Is total interest the same as APR?

No. Total interest is a dollar amount from the selected schedule. APR is an annualized cost measure that can include certain finance charges.

Why compare fixed payment and equal principal?

The same loan amount, APR, and term can produce different cash flow and total interest depending on how principal is repaid.

Does this include fees?

No. It focuses on interest from the entered APR. Add lender fees separately when comparing offers.

Loan Interest Calculator

Estimate total loan interest, total payments, interest as a percentage of principal, and fixed-payment or equal-principal payment amounts.

Loan amount ($)

APR (%/year)

Term (months)

What this loan interest calculator estimates

English search intent is usually total interest or finance charge, not the Russian idea of loan overpayment. This calculator estimates how much interest is paid over the term from loan amount, APR, and payment structure.

Total interest paid over the loan term.
Total payments before fees and optional products.
Interest as a percentage of the original principal.
Fixed monthly payment or equal principal comparison.

Not an official disclosure

This is not an APR disclosure, loan estimate, or Truth-in-Lending statement. Fees, payment dates, variable rates, and lender rules can change the real finance charge.

Interest formulas

T o t a l in t er es t = T o t a l p a y m e n t s - P r in c i p a l

Total payments come from the selected payment model.

I n t er es t s ha r e = \frac{T o t a l in t er es t}{T o t a l p a y m e n t s} \cdot 100%

This shows what part of all payments goes to interest.

I n t er es t a s p er ce n t o f p r in c i p a l = \frac{T o t a l in t er es t}{P r in c i p a l} \cdot 100%

This is a simple cost ratio, not APR.

What is not included

Origination fees, points, title fees, dealer fees, or insurance.
Exact calendar dates, daily interest, and lender rounding.
Late fees, prepayment penalties, deferment, forbearance, or refinance costs.
Credit approval, borrower eligibility, or contract compliance.

Frequently Asked Questions

Sources and References

Calculations are based on the listed reference sources. Links open in a new tab.

Updated: June 2, 2026

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