A mortgage down payment calculator converts an upfront contribution between dollars and a percentage of the purchase price. Home buyers can estimate the loan amount, monthly principal and interest, and the lifetime-interest effect of five additional percentage points down.
Mortgage down payment calculator
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How to use this mortgage down payment calculator
- Enter the home price for the scenario you want to review.
- Choose whether the down payment entry represents a percentage or a dollar amount.
- Add an example annual interest rate and fixed repayment term.
- Review the converted down payment, estimated loan balance, monthly payment, and comparison at five percentage points more down.
How the down payment changes the mortgage
When you enter a percentage, the calculator multiplies the home price by that percentage to determine upfront cash. When you enter dollars, it divides the cash amount by the price to display the equivalent percentage. In both cases:
Loan amount = Home price − Down payment
The remaining loan enters the fixed-payment formula. The monthly rate is the annual rate divided by 12 and 100, while payment count is the term in years multiplied by 12. The mortgage down payment calculator compares lifetime interest at the entered contribution with interest at five percentage points more down, capped at the full purchase price.
Worked down-payment example
Consider an example $400,000 home with 20% paid upfront. The down payment is $80,000, leaving a $320,000 mortgage. At an example 6.5% annual rate for 30 years, the estimated monthly principal-and-interest payment is approximately $2,022.62. Taxes, insurance, HOA dues, closing costs, and other housing expenses are separate from that payment.
At 25% down, the modeled loan would be $300,000. The mortgage down payment calculator comparison uses the same rate and term for both cases, isolating the effect of borrowing less. It does not assume that a larger contribution automatically changes the lender’s rate or fees.
Assumptions and limits
- The payment estimate models a fully amortizing fixed-rate mortgage with monthly installments.
- Rates, programs, minimum contributions, and underwriting requirements vary; verify every input with a lender.
- A contribution below 20% produces a plain reminder that PMI may be required, but no premium is estimated.
- Closing costs, prepaid escrow, moving expenses, repairs, taxes, insurance, and HOA dues are excluded.
- The five-percentage-point comparison changes only the borrowed amount and keeps the entered rate and term constant.
Mortgage down payment calculator FAQ
Are closing costs included in the down payment?
No. A down payment reduces the purchase amount being financed, while closing costs cover separate transaction and loan expenses. Request itemized estimates from both providers.
Does putting 20% down always eliminate mortgage insurance?
Requirements depend on the loan program, occupancy, lender, and terms. The calculator provides only a general PMI reminder and does not determine eligibility.
Can I compare a dollar amount with a percentage?
Yes. Switch the input format and enter either value. The results show both dollars and percentage so you can compare scenarios on the same home price.
Plan the payment and cash reserve together
After choosing an upfront amount, use the mortgage payment calculator for taxes and insurance, the total-interest calculator for lifetime cost, or the amortization calculator for a monthly schedule. The savings guide can help frame liquidity needs. Fannie Mae describes purchase price, down payment, term, and insurance in its mortgage calculator guidance.
Last reviewed: October 5, 2026
Author: Harsh Kardam
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Disclaimer: This is an educational estimate, not a rate quote, approval, or financial, legal, or tax advice. Verify current rates, fees, and terms directly with your lender or provider.
