Risk Management: Position Sizing and the 1% Rule

What risk management means in practice

Risk management is not an attitude. It is a number you work out before opening a position: the amount this trade can take from your account if it goes wrong.

Three things set that number, and you control all three:

1. The distance to your stop-loss, in pips.
2. The size of the position, in lots.
3. The value of one pip at that size, which comes from the instrument.

Multiply the stop distance by the pip value and you have the cost of being wrong.

Notice what is absent: your opinion about where price is going, and leverage. A trader who is right more often than not, but sizes without a limit, can still empty an account.

The 1% rule: how much to risk on a single trade

The 1% rule says no single trade should be able to cost you more than 1% of your account balance. On a $2,000 account that is $20. That is the maximum loss if the stop-loss is hit, decided before you place the order.

It is a percentage rather than a fixed sum for a reason: the amount at stake moves with the account. If the balance falls to $1,800, the figure falls to $18 on its own, without you deciding anything while you are already down.

Some traders use 0.5%, some 2%. The figure matters less than having one, writing it down, and not changing it because a trade feels more certain than the last. The trades that feel most certain are not a separate category with different arithmetic.

One hard limit is worth knowing. The smallest position most retail accounts can open is 0.01 lots, so on a small balance with a wide stop, the size the rule calls for can be smaller than that minimum. Then the rule cannot be followed as written, and that should be a conscious decision rather than an accident.

How to calculate position size step by step

The formula:

Position size in lots = Risk in money ÷ (Stop distance in pips × pip value per lot)

In six steps:

1. Take your risk in money. Balance × 1%.
2. Decide where the stop-loss goes from the chart: below the level that would show a long was wrong, above it for a short.
3. Measure the stop distance in pips from your entry to that level.
4. Look up the pip value per lot for the instrument.
5. Divide. Risk in money ÷ (stop distance × pip value per lot).
6. Round down to the nearest step your account allows, normally 0.01 lots. Always down: rounding up puts you over your own limit.

Step 4 matters because a pip is worth a different amount on each instrument. Pips, lots and contract size explains where these come from.

Index CFDs such as the US 500 are quoted in index points, and a point’s value depends on the contract size, so check the specification first.

The order of the steps is what people get wrong. The stop goes where the chart says, then the size is calculated to fit it. Moving a stop closer so you can trade a bigger size does not reduce risk; it makes the position more likely to be closed.

Worked example: sizing a trade on a $2,000 account

Your balance is $2,000, so under the 1% rule this trade may cost at most $20.

You want to buy EUR/USD. The ask is 1.0800, and the level that would show the idea has failed sits at 1.0770, so the stop-loss goes there.

Step 1 — risk in money. $2,000 × 1% = $20.

Steps 2 and 3 — stop distance. 1.0800 − 1.0770 = 0.0030, or 30 pips.

Step 4 — pip value. On EUR/USD, one pip on 1.00 lot is $10.

Step 5 — divide. A 30-pip stop on 1.00 lot costs 30 × $10 = $300, so:

$20 ÷ $300 = 0.0667 lots

Step 6 — round down. To the nearest 0.01, that is 0.06 lots.

Check it. At 0.06 lots, one pip is worth $0.60, so a 30-pip stop costs 30 × $0.60 = $18.00, inside your $20 limit. Rounding up to 0.07 lots puts a pip at $0.70 and the stop at $21.00, over it.

Add the spread. A long is closed on the bid, so the real distance from your fill to your stop is 30 pips plus the spread. With a typical one-pip spread that is 31 pips, and being stopped out costs about $18.60. The balance would go from $2,000 to about $1,981.40, and 1% of that is about $19.81: the rule adjusts itself. A take-profit 60 pips the other way closes the same 0.06 lots at the same $0.60 per pip.

If the stop belongs further away. Suppose the level is 1.0740 instead, a 60-pip stop. The risk budget is unchanged:

$20 ÷ (60 × $10) = 0.0333 lots → 0.03 lots

A stop twice as wide gives a position roughly half the size, and the cost of being wrong stays near $20. The stop distance sets the size. The size never sets the stop.

If the answer is smaller than 0.01 lots. Take that same 60-pip stop on a $200 account. Risk is $2, and $2 ÷ $600 = 0.0033 lots. The smallest size available is 0.01 lots, which on a 60-pip stop costs about $6: three times the intended risk, and 3% of that balance. The formula is telling you something real: for that stop distance, the account is too small to trade at 1%. The options are a closer stop if the chart supports one, an instrument with a smaller pip value, or no trade.

Why margin and leverage are not the same as risk

This confusion is expensive.

Margin is the deposit held while a position is open. Above, 0.06 lots of EUR/USD is 6,000 units of the base currency, roughly $6,480 of exposure at 1.0800. At 1:30 leverage the margin held is about $216; at 1:100, about $64.80.

Risk is what the trade can cost you: about $18.60.

Higher leverage lowers the margin held, letting you open a larger position with the same deposit. It does not change what a pip is worth. Use the extra room to trade 0.60 lots instead of 0.06 and being stopped out at the same level costs about $186 instead of about $18.60. Leverage and margin explained covers the mechanism.

Leverage decides how much you can open. Position sizing decides how much you should.

Where the stop-loss goes, and what it cannot do

A stop-loss turns the calculation into something real; without one, the number is a hope, not a limit.

Place it at the price that would show the reason for the trade no longer holds: beyond a level, beyond a recent swing, beyond the point where the idea was valid. Placing it at whatever distance produces the size you wanted is the earlier error in disguise.

One thing it does not do is fix your exit price. When triggered it becomes a market order, so if price gaps over a weekend or on a scheduled release, the position closes at the first available price, well past your level. The $18.60 above is the cost under normal conditions, not a ceiling. The stop and the size only work as a pair.

Total risk when you hold more than one position

Sizing each trade at 1% is half the job. Five open positions at 1% each is 5% of the account exposed at once.

It can be worse than it looks. Long EUR/USD, long GBP/USD and short USD/CHF are three tickets but largely one bet against the US dollar. If the dollar strengthens sharply they move against you together, and the careful per-trade sizing measured the wrong thing. Count related positions as one exposure.

Most people who use a per-trade limit also set a total one: a cap on how much of the account can be at risk at once. The figure is yours; having one is the point.

The account also carries its own conditions — the margin level at which positions begin closing automatically, and whatever account-level measures apply to your account type. Wisuno sets these out on its demo account page, worth reading before you need them. They describe what happens after your own limits have been passed, and they are not a substitute for sizing the trade.

Key takeaways

• The cost of being wrong is the stop distance in pips multiplied by the pip value at your size, and you set both before entering.
• Position size in lots equals risk in money divided by the stop distance in pips multiplied by the pip value per lot, rounded down.
• The stop-loss distance comes from the chart and the size is calculated to fit it, never the other way round.
• Margin is what is held while a position is open, risk is what it can cost you, and higher leverage changes only the first.

Common questions about forex risk management

What is the 1% rule in forex trading?

A limit on a single trade: the position is sized so that if the stop-loss is hit, no more than 1% of the account balance is lost. On a $5,000 balance that is $50. Because it is a percentage, the amount at stake falls automatically when the balance does.

How do I work out lot size from my stop-loss?

Divide your risk in money by the stop distance in pips multiplied by the pip value of one lot. For a $50 risk, a 25-pip stop and EUR/USD at $10 per pip per lot: 50 ÷ (25 × 10) = 0.20 lots, rounded down to the nearest step your account allows.

Does a wider stop-loss mean I am taking more risk?

Not by itself. A wider stop with a correspondingly smaller position costs the same if it is hit. What raises risk is widening the stop while keeping the size unchanged, or moving a stop further away once the trade is open.

How many positions should I have open at the same time?

There is no correct number, but they add up. Positions in related instruments often move together, so several trades can behave as one. Set a limit on total risk across everything open, count correlated positions as one exposure, and size to that total.