Margin Call Calculator
Calculate at what price a margin call occurs, your current equity percentage, and how much additional funds you need. Everything runs privately in your browser.
How Margin Calls Work
When you buy stocks on margin, you borrow money from your broker to purchase more shares than your cash alone would allow. Your broker requires you to maintain a minimum equity percentage in your account, known as the maintenance margin. If the value of your securities drops enough that your equity falls below this threshold, the broker issues a margin call — a demand that you deposit additional funds or sell securities to restore the required equity level.
The margin call price is the stock price at which your equity percentage equals the maintenance margin requirement. Knowing this price in advance helps you manage risk and decide whether to set stop-loss orders or prepare additional funds. Most US brokers require a 25% maintenance margin, though some may require 30% or more for volatile stocks.
Formulas
Equity = (Current Value - Loan Amount)
Equity % = Equity / Current Value × 100
Margin Call Price = Loan / (Shares × (1 - Maintenance Margin %))
Additional Funds Needed = (Maintenance Margin × Current Value) - Equity
Understanding Margin Requirements
There are two key margin requirements. The initial margin is the minimum equity you must have when first opening a margin position — typically 50% under Regulation T in the United States. The maintenance margin is the minimum equity you must maintain after the position is open — typically 25% per FINRA rules, though individual brokers may set higher requirements.
If your equity drops below the maintenance margin, you face a margin call. You generally must respond within 2-5 business days by depositing cash, depositing additional marginable securities, or selling existing securities. If you do not meet the margin call, your broker may sell your securities without notice to bring the account back into compliance.
Margin Call Example
Suppose you buy 200 shares at $50 each ($10,000 total) with $5,000 of your own money and $5,000 borrowed. Your initial equity is 50%. If the stock drops to $35, your account value is $7,000 but you still owe $5,000, leaving equity of $2,000 or 28.6%. With a 25% maintenance margin, you are still safe. But if the stock drops to $33, equity is $1,600 or 24.2%, triggering a margin call. You would need to deposit additional funds to bring equity back to 25% or more.
Managing Margin Risk
- Know your margin call price: Calculate it before entering any margin trade so you are never caught off guard.
- Use stop-loss orders: Set automatic sell orders above your margin call price to limit losses.
- Maintain a cash buffer: Keep extra cash or marginable securities in your account to absorb price drops.
- Diversify positions: Don't concentrate margin exposure in a single stock — diversification reduces the risk of a margin call.
- Monitor regularly: Check your equity percentage daily when holding margin positions, especially in volatile markets.