Lot Size Calculator
Calculate the correct lot size for any forex trade based on your account balance, risk tolerance, and stop loss distance in pips.
Free — no signup, no ads, instant results
Inputs
Results
Risk Amount
$100.00
Standard Lots
0.20
Mini Lots
2.00
Micro Lots
20.00
Units
20,000
Who Is This For?
Forex traders who need to determine the correct lot size based on their account balance, risk percentage, and stop loss distance in pips.
Understanding Forex Lot Sizes
In forex, a standard lot is 100,000 units of the base currency, a mini lot is 10,000, and a micro lot is 1,000. Choosing the right lot size ensures you never risk more than your plan allows on a single trade.
The standard rule: risk 1-2% of your account per trade. This calculator converts that percentage into the exact lot size based on your stop loss distance. A wider stop loss means a smaller lot size, and vice versa.
Use this alongside our position size calculator for non-forex markets, and track your results in the free trading journal.
Lot Size Formula
The formula is: Lot Size = (Account Balance × Risk %) / (Stop Loss in Pips × Pip Value per Standard Lot)
Example: $10,000 account, 1% risk ($100), 30-pip stop on EUR/USD. Pip value = $10/standard lot. Lot size = $100 / (30 × $10) = 0.33 lots (3.3 mini lots)
For JPY pairs, adjust the pip value calculation since 1 pip = 0.01 instead of 0.0001.
Lot Size Reference Table
Standard Lot (1.0): 100,000 units, $10/pip on USD pairs. Suitable for accounts $10,000 and above.
Mini Lot (0.1): 10,000 units, $1/pip. Suitable for accounts $1,000 to $10,000.
Micro Lot (0.01): 1,000 units, $0.10/pip. Suitable for accounts under $1,000 or very tight stops.
The lot size you use should be determined by your risk per trade, not your account size alone.
Worked Example
Account balance: $10,000
Risk per trade: 1% = $100
Stop loss: 50 pips
Pair: EUR/USD (pip value $10/std lot)
Lot size: $100 / (50 × $10) = 0.20 lots (2 mini lots)
Assumptions & Edge Cases
- Pip values are approximate and depend on current exchange rates.
- Does not account for commission in risk calculation.
- Standard lot = 100,000 units, mini = 10,000, micro = 1,000.
Related Reading
Frequently Asked Questions
Your lot size should be determined by your risk management rules, not chosen arbitrarily. Calculate it from your account balance, the percentage you want to risk per trade, and the distance to your stop loss in pips. A $5,000 account risking 1% with a 25-pip stop on EUR/USD should use 0.2 standard lots (2 mini lots).
A standard lot is 100,000 units of the base currency and has a pip value of approximately $10 on USD-quoted pairs. A mini lot is 10,000 units ($1/pip), and a micro lot is 1,000 units ($0.10/pip). The lot type affects your pip value and therefore your dollar risk per trade.
Multiply the lot size by the lot unit value. 0.5 standard lots = 50,000 units. 3 mini lots = 30,000 units. In most trading platforms, you enter position size in lots, and the platform converts to units internally. This calculator handles the conversion automatically.