Getting position size right is the single most important risk-management habit in trading. This free lot size calculator turns your account balance, the percentage you're willing to risk, and your stop-loss distance into a precise position size in lots — so one losing trade never costs more than you planned.
Position size calculator
Forex lot size
Assumes the pip value per standard lot in your account currency (≈10 for USD-quoted majors).
How it works
lots = (balance × risk%) ÷ (stop-loss pips × pip value per standard lot)
First it works out your risk amount (balance × risk%). Then it divides that by the cash you'd lose per lot if the stop is hit (stop-loss pips × pip value per lot). The result is how many lots keep your loss at exactly your chosen risk. The pip value per standard lot is about 10 in your account currency for USD-quoted majors — use our pip calculator for other cases.
Worked example
- Balance $5,000, risk 1% → risk amount = $50.
- Stop loss 20 pips, pip value $10/lot → loss per lot = $200.
- Position size = 50 ÷ 200 = 0.25 lots.
Correct position sizing caps the loss on any single trade, but trading is still high-risk and most retail traders lose money. This is a tool, not financial advice. Practise on a demo first.
Put it into practice on a free demo
Open a free MT4 demo and trade your calculated lot sizes with virtual money before risking real funds.
⚠ Trading forex and CFDs is high-risk and most retail traders lose money. This is not financial advice.
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Related tools & guides
Pair it with the pip calculator and margin calculator, or learn how to use MT4.
Frequently asked questions
What is position sizing?
Position sizing is choosing how large a trade to place so that, if your stop loss is hit, you only lose a planned amount — usually a small percentage of your account. It's the core of risk management and matters more than any indicator.
How do I calculate lot size?
Lot size = (account balance × risk %) ÷ (stop-loss in pips × pip value per standard lot). For example, risking 1% of a $5,000 account on a 20-pip stop, with a $10 pip value, gives 0.25 lots.
How much should I risk per trade?
Many traders cap risk at around 1–2% of their account per trade, so a losing streak doesn't do lasting damage. This is a common rule of thumb, not advice — the right figure depends on your circumstances and risk tolerance.
What is a lot in forex?
A lot is a standardised trade size. A standard lot is 100,000 units of the base currency, a mini lot 10,000, and a micro lot 1,000. Smaller lots let you size positions precisely and keep risk small while learning.
Trading foreign exchange and contracts for difference (CFDs) carries a high level of risk and may not be suitable for all investors. Leverage can work against you as well as for you. You could lose some or all of your deposited funds; do not trade with money you cannot afford to lose. Past performance is not indicative of future results. Nothing on MT4Download.com is financial, investment, or trading advice. Consider your circumstances and seek independent advice if needed.