Most brokers allow fractional lots, so you'd enter 0.17 lots. Your actual risk: 30 pips × $10 × 0.17 = $51 (approximately 1% of account).
Frequently Asked Questions
What is a lot in forex trading?
A lot is a standardized unit of currency in forex. A standard lot is 100,000 units of the base currency. A mini lot is 10,000 units (0.1 standard). A micro lot is 1,000 units (0.01 standard). Lot size directly determines your position size and risk per pip.
What lot size should a beginner use?
Beginners should use micro lots (0.01 standard lots). At ~$0.10 per pip on EUR/USD, a 50-pip loss costs only $5. This lets you learn with real money without meaningful risk. Scale up to mini lots once you're consistently profitable over 2-3 months.
How do I know if I'm over-leveraging my forex trades?
If a single trade risks more than 2% of your account, you're over-leveraged. Calculate: (stop loss pips × pip value × lot size) ÷ account balance. If the result exceeds 0.02, reduce your lot size. This calculator does the math for you automatically.
Related Calculators
Forex Pip Calculator
Get the exact dollar value of a pip for any forex pair in your account currency. Majors, minors, and exotics.
Position Size Calculator
Enter your account size, risk %, and stop loss — get the exact number of shares or contracts to buy. Works for stocks, crypto, forex, and futures.
Trade Risk Calculator
Set your risk per trade using support levels or fixed percentages. Stop blowing accounts.
Disclaimer: This calculator is for educational purposes only and does not constitute financial advice. Trading involves substantial risk of loss. Past performance does not guarantee future results. Always do your own research and consult with a licensed financial advisor before making investment decisions.