ROI Math

Real estate calculator

Mortgage Calculator

Estimate the monthly mortgage payment for a home or rental property. Enter price, down payment, interest rate, term, taxes, insurance, and HOA to calculate principal and interest, total monthly payment, loan amount, LTV, annual debt service, and total interest.

Last updated 2026-06-21

Mortgage Calculator
Estimate principal, interest, taxes, insurance, and HOA.
$3,244/mo
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yr
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$
Total monthly payment
P&I + tax + insurance + HOA
$3,244
Principal & interest
$2,594
Loan amount
$400,000
Annual debt service
$31,133
LTV
80.00%
Down payment: $100,000
Total interest: $533,981
Taxes / month: $500
Insurance / month: $150

Mortgage payment formula

The principal and interest payment uses the standard amortizing loan formula:

Payment = P × r × (1 + r)^n ÷ ((1 + r)^n - 1)

P is the loan amount, r is the monthly interest rate, and n is the total number of monthly payments. Taxes, insurance, and HOA are added after the loan payment to estimate the full monthly housing cost.

How investors use it

Mortgage payment is the bridge between purchase price and cash flow. Annual principal and interest becomes debt service for the DSCR calculator, while the down payment and debt service affect the cash-on-cash return calculator.

For underwriting, keep the loan payment separate from operating expenses. Property tax and insurance may be paid through escrow, but they are still property expenses when calculating NOI.

How to calculate a mortgage payment in 3 steps

  1. Subtract the down payment from the purchase price to get the loan amount.
  2. Use the interest rate and loan term to calculate monthly principal and interest.
  3. Add taxes, insurance, and HOA dues to estimate the total monthly payment.

Frequently asked questions

What does a mortgage calculator include?

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A mortgage calculator usually starts with principal and interest, then adds optional monthly costs such as property taxes, homeowners insurance, and HOA dues. This calculator shows both the loan payment and the full monthly housing payment so investors can see debt service separately from escrow-style costs.

How is monthly mortgage payment calculated?

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Monthly principal and interest is calculated with the standard amortization formula using the loan amount, annual interest rate, and loan term. The loan amount equals purchase price minus down payment. Taxes, insurance, and HOA are then added separately to estimate the total monthly payment.

What is PITI?

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PITI means principal, interest, taxes, and insurance. Principal and interest repay the loan; taxes and insurance are property-level costs that may be escrowed by the lender. HOA dues are often tracked separately, so this calculator shows them as a separate input.

Does annual debt service include taxes and insurance?

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In real estate underwriting, annual debt service usually means mortgage principal and interest only. Some lenders use a stricter PITIA payment that includes principal, interest, taxes, insurance, and association dues. Confirm the lender's definition before comparing DSCR or qualification thresholds.

How does down payment affect mortgage payment?

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A larger down payment reduces the loan amount, lowers loan-to-value (LTV), and usually lowers the monthly principal and interest payment. It also increases cash invested, so investors should compare the mortgage result with cash-on-cash return and DSCR.

This mortgage calculator is for educational estimates only and is not financial, lending, tax, or investment advice. Actual payments vary by lender fees, escrow rules, taxes, insurance premiums, mortgage insurance, and loan terms.