Most traders open a trade based on gut feeling — putting in a random amount without any calculation.
This is gambling.
Professional traders calculate their exact position size before every single trade. It takes 30 seconds and completely transforms your risk management.
Position Size = Risk Amount ÷ Stop Loss Distance
That is it. Three inputs. One calculation. Complete position size.
Risk Amount
Your account size × your risk percentage.
$10,000 account × 2% risk = $200 risk amount.
Stop Loss Distance
The difference between your entry price and your stop loss price.
Entry: $80,000. Stop: $77,000. Distance = $3,000.
Position Size
$200 ÷ $3,000 = 0.0667 Bitcoin
If stopped out — you lose 0.0667 BTC × $3,000 = $200. Exactly 2% of account. ✅
Example 1 — Bitcoin trade:
Account: $10,000
Risk: 1% = $100
Entry: $80,000
Stop loss: $78,500
Stop distance: $1,500
Position size: $100 ÷ $1,500 = 0.0667 BTC
Dollar value of position: 0.0667 × $80,000 = $5,336
Example 2 — Ethereum trade:
Account: $5,000
Risk: 2% = $100
Entry: $3,000
Stop loss: $2,800
Stop distance: $200
Position size: $100 ÷ $200 = 0.5 ETH
Dollar value of position: 0.5 × $3,000 = $1,500
Example 3 — Small altcoin:
Account: $10,000
Risk: 1% = $100
Entry: $0.50
Stop loss: $0.42
Stop distance: $0.08
Position size: $100 ÷ $0.08 = 1,250 coins
Dollar value: 1,250 × $0.50 = $625
The stop loss distance dramatically affects position size.
Same risk — different stops:
Account: $10,000. Risk: 1% = $100.
Tight stop — $500 distance:
Position size = $100 ÷ $500 = 0.2 BTC
Dollar position = $16,000
Wide stop — $5,000 distance:
Position size = $100 ÷ $5,000 = 0.02 BTC
Dollar position = $1,600
Key insight:
Tighter stop = larger position size.
Wider stop = smaller position size.
Risk in dollars remains the same — $100.
This is why stop placement is critical. Placing stops too tight forces small positions. Placing stops correctly allows appropriate position sizes.
With leverage — the calculation changes slightly.
10x leverage example:
Account: $10,000
Risk: 1% = $100
Entry: $80,000
Stop loss: $79,200
Stop distance: $800
Without leverage:
Position size = $100 ÷ $800 = 0.125 BTC = $10,000 position
With 10x leverage:
You only need $1,000 margin to control $10,000 position.
But your loss is still $100 if stopped out.
Warning:
Leverage amplifies both gains AND losses.
A small adverse move can trigger liquidation.
For beginners — avoid leverage entirely.
Maximum 2-3x for experienced traders.
Before every trade ask:
If you cannot answer all four — do not enter the trade.
Many free calculators exist online. But understanding the formula manually is essential — so you know what the calculator is doing and can verify results.
Bookmark this formula:
Position Size = (Account × Risk%) ÷ Stop Distance
In the next topic we will study leverage in detail — one of the most dangerous and most misunderstood tools in crypto trading.