Simple Interest
Direct definition
Interest calculated only on principal, not on accumulated interest.
Written by the Vabasso Mortgage Editorial Team · Reviewed against agency and federal sources · Read our editorial policy for how we research and review mortgage content
Plain-English explanation
Most residential mortgages accrue on a monthly basis, effectively simple interest on the outstanding balance. Some private and daily-accrual loans compute interest per diem.
Why it matters
It's the base calculation behind your monthly interest charge.
Where you may see it
- Loan disclosures
- Amortization schedule
- Promissory note
A real-world example
On $400,000 at 6.5%, monthly interest = $400,000 × 6.5% ÷ 12 = about $2,167.
Educational and illustrative only
A common misunderstanding
Simple interest doesn't mean lower cost by default — how it's applied and compounded within a specific loan structure determines the actual cost.
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This glossary provides general educational information. Mortgage terminology, qualification methods, forms, timelines, fees, program rules, and legal meanings may vary by lender, investor, loan program, property, occupancy, state, and transaction. Definitions do not represent loan approval, legal advice, tax advice, or a commitment to lend.
- Author
- Vabasso Mortgage Editorial Team
- Reviewed by
- Vabasso Mortgage Licensed Advisory Team
- Last reviewed
- July 30, 2026