About the Position Size Calculator
Work out how big a trade can be so that hitting your stop loss costs exactly the amount you're willing to lose. Enter your balance and risk, the stop loss, and get the lot size for forex or the number of shares or coins for stocks and crypto.
Lot sizes are rounded down to 0.01, never up, so the real risk is shown next to the result and is never more than you set.
How it works
First the amount at risk is found: your balance times the risk percentage, or a fixed amount you enter. For forex, that amount is divided by the stop loss in pips times the value of one pip on a standard lot of 100,000 units. For stocks and crypto it's divided by the distance between the entry price and the stop.
The value of a pip depends on the pair and your account currency. When the quote currency is your account currency it's simple (EUR/USD: $10 a pip per standard lot). When the base currency is your account currency the pip is divided by the current price, and for other pairs you enter today's rate from the quote currency to your account currency.
Assumptions and limits
- A pip is 0.0001, or 0.01 for pairs quoted in Japanese yen; a standard lot is 100,000 units.
- Spreads, commissions and slippage aren't included; leave a little room for them.
- This is a planning tool, not financial advice. Check your broker's contract sizes.
Worked examples
1% risk on $10,000
With a 50-pip stop on EUR/USD, $100 ÷ (50 × $10) = 0.20 lots.
USD/JPY
At 150.00 a pip on a standard lot is worth $6.67, so $100 with a 30-pip stop is 0.50 lots.
Shares
Risking $500 on a stock bought at $50 with a stop at $48 allows 250 shares.
How to use the Position Size Calculator
- Choose the market. Forex, stocks or crypto.
- Set your risk and stop. Percent of balance or a fixed amount.
- Read the size. Lots, shares or coins to trade.
Frequently asked questions
How do I calculate lot size in forex?
Divide the amount you're willing to lose by the stop loss in pips times the pip value of one standard lot. Risking $100 with a 50-pip stop on EUR/USD gives 100 ÷ (50 × 10) = 0.20 lots.
How much should I risk per trade?
Many traders risk between 0.5% and 2% of their balance on one trade, so a run of losses doesn't wipe out the account. The right figure depends on your strategy and tolerance for losses.
Why is the lot size rounded down?
Most brokers trade in steps of 0.01 lots. Rounding down keeps your loss at the stop within the risk you chose; rounding up could lose more than planned, so the real risk is shown too.
Why do I need an exchange rate for some pairs?
For a pair like EUR/GBP in a US dollar account, a pip is worth a fixed amount of pounds, which must be turned into dollars. Enter today's GBP to USD rate from your broker or a converter.
Does it include spreads and commission?
No. Those depend on your broker and account type. To stay inside your risk, widen the stop by the spread or lower the risk percentage slightly before placing the trade.
This tool runs entirely in your browser. What you enter or upload stays on your device and is never sent to our servers.