Lot Size Calculator (Forex Position Size Calculator)

Lot Size Calculator (Position Size Calculator)

Work out how many lots to trade so that hitting your stop loss costs exactly the amount you planned to risk. Choose your account currency, the pair, your risk and your stop distance: the calculator converts the pip value for you.

Risk warning: This content is for educational purposes only and not financial advice. Forex trading involves risk, and you can lose money.

Your trade

Account currency

Account balance

Risk per trade (% of balance)

or risk amount (overrides %)

Currency pair

Stop loss (pips)

Result

Position size

Units, mini and micro lots

Amount at risk

Pip value per 1.00 lot

Standard lot = 100,000 units. The size is rounded down to 0.01 lots, so you never risk more than planned. Check your broker's contract size.

How the calculation works

The calculator uses the standard position sizing formula:

Lots = risk amount ÷ (stop loss in pips × pip value per 1.00 lot)

Pip value: 1 pip on a standard lot (100,000 units) is worth 10 units of the quote currency, or 1,000 yen on JPY pairs.
Conversion: if the quote currency is not your account currency, the pip value is converted with the current exchange rate. That is the extra price the calculator asks for.
Rounding: the result is rounded down to 0.01 lots, the smallest size most brokers allow.

Example

You have a USD account of $2,000 and risk 1% per trade, so $20. You buy EUR/USD with a stop loss 25 pips away. One standard lot of EUR/USD is worth $10 per pip.

$20 ÷ (25 × $10) = 0.08 lots. If the stop is hit, you lose about $20 plus costs, whatever the pair does.

Common mistakes

Choosing the lot size first: then adjusting the stop to fit. The stop belongs where your idea is wrong.
Forgetting costs: spread and commission add a little to every loss.
Ignoring slippage and gaps: in fast markets a stop can fill worse than planned.
Rounding up: always round down when you are between two sizes.

Lot size calculator: frequently asked questions

What lot size should I use with $100?

With $100 and 1% risk you can lose $1 per trade. With a 20-pip stop on EUR/USD that is 0.005 lots, below the 0.01 minimum. That is why very small accounts struggle: you either risk more than 1% or need a tighter stop.

Is one lot always worth $10 per pip?

Only when the quote currency is the US dollar and your account is in dollars, as with EUR/USD or GBP/USD. On other pairs, or with another account currency, the pip value is converted. The calculator does this for you.

Is a lot size calculator the same as a position size calculator?

Yes. Both tell you how big your position should be for a given risk and stop loss. Forex traders usually express the answer in lots.