Forex Lot Size Calculator
Calculate the correct lot size for forex trades based on account balance, risk percentage, and stop loss in pips.
Supports standard, mini, and micro lots.
In Forex trading, a “lot” is a standardized unit of currency. The lot size you trade directly determines how much money you make or lose per pip of price movement. Calculating the correct lot size is essential for disciplined risk management.
Lot Size Types:
| Lot Type | Units of Base Currency | Pip Value (USD pairs) |
|---|---|---|
| Standard lot | 100,000 | ~$10 per pip |
| Mini lot | 10,000 | ~$1 per pip |
| Micro lot | 1,000 | ~$0.10 per pip |
| Nano lot | 100 | ~$0.01 per pip |
The Risk-Based Lot Size Formula:
Lot Size = (Account Balance × Risk %) / (Stop Loss in pips × Pip Value per standard lot)
Worked Example:
- Account balance: $10,000
- Risk per trade: 1% = $100
- Stop loss: 50 pips
- Trading EUR/USD (pip value = $10 per standard lot)
Lot Size = $100 / (50 × $10) = $100 / $500 = 0.2 lots (2 mini lots)
If price hits stop loss: loss = 50 pips × $1/pip × 2 mini lots = $100 ✓
Pip Value Formula for Cross Pairs:
Pip Value = (0.0001 / Exchange Rate) × Lot Size × 100,000
For USD/JPY at 150.00: Pip Value = (0.01 / 150.00) × 100,000 = $6.67 per standard lot
Practical Tips:
- Never risk more than 1–2% of account per trade
- Always calculate lot size before entering a trade — never guess
- Pip value changes with the exchange rate for non-USD quote currencies
- Leverage amplifies both gains and losses — higher lot sizes magnify risk dramatically