Refinance calculator
A refinance calculator helps you see how changing the interest rate, loan term, or balance affects your monthly payment and the total cost of the loan.
It’s useful when you’re considering switching to a lower rate or adjusting the repayment period. The tool does not account for fees, taxes, or insurance that may be added to a real refinance.
Calculators Wiki offers a quick way to run these numbers without any registration.
How it's calculated
Formula
The standard amortization formula for a fixed‑rate loan is used:
``` M = P * r * (1 + r)^n / ((1 + r)^n - 1) ``` where: - M = monthly payment - P = loan principal (balance after refinance) - r = monthly interest rate (annual rate ÷ 12 ÷ 100) - n = total number of payments (months)
Worked example
Suppose you refinance a $200,000 mortgage at 3.5% annual interest for 30 years. - r = 3.5 / 12 / 100 = 0.0029167 - n = 30 * 12 = 360 - M = 200,000 * 0.0029167 * (1 + 0.0029167)^360 / ((1 + 0.0029167)^360 - 1) - M ≈ $898.09 per month
Over the life of the loan you would pay about $123,312 in interest.
For a different scenario you can try the mortgage calculator on the same site.
For more details on how lenders calculate payments, see the Consumer Financial Protection Bureau’s guide: consumerfinance.gov