Margin Call Calculator
Find the price at which a margin-bought stock position triggers a margin call, from purchase price, initial margin, and maintenance margin. Educational, not investment advice. Runs in your browser.
Equity you put down (Reg T minimum is 50%).
Broker minimum, often 25–30%.
For a long position, the margin call price = purchase price × (1 − initial margin) ÷ (1 − maintenance margin). Below it, your equity falls under the maintenance requirement and the broker issues a margin call — demanding you add funds or sell. Buying on margin amplifies both gains and losses and adds interest cost on the loan. This is educational, not investment advice. Everything runs in your browser.
About this tool
Buying stock on margin means borrowing money from your broker to purchase more shares than your own cash alone would allow, using the securities as collateral. It magnifies returns when the position rises — but equally magnifies losses when it falls, and that is where the margin call comes in. When you open the position you must put up an initial margin (the equity portion you fund yourself; US Regulation T sets this at 50% for most stocks). As the price moves, your equity is the position's market value minus the loan. Brokers require that equity stay above a maintenance margin — often 25% to 30%, sometimes higher for volatile names. If the price falls far enough that your equity drops below the maintenance requirement, the broker issues a margin call, demanding you deposit more cash or securities, or sell holdings to restore the ratio; if you don't act, the broker can liquidate your positions, potentially at the worst possible time. This calculator solves for that trigger price using the standard relationship for a long position: margin call price = purchase price × (1 − initial margin) ÷ (1 − maintenance margin). It also shows the percentage decline from your entry that would trigger the call, along with the position value, the size of the margin loan, and your starting equity, so you can see how much cushion you have. The key takeaway the numbers make concrete is that lower initial margin (more leverage) and a higher maintenance requirement both move the call price closer to your entry, leaving less room for the stock to fall. Margin loans also accrue interest, a cost not modeled here. This is educational and explicitly not investment advice. Everything runs in your browser; nothing is uploaded.
How to use it
- Enter the purchase price per share and the number of shares.
- Enter the initial margin percentage you funded (Reg T minimum is 50%).
- Enter the broker's maintenance margin requirement (often 25–30%).
- Read the margin call price, the percentage decline that triggers it, and your loan and equity.
Frequently asked questions
- How is the margin call price calculated?
- For a long position: margin call price = purchase price × (1 − initial margin) ÷ (1 − maintenance margin). For a $100 purchase at 50% initial and 25% maintenance margin, the call price is $100 × 0.5 ÷ 0.75 = $66.67.
- What is the difference between initial and maintenance margin?
- Initial margin is the equity you must put up to open the position (Reg T: 50% for most US stocks). Maintenance margin is the minimum equity percentage you must keep afterward (often 25–30%). Falling below maintenance triggers a margin call.
- What happens during a margin call?
- The broker demands you restore your equity by depositing cash or securities, or by selling holdings. If you do not meet the call, the broker can liquidate your positions — sometimes without further notice and at unfavorable prices.
- How does leverage affect the margin call price?
- More leverage (a lower initial margin) moves the call price closer to your entry, so a smaller drop triggers it. A higher maintenance requirement does the same. Both reduce the cushion before a call.
- Does this include margin interest?
- No. Margin loans accrue interest, which erodes returns and is a real cost of trading on margin. This tool computes the call price from margin requirements only; factor in interest separately.
- Is this investment advice?
- No. It is an educational calculator. Trading on margin carries amplified risk, including losing more than your initial investment. Nothing is uploaded; all math runs in your browser.