If you only learn one thing about trading risk, learn this: the size of your position matters more than the quality of your strategy. A mediocre strategy with disciplined position sizing can compound modest capital for years. A great strategy with reckless position sizing will blow up the same account inside 12 months. The math doesn't care which strategy you used — only how much you risked on each trade.
This article covers the actual math of position sizing. Three real portfolio sizes (₹1 lakh, ₹5 lakh, ₹25 lakh), three concrete examples, and the honest answer to "how much should I risk per trade." If you can't answer that question precisely after reading this, do not place real trades.
The two rules everything depends on
Position sizing is built on two ideas:
- Risk a fixed percentage of your capital per trade. Not a fixed rupee amount. Not "as much as I feel good about." A specific percentage you decided in advance, applied mechanically.
- That percentage determines your position size, given a stop loss. Not the other way around. You don't decide "I want to buy 100 shares of TCS." You decide "I'm willing to risk ₹X. Given my stop is Y rupees away, how many shares does that imply?"
The rest of this article is just consequences of these two rules.
The 1% rule, and why most traders should use 0.5%
The standard rule taught in trading books is the 1% rule: risk no more than 1% of total capital on any single trade. The math behind this:
If you have a 50% win rate strategy with 1.5R average winners, your edge is real but not large. Even disciplined traders with this profile experience losing streaks of 5 to 8 consecutive losses fairly often (statistically, a 50% strategy will produce 8+ consecutive losses several times in any year of trading).
At 1% risk per trade, eight consecutive losses costs you 8% of capital. Recoverable. Painful, not fatal.
At 5% risk per trade, eight consecutive losses costs you 40%. To recover from a 40% drawdown, you need to make 67% on what's left — and most strategies don't produce 67% returns on demand. You're effectively dead money for 18 months.
The 1% rule isn't conservative. It's the math of staying in the game long enough for your edge to express itself.
Now here's the honest version: most retail traders should use 0.5% per trade, not 1%. Three reasons:
- You don't actually know your edge yet. The "50% win rate, 1.5R winners" assumes you have a tested, validated strategy with hundreds of historical trades behind it. Most beginners assume the strategy works because the backtest shows it works — without accounting for slippage, behavioral drift, and regime changes that haven't happened yet.
- Indian retail brokerage and tax costs are higher than the U.S. context most position-sizing books assume. A 0.5% target in India produces similar net-of-cost returns to a 1% target in the U.S. context.
- Drawdowns are emotionally bigger than the math suggests. A 20% drawdown in your trading account feels much worse than a 20% drop in your salary. Most traders quit during their first deep drawdown. Lower per-trade risk reduces the depth of these drawdowns and increases the probability you'll still be trading next year.
In what follows, I'll use 0.5% as the default. Adjust upward to 1% if and only if you have at least 100 verified trades of historical performance, you've survived at least one 20%+ drawdown without panic-quitting, and your backtest plus live results agree to within 30%. If those conditions aren't met, stick with 0.5%.
The position-sizing formula
The math is one formula. Memorize it:
That's the entire framework. Three inputs, one output. Let's walk through what each input means:
- Capital: the total amount in your trading account, including cash. Not your net worth. Not your house. Just the trading account.
- Risk %: the maximum fraction of capital you'll lose if the trade hits the stop. Use 0.005 (0.5%) as default.
- Entry − Stop: the rupee distance from your entry price to your stop-loss price. This is the per-share loss if the stop is hit.
Three concrete examples
Portfolio 1: ₹1 lakh starter account
You're early in your trading journey. You have ₹1 lakh saved up to learn swing trading without affecting your finances if it goes wrong.
Setup: TPB pattern fires on a stock priced at ₹500. Your stop is at ₹475. Per-share risk is ₹25.
You buy 20 shares. Total position cost: 20 × ₹500 = ₹10,000. Maximum risk: 20 × ₹25 = ₹500 (which is 0.5% of ₹1 lakh, as designed).
Now you see the problem at this capital level: your ₹10,000 position is only 10% of your account. If the stock doubles, you make ₹10,000 — a 10% return on the account. That sounds good, but the brokerage and STT round-trip on a ₹10,000 trade in Indian markets is roughly ₹30-50 each side, plus 0.025% STT on sale, plus stamp duty. After costs, your meaningful trade activity is small relative to fixed costs.
Practical advice for ₹1 lakh accounts: trade only 4-6 positions per month, not 15-20. Focus on highest-conviction setups. Use a discount broker (Zerodha, Groww, Upstox) with flat brokerage. Track every trade including all costs. Treat year 1 as paid education, not a profit center.
Portfolio 2: ₹5 lakh active account
You've been trading for 12-18 months. You have a tested strategy. You have ₹5 lakh dedicated to swing trading.
Setup: Darvas Box breakout on a stock priced at ₹800. Stop at ₹760. Per-share risk is ₹40.
You buy 62 shares. Total position cost: 62 × ₹800 = ₹49,600. Maximum risk: 62 × ₹40 = ₹2,480 (~0.5% of capital).
This position is now ~10% of your account — meaningful enough that wins matter, small enough that a stopped-out trade is a regular cost of business, not a catastrophe.
At ₹5 lakh, you can run 5-8 simultaneous positions without overcrowding the account. With 0.5% risk per trade, your maximum total open risk if all stops hit is 2.5-4% — survivable even if every position goes against you simultaneously.
Portfolio 3: ₹25 lakh serious account
Multiple years of experience. Validated strategy. ₹25 lakh allocated to active swing trading.
Setup: VCP breakout on a stock priced at ₹2,400. Stop at ₹2,290. Per-share risk is ₹110.
You buy 113 shares. Total position cost: 113 × ₹2,400 = ₹2,71,200. Maximum risk: 113 × ₹110 = ₹12,430 (~0.5% of capital).
The position is ~11% of capital. With 8-12 simultaneous positions, your account is well-diversified. Total open risk if all stops hit: ~5-6% — still recoverable in a single bad month.
At ₹25 lakh, you can comfortably run 8-15 simultaneous positions across multiple strategies. This is the capital level where running TPB + Darvas + VCP + Williams %R simultaneously starts being meaningful — you have enough capital that each strategy gets a real allocation, and enough trades that statistical edge has time to express itself.
The three mistakes that destroy position sizing
Mistake 1: Ignoring stop distance
A common error: "I want to buy 100 shares of TCS, my account can afford it." This ignores the stop distance. If TCS is at ₹3,800 and your stop is at ₹3,500, your per-share risk is ₹300. Buying 100 shares means risking ₹30,000 — which is 6% of a ₹5 lakh account, far above the 0.5% target.
The stop distance, not the share count, must drive the position size. A wide stop means fewer shares. A tight stop means more shares. The risk percentage stays constant.
Mistake 2: "Averaging down"
The trade goes against you. You think "the stock is even cheaper now, I'll buy more." Adding to a losing position turns a 0.5% planned loss into a 1.5% or 2% actual loss. Over time, this destroys disciplined position sizing.
The disciplined version: when a trade hits its stop, you're out. If a new setup forms later, you can re-enter as a new trade with fresh sizing math — but never add to an existing loser.
Mistake 3: Using leverage to "fix" small accounts
"I have ₹50,000 but my broker offers 5x intraday margin, so I can take ₹2.5 lakh positions." This isn't fixing the capital problem; it's amplifying every loss by 5x. A 5% adverse move — routine in markets — destroys the entire account.
If your capital is too small for swing trading at honest position sizes, the answer is to build the capital base first, not to use leverage to simulate having more.
Multiple positions: the correlation question
If you have 5 open positions, each at 0.5% risk, your total open risk is 2.5% — assuming positions are uncorrelated. But if all 5 positions are in the same sector (say, banking stocks during an RBI policy week), they tend to move together. A bad sector day can hit all 5 stops simultaneously.
Practical rule: treat positions in the same sector as roughly half-correlated. Five banking stocks at 0.5% each behave more like 2.5% on a single trade than 0.5% × 5 = 2.5% spread evenly. Adjust by reducing per-position risk when you have sector concentration, or by capping the number of positions per sector.
A simple sector concentration rule: maximum 2-3 simultaneous positions in any single sector. If 4 banking stocks all give buy signals at once, take the strongest 2-3 and pass on the others.
What this means for you
Position sizing is the most boring topic in trading and the most important. You can have a brilliant strategy and lose money. You cannot have disciplined position sizing and blow up an account — the math literally prevents it.
Take the position-sizing formula, write it down, tape it to your monitor. Before every trade, calculate three numbers: capital, risk %, stop distance. Do the division. Buy that exact number of shares. No "rounding up because it feels right." No "this one looks special, let me size up." Mechanical execution.
The next article in this series goes deeper on the stop-loss side of the equation: how to place stops that survive normal volatility but exit when the trade thesis is wrong. Stop placement is the other half of the position-sizing equation — the formula assumes you know where your stop is, and bad stops destroy good sizing.