Margin call calculator
The price at which your broker calls you, how far away it is, and what it costs to make the call go away. Stocks on Reg T margin, or futures on maintenance margin. Six emails from the risk desk in two months taught me this is the arithmetic to run first.
The regulatory minimums are quoted from the rules and linked below. Your broker’s house requirements can be higher, and the number that matters is theirs, so read it off your account and type it in. The numbers already in the boxes are example inputs, not current margins. Replace them with yours.
The position
Where you are
The bar is the share price from the call price on the left to your purchase price on the right. The red mark is where you are now. When the green fill reaches the left edge, the email arrives.
The position
Where you are
The bar is your whole balance. The fill is the cushion above maintenance, which is the only part the market is allowed to take before the email arrives. Every point against you shrinks it by the point value times contracts. Futures have no initial-versus-maintenance loan; the cushion is all there is.
How the call price is calculated
Stocks. You put up the initial margin and the broker lends the rest: loan = shares × buy price × (1 − initial %). The loan does not shrink when the stock falls; your equity does. A maintenance call arrives when equity ÷ market value drops below the maintenance requirement, and solving for the price gives call price = loan ÷ (shares × (1 − maintenance %)). At 50% initial and 25% maintenance that is two thirds of your purchase price, which is why a 33% drop on full margin is the textbook call.
Meeting a stock call takes either cash equal to the shortfall, maintenance % × market value − equity, or selling enough shares that the remaining position is covered: shares to sell = shortfall ÷ (maintenance % × price). Selling is the cheaper number and the more painful one.
Futures. There is no loan. The exchange sets a maintenance margin per contract, your broker may set a higher one, and your account balance has to stay above contracts × maintenance. Every point the market moves against you takes point value × contracts out of the balance, so points to the call = (balance − contracts × maintenance) ÷ (point value × contracts), measured from wherever the market was when you read the balance, because the balance is already marked to that price. Meeting the call means depositing the shortfall or closing contracts, and mine did not wait: it sold at 9:45 AM Eastern, which is 8:45 by the Chicago clock the email’s 9am CST deadline was written in.
The rules quoted. Regulation T, 12 CFR 220.12(a): the margin required for a margin equity security is “50 percent of the current market value of the security or the percentage set by the regulatory authority where the trade occurs, whichever is greater.” FINRA Rule 4210(c)(1): maintenance margin on a long position is “25 percent of the current market value of all margin securities, as defined in Section 220.2 of Regulation T, except for security futures contracts, ‘long’ in the account.” Both read 2026-09-01 from law.cornell.edu and finra.org. Futures margins are set per contract by the exchange and the broker and are not quoted here because they change; point values for the contracts in the menu are from CME’s own contract specs, the same sources the futures calculator cites per contract.
What the email looks like
- My broker closed my trade for me. Again. Three margin emails in August 2026, the liquidation at 9:45 AM, and the arithmetic I did not run.
- Testing the FOMC pattern The July call: three emails on three days, one /MNQ contract, and the broker placing the exit at 9:59 AM.
- Blowing up my account The July 2024 week that started all of this.
- All the free tools Options, futures, dividend, stock average and net worth calculators, none of them gated.
Nothing here is investment advice, a recommendation, or a solicitation. Margin and futures can lose more than the amount deposited.