Position Size Calculator

Position size (shares) = Dollar Risk ÷ Risk per Share, where Dollar Risk = Account Size × Risk Percentage and Risk per Share = Entry Price − Stop Loss Price (for longs).

Example: $25,000 account, 1% risk ($250 dollar risk), entry $50, stop $48.50 ($1.50 risk/share) → 250 ÷ 1.50 = 166 shares. This calculator handles all three account types — cash (1×), margin (2×), intraday (4×) — and automatically caps shares at your available buying power.

Leverage multiplies your buying power, not your risk budget. With a $10,000 margin account at 2× leverage, you can hold a $20,000 position — but your dollar risk per trade should still be 1–2% of your $10,000 account equity, not your $20,000 buying power.

Leverage increases potential losses proportionally, so position size must always be calculated against your account equity. Using buying power as the risk base is one of the most common ways traders blow up leveraged accounts.

The calculator caps your position at whichever limit is lower: risk budget or buying power. When buying power is the binding constraint, a yellow warning appears.

This typically happens with low-priced, volatile stocks where a 1–2% stop allows hundreds of shares that cost more than your available capital. Solutions: increase capital, use tighter stops, or accept a smaller position that fits within buying power while still meeting your minimum R:R requirement.

Many educational risk-management frameworks discuss risking a small percentage of account equity per trade, often using 1% as an example rather than a universal rule.

At 2% risk, a 10-trade losing streak draws an account down about 18%. At 1%, the same streak costs about 9.6%. Use the calculator to understand the arithmetic, then choose limits appropriate to your circumstances and risk tolerance.

Shares = (Account × Risk%) ÷ (Entry × Stop%), where Stop% is the percentage distance from entry to stop.

Example: $20,000 account, 1.5% risk ($300), $45 entry, 3% stop loss ($1.35 risk/share) → 300 ÷ 1.35 = 222 shares. This calculator accepts an actual stop price (e.g., $43.65) rather than a percentage — you place stops at technical levels, then the calculator back-solves the share count.

FINRA eliminated the $25,000 PDT minimum in June 2026. Intraday margin now operates on risk-based tiers — standard stocks typically qualify for 4× leverage (25% maintenance margin), with S&P 500 components eligible for up to 6.67×.

The math of position sizing is unchanged: always risk 1–2% of account equity per trade, not 1–2% of buying power. Using 4× leverage to take oversized positions without proportionally tighter stops multiplies losses by the same factor it multiplies gains.