Lot Size Calculator

What Is Lot Size in Forex?

In forex trading, a lot size is the standardized number of units of the base currency in a single trade. Understanding lot size is essential because it directly determines your risk exposure and potential profit or loss on every trade.

There are four common lot sizes used by traders worldwide:

• Standard lot — 100,000 units (1 pip ≈ $10 on USD pairs)
• Mini lot — 10,000 units (1 pip ≈ $1)
• Micro lot — 1,000 units (1 pip ≈ $0.10)
• Nano lot — 100 units (1 pip ≈ $0.01)

How to Calculate Lot Size in Forex

The lot size formula is straightforward. To calculate the correct position size for any trade, use this formula:

Here's a step-by-step example:

1. Account Balance = $10,000
2. Risk per trade = 1% → Risk Amount = $100
3. Stop Loss = 25 pips
4. Pip Value (EUR/USD, standard lot) = $10
5. Lot Size = $100 ÷ (25 × $10) = 0.40 standard lots

This calculator does all the math automatically — including live pip value adjustments for cross pairs where the pip value changes with the exchange rate.

Lot Size by Account Size

Choosing the right lot size depends on your account balance and risk tolerance. Here's a quick reference using 1% risk per trade and a 20-pip stop loss on EUR/USD:

Lot Size for Gold (XAUUSD) and Indices

Calculating lot size for XAUUSD (gold) and indices works the same way, but the pip value differs. For gold, 1 pip = $0.01 movement, and a standard lot is 100 ounces. This means each pip on a standard gold lot = $1 (compared to $10 for EUR/USD).

Our calculator supports gold and all major, minor, and cross pairs — the pip value is computed automatically from live market rates, so you always get the accurate lot size no matter what instrument you're trading.

Common Lot Sizing Mistakes to Avoid

• Using a fixed lot size — Your position size should change based on your stop loss distance. A wider stop = smaller lots, a tighter stop = larger lots.
• Risking too much per trade — Professional traders rarely risk more than 1–2% per trade. Even with a 60% win rate, risking 5%+ per trade can blow your account during a normal losing streak.
• Ignoring pip value on cross pairs — Pairs like GBP/JPY or EUR/AUD have pip values that change with the exchange rate. Using a calculator with live rates (like this one) prevents costly miscalculations.
• Not adjusting for account currency — If your account is in EUR or GBP (not USD), pip values need conversion. Our pip value calculator handles this automatically.