How to calculate position size in crypto from your stop loss
Choose the money you can lose first; the stop distance then decides the lot size. Here is the formula, with examples for gold, forex and Bitcoin.
Most beginners choose a lot size and hope. Professionals do it the other way round: decide the money at risk, then let the stop distance set the size.
Size = Money at risk ÷ (Stop distance × Value of 1 point per unit)
Worked examples
| Market | Contract | Risk | Stop distance | Size |
|---|---|---|---|---|
| Gold XAUUSD | 1 lot = 100 oz, so $1 move = $100 per lot | $100 | $5.00 | 100 ÷ (5 × 100) = 0.20 lot |
| EURUSD | 1 lot = 100,000 €, 1 pip = $10 per lot | $50 | 25 pips | 50 ÷ (25 × 10) = 0.20 lot |
| Bitcoin | 1 unit = 1 BTC, $1 move = $1 | $50 | $800 | 50 ÷ 800 = 0.0625 BTC |
Notice the same $100 risk buys a bigger position when the stop is tight and a smaller one when it is wide. That is the point: every trade costs the same if it fails.
Include the brokerage
Spread and commission are paid whether you win or lose. To make a full stop cost exactly your risk, add the round-trip cost to the stop distance: for gold with about $0.40 per ounce of costs, a $5 stop sizes as if it were $5.40, giving 0.185 lot. The Ten12 position size calculator sizes this way.
Exchange contracts differ (for example USDT-settled perpetuals on crypto exchanges), so always check the contract size in the exchange's specifications before you trade.
The position size calculator does this arithmetic for you.
Quick check
You risk $100 on gold with a $10 stop (ignore costs). What size?
Answer: 0.10 lot. 100 ÷ (10 × 100) = 0.10 lot.
If the stop gets wider and the risk stays the same, the position size…
Answer: gets smaller. A wider stop needs a smaller size for the same money at risk.
Frequently asked questions
What is the formula for position size?
Position size = money at risk ÷ (stop distance × value of a one-point move per unit). For gold CFDs, a $1 move is worth $100 per standard lot of 100 ounces.
How do I include spread and commission?
Add the round-trip cost per unit to the stop distance before dividing, so that a full stop loss costs exactly the amount you planned to risk.
Educational content only, not investment, legal or tax advice. Trading carries a substantial risk of loss. See our risk disclosure.
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