Forex Lot Size Calculator
Enter your risk percentage and stop distance in pips to get the lot size for a currency pair, rounded down to a size a broker will fill.
Lot size, in standard lots
0.16
Actual risk $48.00
Lot size, in standard lots
0.16
Actual risk $48.00
- Risk budget
- $50.00
- Actual risk after rounding down
- $48.00
- Units of currency
- 16,000
- Mini lots
- 1.6
- Micro lots
- 16
- Pip value per standard lot
- $10.00
How to calculate forex lot size
Lot size turns a risk budget into a trade size. Divide the money you will risk by the stop distance in pips and the pip value of a standard lot, and the answer is in standard lots.
This calculator works out the pip value from the pair you pick, which is why a yen or pound pair asks for a rate. It rounds down to 0.01 lots, the smallest step many brokers offer, and shows the real risk at that size.
Lots = (account × risk %) ÷ (stop pips × pip value per standard lot).
Worked example
On a $5,000 account at 1% risk, your budget is $50. A 30 pip stop on EUR/USD at $10 a pip costs $300 per standard lot, so the exact size is 0.1667 lots.
Rounded down, that is 0.16 lots, or 16,000 units, and the actual risk is $48.
What the result does not account for
- Your broker's margin requirement and minimum trade size, which this calculator does not check.
- Spread, slippage and gaps over a weekend, which can make a loss larger than planned.
- Swap charges on trades held overnight.
Frequently asked questions
What is a lot in forex trading?
A standard lot is 100,000 units of the base currency, a mini lot is 10,000 and a micro lot is 1,000. The lot size sets how much each pip is worth.
How do I know if a trade is too large for my account?
Multiply the stop in pips by the pip value and the lots, then divide by your account balance. That is the share of your account the trade risks, and this calculator works backward from the share you choose.
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