Position size calculator
Work out how many lots, contracts or shares to trade from your account size, your risk and your stop loss.
Why position size matters more than your entry
Two traders can take the same setup, with the same entry and the same stop, and end the year in very different places. The difference is usually how much each of them risked.
Position sizing turns your stop loss into a planned, fixed loss. When every losing trade costs about the same small share of your account, a bad week stays a bad week instead of becoming a blown account.
It also keeps you honest. If the size that fits your risk is smaller than you hoped, the trade or the stop needs rethinking, not your risk.
What a losing streak does at different risk levels
Every strategy has losing streaks. Ten losses in a row is rare, but across hundreds of trades it is closer than most traders expect.
Recovery is always harder than the fall: a 10% drawdown needs an 11% gain to get back to where you were, a 25% drawdown needs 33%, and a 50% drawdown needs 100%.
How the position size calculator works
Every market comes down to one formula: position size equals the amount you are willing to lose, divided by your stop distance times the value of one point for one unit.
The amount at risk is your account size times the percentage you choose, or a fixed amount. The stop distance is how far price can move against you before you are out: pips in forex, ticks or points in futures, points of premium in options.
The calculator rounds down to a size your broker accepts, so the real risk is never more than you planned.
Worked examples for forex, futures, Nifty F&O and crypto
Each example risks 1% of the account on one trade.
How much should you risk per trade?
Many professional traders risk between 0.5% and 2% of their account on a single trade. 1% is a common starting point: small enough to survive a long losing streak, large enough for winners to matter.
Risk less while you learn a new setup, after a run of losses, or when several open positions move together. Three long trades on Nifty, Bank Nifty and Fin Nifty are closer to one large trade than three small ones.
Set a weekly loss limit as well. Stopping for the week after losing, say, 4% protects you on the days your judgement is at its worst.
What the calculator cannot see
The result is an estimate for educational purposes. Spreads, brokerage, exchange fees, taxes such as STT, slippage and price gaps all add to the real cost of a losing trade, and contract and lot sizes vary by broker and change when exchanges revise them.
Leave some room for these, especially in fast markets and around news, and confirm contract details with your broker before you trade.
From one trade to a process
A calculator sizes one trade. A trading journal shows whether you stick to your risk across hundreds of them. LYT logs every trade, checks your risk per trade against your plan, and warns you when you reach your weekly loss limit.
Frequently asked questions
What is position sizing in trading?
Position sizing is deciding how many lots, contracts or shares to trade so that, if your stop loss is hit, you lose a planned amount of your account, usually between 0.5% and 2%.
How do I calculate lot size in forex?
Divide the amount you are willing to lose by your stop loss in pips times the pip value of one standard lot. On EUR/USD a standard lot is worth about $10 a pip, so risking $100 with a 25-pip stop gives 0.40 lots.
How many Nifty option lots should I trade?
Multiply your stop loss in premium points by the Nifty lot size (65 units) to get the loss per lot, then divide your risk amount by it. With ₹5,000 of risk and a 20-point stop, that is 3 lots.
Does the calculator include brokerage, spreads and slippage?
No. It sizes the trade from your stop loss alone, so treat the result as an approximate maximum and leave room for spreads, brokerage, taxes and slippage.
What is a good risk per trade for beginners?
Start at 0.5% to 1% of your account per trade. That lets you survive the losing streaks every trader goes through while you learn what your strategy really does.
Is this position size calculator free?
Yes. It is free to use without an account and works for forex, gold and silver, crypto, US index and commodity futures, and Indian stocks, options and futures.