Question 1

What is a position size calculator?

Accepted Answer

A position size calculator tells you exactly how many shares, contracts or lots to buy so that a hit to your stop loss costs no more than a pre-defined percentage of your account. It is the single most important tool in a professional risk-management workflow.

Question 2

How is position size calculated?

Accepted Answer

Position size = (Account balance × Risk %) ÷ (Entry price − Stop loss price). Bizzlytics computes this instantly as you type: enter your balance, the % of account you are willing to lose, and your entry + stop, and you get the exact share count.

Question 3

Why does position sizing matter?

Accepted Answer

Because the market decides your win rate — but you decide your position size. Consistent 1–2% risk per trade keeps drawdowns survivable; oversized positions cause blow-ups even when the strategy has an edge.

Question 4

Example calculation

Accepted Answer

Account $10,000. Risk 1% ($100). Entry $100, stop $98. Per-share risk = $2. Shares = $100 / $2 = 50 shares. Total position value = $5,000 (which is fine because the actual money at risk is only $100).

Question 5

Common mistakes to avoid

Accepted Answer

1) Sizing by dollar amount instead of stop distance. 2) Ignoring commissions/slippage on tight stops. 3) Rounding shares up instead of down. 4) Widening the stop after entering — always accept a smaller size instead.

Question 6

Related tools

Accepted Answer

Pair this with the Risk/Reward Calculator to check if the trade is worth taking, and the Lot Size Calculator (forex) or Profit/Loss Calculator to preview outcomes.

Position Size Calculator

The formula

Frequently asked questions

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