What is the position size formula?

Units = money at risk ÷ (entry − stop). Money at risk is your account times your risk per trade, for example 1%.

How do I size a crypto trade with leverage?

Use the same formula for the size. Leverage only changes how much margin you post. Keep the liquidation price well beyond your stop.

How many lots should I trade?

Divide the money you are willing to lose by the loss per lot at your stop, then round down. Check the lot size first.

Does the calculator include charges?

Yes. The TradingCheckup Trade Planner adds the charges for Indian F&O, shares, futures, forex and crypto so the loss at your stop is shown after costs.

Should I size by the amount of money or by the stop?

By the stop. Decide the loss you accept, then divide by the distance to the stop. Sizing by a fixed amount of money makes the risk change with every trade.

Guide · risk and sizing

Position size calculator: shares and crypto

Position size answers one question: how much do I buy so that, if my stop is hit, I lose only the amount I decided? It is one line of maths.

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The formula

Position size (units) = money at risk ÷ (entry price − stop price)

Money at risk = account x your risk per trade (for example 1%).

Example 1: shares

Account ₹2,00,000. Risk 1% = ₹2,000. Buy at ₹500, stop at ₹490 (₹10 away).

Size = ₹2,000 ÷ ₹10 = 200 shares, a ₹1,00,000 position. You are using half the account, but you only lose about ₹2,000 (plus charges) if the stop is hit.

Example 2: Bitcoin

Account $5,000. Risk 1% = $50. Buy at $60,000, stop at $58,800 (2% below).

Size = $50 ÷ $1,200 = 0.0417 BTC, about a $2,500 position. Add the exchange fee (around 0.1% per side on spot, so about $5 for the round trip) to the planned loss.

Example 3: index futures or options lots

When you can only buy whole lots, divide by the money per lot instead. Account ₹5,00,000, risk 1% = ₹5,000. A NIFTY option bought at ₹120 with a stop at ₹100 risks 20 points x 65 units = ₹1,300 per lot. ₹5,000 ÷ ₹1,300 = 3.8, so 3 lots (always round down).

Example 4: short trades

Same formula with the stop above the entry. Short at $100, stop $104, risk $200 → 50 shares.

Common mistakes

Putting the stop where the size fits. Choose the stop from the chart first, then the size. Never move the stop to buy more.
Forgetting leverage. With 10x leverage the size formula is the same, but your margin is smaller. A liquidation can close you before your stop.
Ignoring a normal bad day. If the stop is closer than an ordinary daily move, you will be stopped by noise. Check how big a bad day is for that market first.
Forgetting charges and slippage. In Indian F&O, one futures lot round trip can cost several hundred rupees in charges.
Rounding up. Always round lots and units down.

When the position is bigger than your account

If the formula asks for more than you have (a very tight stop), either accept a smaller size (and a smaller risk) or skip the trade. Using margin to reach the size adds the risk of gaps and liquidation.

Fixed size vs fixed risk

Many traders buy the same amount every time - say ₹50,000 of any share. That makes the risk different on every trade: a share with a 2% stop risks ₹1,000, one with a 10% stop risks ₹5,000. Sizing from the stop keeps the loss the same and the position changes instead. Over many trades, fixed risk keeps one wide-stop trade from doing the damage of five normal ones.

A quick checklist before you click buy

Stop chosen from the chart, not from the size
Stop further away than a normal bad day for that market
Money at risk = account x your risk %
Units = money at risk ÷ stop distance, rounded down
Charges and slippage added
Position value fits your account without borrowing you do not want

What changes in forex and futures

In forex and futures you trade in lots or contracts, each worth a fixed amount per point (or pip). The formula is the same, but you divide by the money lost per lot at your stop: for a Micro E-mini S&P 500 contract worth $5 a point, a 10-point stop risks $50 per contract, so $200 at risk allows 4 contracts. For a standard forex lot of 100,000 units, a 20-pip stop on EUR/USD risks about $200 per lot.

General information about the past and about your own numbers. Not financial advice and not a recommendation. It does not consider your goals or situation.

Frequently asked questions

What is the position size formula?: Units = money at risk ÷ (entry − stop). Money at risk is your account times your risk per trade, for example 1%.
How do I size a crypto trade with leverage?: Use the same formula for the size. Leverage only changes how much margin you post. Keep the liquidation price well beyond your stop.
How many lots should I trade?: Divide the money you are willing to lose by the loss per lot at your stop, then round down. Check the lot size first.
Does the calculator include charges?: Yes. The TradingCheckup Trade Planner adds the charges for Indian F&O, shares, futures, forex and crypto so the loss at your stop is shown after costs.
Should I size by the amount of money or by the stop?: By the stop. Decide the loss you accept, then divide by the distance to the stop. Sizing by a fixed amount of money makes the risk change with every trade.

Size your next trade

Shares, crypto, futures, forex and Indian F&O. The planner rounds to real lots and adds the costs.

Open the position size calculator (free)

Keep reading

NIFTY and BANK NIFTY lot size and chargesLot sizes, what one trade costs, and a worked example in rupees.How much to risk per tradeThe 1% idea, losing streaks in numbers, and how to choose your own limit.How big is a bad day for a share?Our 1-in-10 bad-day range, how it works and how it was tested.

All guides →