Stock Margin Calculator

Multiply the position value by the initial margin requirement to get the cash required. A $20,000 stock position at 50% initial margin needs $10,000 of your cash; the other $10,000 is the broker loan. Working backward, divide available cash by the margin rate: $10,000 ÷ 0.50 = $20,000 of buying power.

Buying power for this single trade is cash divided by the initial margin requirement expressed as a decimal. At 50%, each $1 of cash supports $2 of stock, so leverage is 2:1. At 40%, each $1 supports $2.50. Your broker may restrict a security to a higher requirement, which reduces that buying power.

Yes. All three fields are editable. The last one you change becomes the driver: cash solves for buying power and shares, shares solve for position value and cash, and position value solves for shares and cash. Changing stock price or initial margin then preserves that chosen driver.

Initial margin is the equity required when opening a position. Maintenance margin is the minimum equity percentage required while holding it. Initial margin sizes the purchase; maintenance margin sets the call threshold. A broker can impose house requirements above regulatory minimums for either one.

It means every $1 of your equity controls $2 of stock. Half of the position is your cash and half is borrowed. A 10% move in the stock is therefore roughly a 20% move on your original cash before interest and other costs.

Yes. Share counts are not rounded automatically, so a cash-driven result can include fractional shares. Whether you can actually trade that fraction depends on the broker and security; use a whole-share count as the driver if fractional trading is unavailable.

This tool uses simple daily interest: loan balance × annual rate × days ÷ 365. A $10,000 debit at 10% for 30 days is $82.19. Brokers may use a different day-count convention, post interest monthly, change the rate during the holding period, or apply tiered rates, so reconcile the estimate with the broker's schedule.

It commonly accrues daily even if it is posted to the account monthly. The calculator therefore shows both the daily cost and the projected total. The exact posting cycle does not make the economic cost disappear, but it can affect when the debit balance used by a broker's margin engine increases.

A margin loan is generally an outstanding debit every calendar day, not only a position held during market hours. The calculator accepts calendar days. Check the broker's agreement for its exact accrual and settlement conventions.

Add the projected interest to the purchase cost and divide by shares. Equivalently, add interest per share to the entry price. With 400 shares bought at $50 and $82.19 of interest, break-even is about $50.21 before commissions, taxes, dividends, or other fees.

Recalculate with the new annual rate or split the holding period into separate calculations for each rate. This page deliberately uses one rate for the whole period; it does not imply that a variable broker rate will stay fixed.

That depends on how the borrowed funds were used, the type and amount of investment income, elections, and local tax rules. This calculator does not produce a tax figure. Keep the broker's interest statements and use current tax guidance or professional advice rather than treating the projected cost here as a deduction.

For one long position, divide the debit balance by shares times one minus the maintenance rate: debit ÷ [shares × (1 − maintenance)]. The projected version on this page adds the selected interest to the debit. With a $10,000 loan, 400 shares, and 25% maintenance, the before-interest estimate is $33.33.

No. FINRA's general minimum for many long margin securities is 25%, but brokers can impose higher house requirements, and individual volatile or concentrated positions may require much more. Enter the actual percentage shown by your broker for the security.

A real account can contain other positions, cash, unsettled trades, concentrated holdings, security-specific requirements, interest postings, and house rules that this single-position model cannot see. Brokers also reserve the right to raise requirements. Use this result as a stress estimate, not as an account statement.

Do not assume so. Investor.gov warns that a brokerage firm may sell securities to cover a shortfall without informing you in advance, and the firm chooses what to sell. A calculated threshold is not a grace period.

For the isolated position, the stress table's deficiency is the maintenance requirement times market value minus current equity when that number is positive. A broker's actual demand can differ because it is based on the entire account and its current house rules.

It can. If accrued interest increases the account debit, the stock does not need to fall as far before equity reaches the maintenance threshold. That is why this page shows a before-interest call price and a projected price after the selected holding cost.

Yes. Leverage magnifies losses, interest continues to accrue, and a sharp gap can carry the position below the planned call threshold before liquidation occurs. You may still owe the broker after your original equity is gone.

No. Their margin systems, payoff shapes, and maintenance rules differ materially. This calculator models one long stock or ETF position with a cash equity contribution and a fixed broker loan.

No. Portfolio margin uses risk-based scenario models across eligible positions and offsets. It cannot be reproduced honestly from one stock price and two percentages. Use the calculator supplied by the broker or clearing system that holds the account.

No. CalcStocks does not hold market data or connect to brokerage accounts. You enter every assumption, calculations run locally in the browser, and nothing is sent to a server. That makes the method inspectable but also means you must supply current broker terms.

No. The output describes one mathematical scenario, not whether the security, leverage, or holding period is suitable. Volatility, liquidity, gaps, rate changes, concentration, and your ability to add funds are outside the arithmetic. Margin can create losses greater than the cash invested.