Mortgage Calculator Form
This calculator uses a responsive input grid: three columns on large screens, two on smaller screens, and one on mobile.
Formula Used
Monthly principal and interest payment:
M = P × [r(1+r)n] / [(1+r)n − 1]
Where:
- M = monthly principal and interest payment
- P = loan amount after down payment
- r = monthly interest rate (annual rate ÷ 12)
- n = total number of monthly payments
Total monthly housing cost: principal and interest + monthly property tax + monthly insurance + HOA + PMI + any extra payment.
Amortization logic: each month, interest is calculated from the current balance. The rest of the lender payment reduces principal. Extra payments reduce principal faster, which lowers future interest and shortens payoff time.
How to Use This Calculator
- Enter the home price and choose whether down payment is a percent or fixed amount.
- Add the annual interest rate and total loan term in years.
- Enter optional costs such as property tax, insurance, HOA, and PMI.
- Add an extra monthly payment to test faster payoff scenarios.
- Select the start month, then click Calculate Mortgage.
- Review the result summary, chart, and amortization schedule.
- Use the CSV or PDF buttons to export the schedule.
Example Data Table
Example only. Values below show one possible mortgage setup and output.
| Home Price | Down Payment | Interest Rate | Term | Annual Tax | Annual Insurance | Monthly HOA | Monthly P&I | Estimated Total Monthly Cost |
|---|---|---|---|---|---|---|---|---|
| $350,000.00 | 20% | 6.50% | 30 years | $3,600.00 | $1,200.00 | $75.00 | $1,769.79 | $2,244.79 |
FAQs
1) What does this mortgage calculator include?
It includes principal, interest, property tax, home insurance, HOA fees, PMI, and optional extra monthly payments. It also shows an amortization schedule, payoff date, total interest, and export options.
2) Why is my total monthly cost higher than principal and interest?
Principal and interest cover the loan itself. Total monthly cost can also include property taxes, insurance, HOA dues, PMI, and extra payments. Those added costs often make the real monthly housing payment much higher.
3) How does extra payment help?
Extra payment reduces principal faster. That lowers future interest charges because interest is calculated on the remaining balance. Even a small recurring extra payment can shorten the loan term and save a meaningful amount of interest.
4) What is PMI?
PMI stands for private mortgage insurance. Lenders often require it when the down payment is small. It protects the lender, not the borrower, and usually adds a monthly cost until equity reaches the lender’s required level.
5) Can I use a zero interest rate?
Yes. The calculator handles a zero-rate loan by dividing the loan amount evenly across all months. That gives a flat principal payment schedule without any interest charges.
6) What is amortization?
Amortization is the repayment pattern across the loan term. Early payments usually contain more interest and less principal. Later payments shift toward more principal as the remaining balance gets smaller.
7) Does the calculator estimate escrow?
It estimates escrow-style monthly costs by spreading annual property tax and annual insurance into monthly amounts. Actual lender escrow bills can differ because lenders may adjust for shortages, surpluses, or reserve requirements.
8) Should I enter down payment as percent or amount?
Use percent when comparing common loan scenarios, such as 10% or 20% down. Use amount when you already know the cash you plan to pay upfront. The calculator supports both methods.