How Much Should You Risk on a Single Trade?
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Table of contents7
30-second summary
- The rule
- Fix your loss before you buy
- Common limit
- 1-2% of the account
- Formula
- Risk ÷ (entry − stop)
- Decided by
- Arithmetic, not conviction
Decide the most you are willing to lose on a trade before you place it, as a fixed percentage of your account — commonly 1% or 2%. Position size then follows from arithmetic: divide that rupee amount by the distance between your entry price and your stop price.
Key takeaways
- Choose the rupee amount you are willing to lose before entering, never after.
- Position size is the output of a calculation, not a feeling about the trade.
- A wider stop means a smaller position, so total risk stays constant.
- The whole method depends on actually honouring the stop.
Why decide the loss first?
Most beginners decide how much to buy and then discover what they stand to lose. That is backwards. The amount you can lose is the one part of a trade you control completely — the price is not up to you, but the size of your bet is.
Fixing the loss first turns an emotional decision into an arithmetic one. You are no longer asking “how confident am I?”, which is a feeling that tends to peak at exactly the wrong moments. You are asking “what does my rule allow?”
The one rule
Before entering any trade, decide the maximum amount of your account you are willing to lose on it. Most people express this as a fixed percentage — commonly 1% or 2%.
The percentage matters less than the fact that it never changes. A fixed fraction means your position shrinks automatically after losses and grows again as the account recovers, without you having to decide anything in the moment.
Working out the position size
Three inputs, one division. These are invented round numbers used to make the arithmetic visible:
| Input | Example value |
|---|---|
| Account size | 1,00,000 |
| Risk per trade | 1% = 1,000 |
| Entry price | 500 |
| Stop price | 475 |
| Risk per share (entry−stop) | 25 |
| Shares to buy | 1,000 ÷ 25 = 40 |
Read from the top, it is three steps:
- Your account₹1,00,000Everything you have to trade with.
- Most you let yourself lose₹1,0001% of the account. This number is the rule — it does not change from trade to trade.
- Shares you buy40₹1,000 ÷ ₹25 per share. Always round down.
Money you put in
₹20,000
40 shares × ₹500
Money you can lose
₹1,000
40 shares × ₹25 to the stop
These are two different numbers. Mixing them up is the most common beginner mistake — you commit ₹20,000, but only ₹1,000 is at risk, because you leave before the rest is gone.
If the division does not come out even, always round down. Rounding up quietly breaks the one rule the whole method exists to enforce — you would be risking more than the limit you set for yourself, which defeats the point.
One more rule worth stating plainly: the stop must sit below your entry. A stop at or above the price you paid means there is no defined loss to work from, so there is no size to calculate.
Why a wider stop means a smaller position
This is the part that surprises people. Keep everything else the same and move the stop further away:
Stop at ₹475
₹25 per share
Stop at ₹450
₹50 per share
Stop at ₹400
₹100 per share
The loss never changes. In every row above you still lose ₹1,000 if the stop is hit. The further away the stop, the fewer shares you buy — so the risk stays put while the position shrinks.
Think of it like standing back from a ledge. The further away your exit, the less you can afford to carry. The position adjusts so the risk does not. That is the entire point: the stop decides the size, and the size keeps the risk fixed.
Where this breaks down
Three honest limits, none of them optional reading:
- It only works if you honour the stop. A rule you override is not a rule. This method has no protection whatsoever against a trader who moves the stop lower to avoid taking a loss.
- Gaps ignore your stop. If a price opens far below your stop, you exit at whatever the market offers, not at your number. The planned loss is a floor on your intention, not a guarantee.
- It says nothing about whether the trade is any good. Sizing controls the damage from being wrong. It does not make you right, and correct sizing on a long run of poor decisions still ends badly.
How this was calculated
This article contains no market data. Every figure is an invented round number chosen to make the arithmetic easy to follow, and is labelled as an example in the text. No security is named and no outcome is claimed.
Sources
- Framework reference on this site: Fixed-Fractional Position Sizing
- Van K. Tharp, Trade Your Way to Financial Freedom (1998)
Frequently asked questions
What does "risk 1% per trade" actually mean?
It means that if the trade goes against you and your stop is hit, you lose 1% of your total account, not 1% of the position. On an account of 1,00,000 rupees, that is 1,000 rupees lost — regardless of whether you bought 10 shares or 500.
How do I work out the number of shares?
Divide the rupee amount you are willing to risk by the per-share distance between your entry and your stop. If you accept a 1,000 rupee loss and your stop sits 25 rupees below entry, you buy 40 shares, because 40 multiplied by 25 equals 1,000.
What if the calculation says I can only buy two shares?
That is the method working, not failing. A tiny position size is telling you the stop is too far from the entry for your account. Either find an entry closer to a sensible stop, or skip the trade.
Does this guarantee I will not lose much?
No. It bounds the loss on each trade you exit at your stop, but nothing prevents a run of consecutive losses, and a price gap can jump straight past your stop so the actual loss is larger than planned.
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