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Margin Interest Calculator
Enter your margin loan balance, broker interest rate, and holding period to instantly see your daily interest charge, monthly cost, and total borrowing expense — works worldwide.

Enter Loan Details

Amount borrowed from your broker
Check your broker's margin rate schedule
How long you plan to hold the position
Used to calculate margin utilization %
Typical: 25% FINRA min, 30–40% at most brokers
Estimates your after-tax interest cost

Your Interest Breakdown

Enter your margin balance and rate on the left, then click Calculate to see your full interest breakdown.

Total Interest Charged
$0.00
for 30 days
Cost Breakdown
Margin Balance —
Annual Rate —
Daily Interest —
Monthly Interest (30 days) —
Annual Interest Cost —
Formula Used:
Daily Interest = Balance × Rate ÷ Day Basis
Total Interest = Daily Interest × Days Held
Quick Examples
Quick Settings
Margin Balance
$10,000
$1K$500K
Annual Interest Rate
8.00%
0.5%25%
Holding Period
30 days
1 day365 days
Marginal Tax Rate
0%
0%50%
Total Account Value
—
$0$1M
Maintenance Req.
25%
0%60%
Day Count Basis
Compounding
Currency
Behaviour
Auto-recalculate on slider change
Show charts after calculation

Interest vs. Principal

Cumulative Interest Over Time

How Margin Interest Works

When you buy securities using borrowed money from your broker, the amount you owe is called your debit balance. Your broker charges daily interest on this balance at the margin rate.

Most U.S. brokers use a 360-day year to compute daily interest. The formula is simple:

Daily Interest = (Debit Balance × Annual Rate) ÷ 360

Interest accrues every calendar day — including weekends and holidays. It is typically posted to your account once per month.

  • Interest is charged even if you are not actively trading
  • The rate often decreases as your balance grows (tiered pricing)
  • Dividends received do not offset margin interest automatically
  • Your debit balance can rise if you don't pay the accrued interest

Quick Reference: Common Margin Rates

Broker / TypeTypical Rate RangeNotes
Large US banks10–14%Full-service accounts
Discount brokers6–12%Varies by balance tier
Interactive Brokers~5–7%Competitive, tier-based
Robinhood Gold~6%Flat rate for Gold members
M1 Finance Plus~4–7%Lower for large balances
Portfolio margin accounts3–9%Requires high equity

Rates change frequently. Always confirm your exact rate in your broker's fee schedule or account settings.

Margin Call & Maintenance Basics

A margin call happens when your equity falls below the broker's maintenance requirement (usually 25–40% of total position value).

  • FINRA minimum: 25% maintenance margin
  • Most brokers: 30–40% house requirement
  • Reg T initial margin: 50% of purchase price
  • When a call is issued, you must deposit funds or liquidate positions within 2–5 business days (or sooner at broker's discretion)

Rising interest charges increase your debit balance over time, which can itself push you closer to a margin call if portfolio values stay flat.

Tips to Reduce Margin Borrowing Cost

  • Pay down the balance faster. Every dollar paid off reduces daily interest immediately.
  • Compare brokers. Rate differences of 2–5% per year can mean hundreds of dollars on a $20,000 balance.
  • Use margin only short-term. The longer you hold borrowed positions, the more interest compounds.
  • Check tiered pricing. Some brokers lower your rate if your balance exceeds a threshold (e.g., $100k).
  • Account for tax deductibility. If eligible, the after-tax cost is lower than the stated rate.
  • Monitor your utilization. High margin utilization increases margin call risk if markets drop.

Daily Interest Charge by Balance & Rate (360-day basis)

How much interest accrues per day at different margin balances and annual rates.

Annual Rate $5,000 $10,000 $25,000 $50,000 $100,000

Daily interest = Balance × Rate ÷ 360. These are simple interest values with no compounding.

Monthly Interest Cost (30 days) by Balance & Rate

Estimated monthly interest charge at different balances and broker rates (30 days × daily rate).

Balance 5% Rate 7% Rate 9% Rate 11% Rate 13% Rate

Monthly charge = Balance × Rate ÷ 360 × 30. Actual broker billing may vary slightly.

Annual Interest Projection by Balance & Rate

Total interest paid over a full year if you maintain a steady debit balance.

Balance 5% Rate 7% Rate 9% Rate 11% Rate 13% Rate

Annual cost = Balance × Rate. Simple interest — no compounding applied. Compounding increases actual costs if interest is not paid monthly.

Global Broker Margin Rate Reference

Approximate margin rates from major brokers and regions. Always verify current rates with your broker directly.

Broker / Region Small Balance Rate Large Balance Rate Day Count Billing Cycle Notes
Interactive Brokers (US)~6.8%~5.3%360MonthlyVery competitive; tiered
Charles Schwab (US)~13.3%~10.8%360MonthlyBase rate + spread
Fidelity (US)~13.3%~9.5%360MonthlyTiered by debit balance
TD Ameritrade (US)~13.3%~11.0%360MonthlyNow merged with Schwab
Webull (US)~6.99%~6.99%360MonthlyFlat rate
Robinhood Gold (US)~6.0%~6.0%360MonthlyFlat; Gold subscription req.
Trading 212 (EU/UK)~3–5%~3–5%365DailyCurrency-specific
eToro (EU)6.4%6.4%365NightlyCFD overnight charges
IBKR Canada~6.5%~5.3%365MonthlyCAD margin rate
CommSec (AU)~10%~9%365MonthlyAUD debit balance

Rates are approximate and subject to change. Contact your broker or check their website for the current rate schedule before trading on margin.

Effective After-Tax Margin Rate at Common Tax Brackets

If margin interest qualifies as investment interest expense, your real cost is lower than the stated rate.

Stated Rate 10% Tax 22% Tax 24% Tax 32% Tax 37% Tax

After-tax rate = Stated Rate × (1 – Tax Rate). Only applicable if margin interest is deductible in your jurisdiction. Consult a tax professional.