Key Margin Formulas
1. Borrowed Loan & Equity
\(\text{Investor Equity} = \text{Purchase Amount} \times \frac{\text{Initial Margin \%}}{100}\) \(\text{Margin Loan} = \text{Purchase Amount} - \text{Investor Equity}\)
2. Margin Call Price Drop Threshold
\(\text{Max Price Drop \%} = 1 - \frac{1 - (\text{Initial Margin \%} \div 100)}{1 - (\text{Maintenance Margin \%} \div 100)}\)
Margin Position Risk Table ($50,000 Purchase @ Reg T 50% / 9.5% Interest)
| Metric | 50% Initial Margin | 60% Initial Margin | 75% Initial Margin |
|---|---|---|---|
| Investor Cash Required | $25,000.00 | $30,000.00 | $37,500.00 |
| Borrowed Margin Loan | $25,000.00 | $20,000.00 | $12,500.00 |
| Annual Margin Interest (9.5%) | $2,375.00 / yr | $1,900.00 / yr | $1,187.50 / yr |
| Max Stock Price Drop Before Call | -33.3% Drop | -46.7% Drop | -66.7% Drop |
How to Use This Margin Calculator
- Select your preferred account currency from the header picker.
- Enter total stock purchase amount (e.g., $50,000).
- Input initial margin requirement (%) (standard Reg T 50%).
- Set annual margin interest rate (%) charged by your broker.
- Set maintenance margin requirement (%) (standard FINRA 25%).
- View investor equity, borrowed loan, annual interest, and margin call threshold.
Frequently Asked Questions
What is margin trading in stock markets?
Margin trading allows investors to borrow funds from a brokerage firm to purchase more stock shares than they could with cash alone, amplifying both potential gains and losses.
What triggers a margin call?
A margin call occurs when your account equity falls below the brokerage maintenance margin requirement (typically 25% to 30%), requiring you to deposit cash or liquidate positions.
How does Regulation T (Reg T) govern initial margin?
Federal Reserve Regulation T dictates that investors must deposit at least 50% of the total purchase price in cash or eligible securities when buying stocks on margin.
How is annual margin interest calculated?
Margin interest is calculated daily on your outstanding borrowed loan balance based on your brokerage’s annual margin interest rate, and billed monthly to your account.
What happens if you do not satisfy a margin call?
If you fail to deposit cash or securities promptly, your brokerage firm has the legal right to sell your stock holdings without prior notice to cover the deficit.
Can you lose more money than your initial investment when trading on margin?
Yes! Because margin uses debt leverage, a severe stock price decline can wipe out 100% of your cash equity and leave you owing additional money to your broker.
Is my personal financial data saved on any server?
No. All calculations run locally inside your web browser. History and saved presets are stored strictly in your browser’s local storage.