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Position size calculator
How many lots can you trade so that a stop-loss hit costs exactly the risk you planned? Enter your balance, risk per trade and stop distance. The calculator converts pips or points into your account currency and rounds down to your broker's lot step, so the risk is never exceeded.
- Risk amount
- $100.00
- Loss at the stop
- $100.00
Loss per 1.00 lot at the stop: $250.00
Exact size 0.4000 lots, rounded down to the lot step.
Estimate without commission and swap.
The formula behind it
Position size = (balance × risk %) ÷ (loss of one lot at the stop). The risk amount is the easy part: 1% of $10,000 is $100.
What one lot loses at the stop depends on the instrument. In forex, one standard lot is 100,000 units of the base currency and one pip is 0.0001 (0.01 for yen pairs). For gold, one lot is usually 100 ounces, so a $1 move is $100 per lot. For indices, your broker sets the value per point.
If the pair is not quoted in your account currency, the loss is converted at the current exchange rate. That is why USDJPY or EURGBP need a price or rate as an extra input.
Example: $10,000 account, 1% risk, 25-pip stop on EURUSD
The risk is $100. On EURUSD one pip is worth $10 per standard lot, so 25 pips cost $250 per lot. $100 ÷ $250 = 0.40 lots.
With a 35-pip stop the result is 0.2857 lots. The calculator rounds down to 0.28, so a stop-loss hit costs $98 instead of slightly more than $100.
Common mistakes
- Using the same lot size for every trade. A wider stop with the same lot size means a bigger loss.
- Mixing up pips and points. Many brokers quote five decimals, so 10 points are one pip.
- Assuming every gold or index contract is the same. MT5 shows the contract size in the symbol specification.
- Rounding up. If the exact size is 0.287 lots, 0.29 lots already risk more than planned.
ProRisk Manager for MT5
In MT5 the lot size follows your stop
Doing this math before every trade is slow and easy to get wrong. ProRisk Manager does it in MetaTrader 5: you set your risk in percent, drag the stop-loss line on the chart, and the panel shows the matching lot size, calculated with your broker's symbol data. The EA places the stop loss as well and can move it to breakeven.
- 14 days PRO, no payment details
- Test on a demo account first
- Ends by itself
Start your 14-day PRO trial
Frequently asked questions
What lot size should I use for 1% risk?
It depends on the stop distance. With a $10,000 account and a 25-pip stop on EURUSD it is 0.40 lots, with a 50-pip stop 0.20 lots. The wider the stop, the smaller the position.
How much is one pip worth?
On pairs quoted in US dollars, such as EURUSD or GBPUSD, one pip is worth $10 per standard lot, $1 per mini lot (0.10) and $0.10 per micro lot (0.01). On other pairs the value depends on the exchange rate.
How do I calculate the lot size for gold (XAUUSD)?
Multiply the stop distance in dollars by the contract size. With 100 ounces per lot, a $5 stop costs $500 per lot, so 1% of a $100,000 account ($1,000) allows 2.00 lots. Check your broker's contract size; it is not always 100.
Why does the result differ from my broker's calculator?
Usually because of the exchange rate, the contract size or rounding. This calculator rounds down to the lot step so you never risk more than planned. Commission and swap are not included.
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- Trailing stop EA for MT5Breakeven and trailing in steps of your risk.
- MT5 trade managers comparedFour risk tools side by side, with sources.
The results are estimates based on your inputs. Check your prop firm's rules and your broker's contract specifications before you trade. Not financial advice. Trading involves risk.