Mortgage Calculator — Monthly Payment & Amortization Guide

Calculators · Free guide
Couple reviewing mortgage payment on tablet — 3D illustration

Estimate monthly mortgage payments including principal, interest, property taxes, homeowners insurance, and PMI. Enter home price, down payment, rate, and term — see payment breakdown and full amortization schedule. The TetraKits Mortgage Calculator runs entirely in your browser — free, private, and ready on mobile or desktop.

Overview

Pre-approval letters, listing comparisons, and rent-vs-buy decisions all start with monthly payment math — not just principal and interest. Model taxes, insurance, and PMI to see the full picture of homeownership cost.

How to use the mortgage calculator

  1. Enter home price and down payment — Type purchase price and down payment amount or percent. Loan amount = price minus down payment.
  2. Set rate, term, and extras — Enter annual interest rate, loan term (15 or 30 years), plus optional property tax, insurance, and PMI monthly amounts.
  3. Read monthly payment — See principal + interest and total monthly payment including escrow. Compare loan scenarios with the loan calculator.

Common use cases

  • Enter home price and down payment: Type purchase price and down payment amount or percent.
  • Set rate, term, and extras: Enter annual interest rate, loan term (15 or 30 years), plus optional property tax, insurance, and PMI monthly amounts.
  • Read monthly payment: See principal + interest and total monthly payment including escrow.
  • Bookmark for quick access: Save the tool for repeat tasks without installing an app.

Frequently asked questions

What is included in the monthly payment?

Principal and interest are always included. Property tax, homeowners insurance, and PMI are optional add-ons that reflect typical escrow payments.

What is PMI?

Private Mortgage Insurance is required when down payment is below 20%. It protects the lender and adds to your monthly cost until you reach 20% equity.

How is principal and interest calculated?

Standard amortization: M = P × [r(1+r)^n] / [(1+r)^n − 1] on the loan amount after down payment.

Does this include closing costs?

No. Closing costs are one-time fees at purchase — this calculator shows recurring monthly payments.

Is this mortgage calculator free?

Yes. Unlimited scenarios with no signup.