Position Sizing for Beginners: How Much Should You Risk Per Trade?

What is position sizing?

Position sizing is the decision of how many shares, or how many lots of a futures or options contract, to trade. Two traders can use the same strategy and take the same entries, and still end up with very different results because they trade different sizes.

Most beginners choose size by feel, or by how much money is in the account. A better approach is to choose it by how much you are prepared to lose if the trade fails.

Why does position size matter more than the entry?

Losing streaks happen to every strategy. If you win about half of your trades, a run of six or more losses in a row becomes likely somewhere in a few hundred trades. Position size decides whether that run is a setback or a disaster.

Here is what ten losses in a row would do to an account, depending on how much is risked on each trade:

• Risking 1 percent per trade: about 90.4 percent of capital is left, a fall of roughly 9.6 percent.
• Risking 2 percent per trade: about 81.7 percent left, a fall of roughly 18.3 percent.
• Risking 5 percent per trade: about 59.9 percent left, a fall of roughly 40.1 percent.
• Risking 10 percent per trade: about 34.9 percent left, a fall of roughly 65.1 percent.

Why is recovering from a big loss so hard?

Losses and gains are not symmetrical. To get back to where you started, a 10 percent loss needs about an 11 percent gain. A 20 percent loss needs a 25 percent gain. A 50 percent loss needs a 100 percent gain, which means doubling the remaining money.

That is why protecting capital comes first. Small losses are easy to recover from. Large ones can end a trading career before your skill has had time to show.

How do you calculate position size?

A worked example: your capital is ₹2,00,000 and you risk 1 percent, which is ₹2,000. You plan to buy a stock at ₹500 with a stop-loss at ₹480, so the risk is ₹20 per share. Divide ₹2,000 by ₹20 and you get 100 shares. The position is worth ₹50,000, a quarter of your capital, but if the stop-loss hits, you lose about ₹2,000 plus charges.

Now suppose the chart tells you the stop-loss belongs at ₹460 instead. The risk is now ₹40 per share, so the quantity drops to 50 shares. A wider stop means a smaller position, not a bigger loss. The rupee risk stays the same.

1. Decide the trading capital you are working with.
2. Choose the percentage you will risk per trade, then convert it to rupees.
3. Decide your entry and stop-loss levels from the chart, not from your wallet.
4. Work out the risk per share: entry price minus stop-loss price.
5. Divide your rupee risk by the risk per share to get the quantity.

How does this work for futures and options?

The idea is the same, except your unit is a lot. Your risk per lot is the difference between entry and exit price multiplied by the lot size. Divide your rupee risk by that number to see how many lots fit. If even one lot risks more than you have decided to lose, the trade is too big for your account. Don't fix that by widening the stop.

Remember that margin is not risk. The margin a broker blocks tells you what you need to hold the position, not what you can lose. Your risk is what you can lose if the trade goes against you, including gaps beyond your stop-loss. Options sellers in particular can lose far more than the premium they collect.

How much should a beginner risk per trade?

Many educators suggest risking a small, fixed fraction of trading capital on any single trade, often 1 to 2 percent. Beginners often start at or below 1 percent while they learn. This is a general educational guideline, not personal advice. The right number depends on your capital, experience and how much loss you can handle emotionally and financially.

It also helps to cap the whole day, for example at three times your per-trade risk, so that a bad morning doesn't turn into a bad month.

If 1 percent of your capital is not enough to trade even one lot of an instrument, that instrument is too large for your account right now. Consider a smaller instrument, or practise with paper trading until your capital grows.

What are the common position-sizing mistakes?

• Sizing up after a win because you feel confident, or after a loss to recover faster.
• Choosing size by feel instead of by the stop-loss distance.
• Moving the stop-loss further away to keep the same quantity.
• Forgetting brokerage, taxes and slippage, which make real losses slightly larger than planned.
• Taking several trades that move together, such as multiple Nifty-linked positions. They act like one large position.
• Using all available margin.

How do you keep yourself honest?

Record your planned risk and your actual risk for every trade. If the actual number is often larger than the plan, you have found a discipline leak, and a journal makes it visible.

The investingg.in trade journal lets you import your tradebook, track P&L, win rate and profit factor, and get discipline feedback on your own trades.