Position size calculator
Decide what you are willing to lose first, then let the stop distance determine the size. This is the opposite of picking a size and hoping the stop holds.
- Amount at risk
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- Stop distance
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- Margin required
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- Leverage needed
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- Profit at target
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- Risk / reward
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The formula
The stop distance is what converts a dollar risk into a position size. A tight stop allows a big position for the same risk; a wide stop demands a small one. That relationship is the whole point — it stops a volatile setup and a quiet one from being sized identically.
Why leverage is an output, not an input
Most people choose leverage first and discover their risk afterwards. Reverse it. Once the position size is fixed by your risk and your stop, leverage is simply whatever multiple gets you that exposure with the margin you are prepared to post. If that number is higher than your exchange allows, the trade is too big — widen the stop or accept less size, do not raise the risk.
Things this does not account for
- Slippage and gaps. A stop is a request, not a guarantee. In a fast move you can be filled well past it, and crypto gaps over weekends on some venues.
- Fees. Round-trip taker fees on a leveraged position are a real cost — check the exchange fee calculator.
- Correlation. Five 1% risks on five altcoins is not five separate bets. In a drawdown they move together, so treat it as one 5% risk.
- Liquidation. Size is one thing, survival is another — check the liquidation price sits well beyond your stop.