Position Sizing: How Much to Risk Per Trade
Position sizing is the most important skill in trading and the one beginners skip entirely. It answers one question before every trade: if I'm wrong, how much do I lose? Get this right and no single trade can hurt you badly; get it wrong and one bad move ends the account. This guide walks through a simple, repeatable method. It's educational, not financial advice.
Risk per trade comes first, not leverage
Most beginners start with the wrong question: "how much leverage should I use?" The right first question is: "how much of my account am I willing to lose if this trade fails?" That number — your risk per trade — is the foundation everything else is built on.
A widely used guideline is to risk a small, fixed percentage of your account per trade, often in the 1-2% range. On a $1,000 account, 1% risk means a losing trade costs about $10. This is an illustrative example, not a rule you must follow — but the principle holds: pick a fixed fraction and keep it consistent. The point is survival. If you risk 1% per trade, you can be wrong many times in a row and still have most of your account intact to keep trading.
The three inputs you need
Fixed-risk sizing needs exactly three numbers:
- Account risk — the dollar amount you'll lose if stopped out (e.g. 1% of your balance).
- Entry price — where you get in.
- Stop-loss price — where you admit you're wrong and exit.
The distance between entry and stop, expressed as a percentage, is your stop distance. Everything about the trade's size flows from these three numbers. Notice what's missing: leverage. Leverage is an output of this process, not an input you choose up front.
The formula
Position size is simply your risk amount divided by your stop distance:
Position size (notional) = Account risk ÷ Stop distance %
Say you'll risk $10 and your stop is 2% away from entry. Then your position notional is $10 ÷ 0.02 = $500. That's the size where a 2% adverse move loses exactly $10. If instead your stop is only 1% away, the same $10 risk supports a $1,000 position — a tighter stop allows a larger position for the same risk.
The margin you post and the leverage that implies both fall out of this. A $500 position backed by $100 of margin is 5x; backed by $50 it's 10x. You didn't pick the leverage — the risk and stop distance dictated it. RektCalc's position size calculator does this arithmetic for you so you can set risk and stop, and read off the size directly.
Why the same risk can mean different leverage
This is the insight that reframes leverage entirely. A trade with a wide stop needs a smaller position (lower leverage) to keep risk fixed. A trade with a tight stop can carry a larger position (higher leverage) at the exact same dollar risk. High leverage is not inherently reckless — using high leverage with a stop that's far away is, because it means the position is oversized for its risk.
This is why traders who size properly can use double-digit leverage safely on tight setups, while a beginner using 3x with no stop and an oversized position is taking far more real risk. Leverage is a lever on capital efficiency, not a measure of how dangerous a trade is. Position size relative to your stop is what actually determines danger.
Worked example: same risk, four different stop distances
Take a $5,000 account risking a fixed 1% ($50) per trade, with $500 of margin posted each time. Only the stop distance changes:
| Stop distance | Position size ($50 ÷ stop%) | Implied leverage ($500 margin) |
|---|---|---|
| 0.5% | $10,000 | 20x |
| 1% | $5,000 | 10x |
| 2% | $2,500 | 5x |
| 5% | $1,000 | 2x |
Every row loses exactly $50 if stopped out. The only thing that changes is how much size — and how much leverage — that $50 of risk can carry. A trader who fixes leverage instead (say, always 10x) would have taken a $10,000 position on the 0.5% stop, risking $500 instead of $50: ten times the intended risk, for a stop that was simply tighter.
Common sizing mistakes
- Sizing by margin instead of risk. "I'll put $100 in" tells you nothing about what you lose if stopped out. Size by the loss, not the deposit.
- Moving the stop to fit a bigger position. The stop belongs where the trade idea is invalidated. Don't shrink it just to justify more size.
- Increasing risk after losses to "win it back." This is how a drawdown becomes a blow-up. Keep the percentage constant.
- Ignoring fees and funding. On tight-stop, high-turnover trades, costs can rival your intended risk. Account for them.
- Correlated positions. Five longs on five coins that all move together isn't five 1% trades — it's closer to one 5% trade.
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Frequently asked questions
How much should I risk per trade?
Many traders use a fixed 1-2% of account per trade as a guideline, but the exact number is personal. The key is that it's small and consistent, so a string of losses can't end your account. This is educational, not advice.
How do I choose leverage then?
You don't choose it directly. Set your risk amount and stop distance, calculate the position size, and the leverage is whatever that size divided by your margin works out to. Leverage is an output of sizing, not an input.
Should position size change with volatility?
Yes. Higher volatility usually means a wider stop to avoid noise, which means a smaller position for the same fixed risk. Sizing off your stop distance handles this automatically.
How many losing trades can 1% risk survive?
If you risk a fixed 1% of your current balance per trade and lose every single time, it takes about 69 consecutive losses to cut the account in half (0.9969 ≈ 0.50). At 2% risk that drops to roughly 34 losses; at 5% risk, about 14. Because the risk is a percentage of a shrinking balance rather than a fixed dollar amount, no finite losing streak can wipe the account to zero — but the cushion shrinks fast as the percentage grows, which is why 1-2% is treated as a ceiling, not a target.
Educational only — not financial advice.