Trading calculator
Margin Interest Calculator
Estimate how much interest a margin loan may cost over your chosen holding period.
Estimate margin interest
Use your broker's current margin rate and day-count convention for a closer estimate.
Interest
$58.56
Estimated interest over the chosen holding period.
Ending loan
$5,000.00
Projected loan balance after monthly changes.
Total due
$5,058.56
Ending loan balance plus estimated interest.
Daily average
$1.30
Average estimated interest charged per day.
What to enter
Use figures from the broker pricing page, account statement or trading platform. Leave unknown fields at zero rather than guessing.
Margin loan amount
Amount borrowed from the broker.
Annual interest rate
Margin rate shown in the broker's balance tier schedule.
Holding period
Number of days the loan remains open.
Day count
Use 360 or 365 depending on the broker convention.
Additional monthly borrowing
Optional amount added every 30 days.
Monthly repayments
Optional amount repaid every 30 days.
Related research
Continue from the estimate into broker reviews, rankings and methodology pages.
Calculator FAQ
Short answers about inputs, assumptions and limits.
How is margin interest calculated?
Brokers usually multiply the daily borrowed balance by the annual rate divided by the day-count convention, then sum the daily charges.
Do margin rates vary by loan size?
Many brokers use tiered rates, so balances can fall into different rate bands. Check the broker's current schedule.
Is margin interest charged if the position loses value?
Yes. Interest accrues on the borrowed amount regardless of how the investment performs.
Does this account for margin calls?
No. It only estimates borrowing cost. Margin calls depend on account equity, maintenance requirements and broker policy.