A forex position size calculator tells you exactly how many lots to trade so a losing trade never costs more than you intended. Instead of guessing your trade size, you set your account balance, the percentage you’re willing to risk, and your stop loss in pips, and the calculator works out the precise position size that keeps your loss inside that limit. It’s the simplest way to apply proper risk management on every trade, and it works for major currency pairs across any account size.
Never risk more than you mean to. Enter your account, your risk per trade, and your stop loss to get the exact lot size in seconds.
How to use it
- Set your account currency and balance so the numbers come out in money you actually hold.
- Choose how much you're willing to lose on this trade. The 1% rule is the standard starting point: risk no more than 1% of your account on any single position.
- Enter your stop loss in pips — the distance from your entry to where you'd admit the trade is wrong.
- Pick your pair. The calculator returns the exact lot size that keeps your loss at your chosen limit if the stop is hit.
Why position sizing matters more than entries
Most traders blow up accounts not because their entries are bad, but because their size is wrong. One oversized trade with a wide stop can erase weeks of gains.
Position sizing flips that around. You decide the loss first, then the tool works backwards to the lot size that respects it. Your downside is fixed before you ever click buy, which is exactly how disciplined traders survive long enough to let their edge play out.
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Disclaimer: This calculator is for educational and informational purposes only and is not financial or investment advice. Forex trading carries a high level of risk. Pip values for USD-based and non-USD accounts depend on live exchange rates and your broker's contract specifications — always confirm with your broker before trading. You are solely responsible for your trading decisions.
Frequently Asked Questions.
What is a position size calculator and why should I use it?
It’s a risk management tool that works out the exact trade size in lots based on your account balance, how much you’re willing to risk, and your stop loss. It matters because most trading accounts are lost to oversized trades, not bad entries. By fixing your loss before you enter, you stay in the game long enough for your strategy to work.
How much of my account should I risk per trade?
A common guideline is the 1% rule: risk no more than 1% of your account on any single trade. Some traders go up to 2%. Keeping risk small means a losing streak can’t wipe you out, and the calculator turns your chosen percentage into an exact lot size automatically.
How is position size calculated?
The calculator takes the money you’re risking (your balance multiplied by your risk percentage) and divides it by your stop loss in pips multiplied by the pip value for your pair. The result is the number of lots that puts exactly your chosen amount at risk if the stop is hit.
Does the currency pair change the calculation?
Yes. Pip value differs by pair. For pairs quoted in your account currency, like EUR/USD on a US dollar account, the pip value is fixed. For pairs where your account currency is the base, like USD/JPY, the pip value depends on the current exchange rate, which is why the calculator asks for the pair’s price on those.
Is this position size calculator free to use?
Yes, it’s completely free with no signup. Enter your numbers and the lot size updates instantly, right in your browser.