Topic review
James Whitfield
Retired Financial Planner. Assigned as the finance topic reviewer for mortgage, retirement, annuity, pension, and long-term planning calculators.
Formula provenance
The methodology summary explains the formula family in use, and the source list points to the primary or authoritative references checked for this topic.
Methodology
Converts the entered annual margin rate into a daily accrual using the selected 360-day or 365-day basis, applies that daily rate to the net interest-bearing balance after any cash offset, and then derives daily, 30-day, annualized, and custom holding-period interest plus the implied break-even gain on the gross loan balance.
Limitations
- Assumes one constant quoted margin rate and one flat debit balance for the full holding period.
- Does not include rate tiers, compounding of unpaid interest, intra-period trading changes, or broker-specific balance-calculation rules beyond the simple cash offset shown here.
- The cash-offset treatment is an educational netting assumption and not a substitute for your broker’s own adjusted-debit calculation.
- This is an educational financing-cost tool only and not brokerage, legal, or investment advice.
Disclaimer
Use this calculator to estimate margin carry cost only. Your broker’s actual interest charge can differ based on account agreement, tiered rates, balance changes, and firm-specific debit-balance rules.
Change notes
Finance change note: the formula, tax or rate assumptions, source set, disclaimer, and planning guidance for this calculator were last reviewed on 2026-03-22. Report a correction at contact@calcipedia.org; substantive rule or assumption changes refresh both the reviewed date and the updated date shown on the page.
