Margin Calculator
Estimate how much cash you need and how much you borrow when buying stock on margin at a given initial margin requirement.
FAQ for this calculator
- What is maintenance margin?
- Brokers require minimum equity if the stock falls—often 25%—not calculated here.
- Margin interest?
- Not included—borrowed amount accrues broker interest daily.
- Short selling?
- This calculator covers long margin purchases only.
- Pattern day trader rules?
- PDT equity minimums are separate from this simple cash/borrow split.
How to use the margin buying power calculator
Multiply share price by count for total position value, then apply the initial margin percentage for required equity.
- Enter current stock price per share.
- Enter number of shares to buy.
- Set initial margin (default 50% under typical Reg T).
When to use this calculator
- Sizing a leveraged stock purchase before placing an order.
- Comparing 50% vs 75% initial margin requirements.
- Understanding how much you borrow at a given equity level.
Examples & walkthrough
- $150 × 100 shares = $15,000 position; 50% margin → $7,500 cash, $7,500 borrowed.
- Higher margin % means more cash upfront and less borrowing.