πŸ“ŠRiskSizer

Stock Position Size Calculator

Calculate how many shares to buy based on your risk budget and stop-loss β€” for any stock: AAPL, TSLA, NVDA, or any other.

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Results update automatically as you type

Position Direction: -
Quantity: 0
Position Value: $0.00
Stop Loss Price: $0.00
Distance to Stop: 0%
Potential Loss: $0.00

πŸ“œ History

βš™οΈ Advanced settings Show/hide calculator blocks, choose exchange β–Ό

πŸ“ Form Blocks

Field for token / ticker input
If disabled β€” automatic TP 3:1
Include commission in calculations
ATR button in the stop loss toggle

πŸ“Š Result Blocks

Warnings and risk messages

πŸ“‘ Exchange for Quotes

Quotes are fetched from the selected exchange first. If not found β€” tries others.

Position sizing for stock traders

Stock trading is different from crypto in volatility β€” but the math is identical. Whether you trade AAPL, TSLA, or small caps, the position size formula defines your intended maximum loss per trade. Actual loss may differ due to slippage, gaps, or partial fills.

How the stock position size calculator works

Enter: (1) account balance, (2) risk percentage (typically 0.5–1%), (3) stock entry price, (4) stop-loss price. The calculator outputs the number of shares. Formula: Shares = Risk ($) Γ· (Entry βˆ’ Stop-loss).

Apple (AAPL) position sizing example

Account: $10,000. Risk: 1% = $100. AAPL entry: $185. Stop-loss: $181 (support level, distance: $4). Result: $100 Γ· $4 = 25 shares. Total position value: 25 Γ— $185 = $4,625.

Tesla (TSLA) position sizing example

Account: $20,000. Risk: 1% = $200. TSLA entry: $245. Stop-loss: $229 (ATR-based, distance: $16). Result: $200 Γ· $16 = 12.5 β†’ round down to 12 shares. Total value: $2,940.

Rounding shares β€” always round down

Unlike crypto which allows fractional quantities, stocks are traded in whole shares. Always round the calculated quantity DOWN (not to nearest) to ensure you never exceed your planned risk. Most brokers support fractional shares β€” check if yours does.

Using margin (leverage) with stocks

If your broker provides margin, the position size calculation stays the same β€” the stop-loss still defines your intended risk. Margin means you lock up less cash but your P&L moves the same amount. Always size from your stop-loss, not from your margin availability. Note that margin calls can close positions before your stop-loss triggers.

Earnings events and position sizing

Standard stop-losses are unreliable around earnings announcements β€” stocks can gap 10–20% on the report. Two options: (1) close your position before earnings, or (2) use options to define maximum risk. Standard position sizing does not protect against gaps.

Frequently asked questions

How many shares should I buy? ↓
Shares = Risk ($) Γ· (Entry price βˆ’ Stop-loss price). On a $10,000 account risking 1% ($100), with entry $185 and stop $181 (distance $4): $100 Γ· $4 = 25 shares.
What risk percentage is correct for stocks? ↓
Most traders use 0.5–1% per trade. Active daytraders sometimes use up to 2%. Long-term swing traders often use 0.25–0.5%. The key is consistency β€” pick one number and stick to it.
How do I handle fractional shares? ↓
Always round down to the nearest whole share. Example: 12.5 shares β†’ buy 12. This keeps your actual risk at or below your planned maximum. If your broker supports fractional shares, you can use the decimal result directly.
Does position sizing work for penny stocks? ↓
Yes, the formula is the same. However, penny stocks often have wide bid-ask spreads and low liquidity β€” your actual fill price may differ from your entry price, making precise position sizing harder to execute.
How does a trailing stop affect position size? ↓
Position size is calculated at entry using your initial stop-loss. Once you set a trailing stop, your risk automatically decreases as the price moves in your favour β€” you do not need to recalculate the position size.

Use the calculator above for instant share quantity. For a full guide on position sizing theory, see our position sizing guide.

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