Estimate your monthly mortgage payment including principal, interest, taxes & insurance. Full amortization schedule with US, Canada, UK & Australia support.
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A mortgage calculator is a financial planning tool that applies the standard amortization formula — M = P × [r(1+r)ⁿ] ÷ [(1+r)ⁿ − 1] — to determine a homebuyer's fixed monthly payment based on loan principal, interest rate, and loan term. Beyond the base payment, it models the full amortization schedule (principal vs. interest split over time), compares 15-year vs. 30-year loan costs, and incorporates optional inputs such as property taxes, homeowner's insurance, PMI, and HOA fees to produce an all-in monthly housing cost estimate used by buyers, lenders, and real estate professionals.
How to Use This Mortgage Calculator
Enter your home price, down payment, interest rate, and loan term. Expand the optional fields to include property taxes, homeowner's insurance, PMI, and HOA fees for a more accurate picture. Hit Calculate to see your monthly payment, full amortization schedule, and a 15 vs. 30-year comparison.
The Mortgage Payment Formula
The standard amortization formula calculates your fixed monthly payment based on three inputs: the loan principal (P), monthly interest rate (r), and number of payments (n):
M = P × [r(1+r)ⁿ] / [(1+r)ⁿ − 1]
How Much Is a 3.5% Down Payment?
A 3.5% down payment is the minimum required for an FHA loan in the US. On a $150,000 home that's $5,250 down, leaving a loan balance of $144,750. On a $300,000 home it's $10,500; on a $400,000 home, $14,000. FHA loans allow lower credit scores than conventional loans but require mortgage insurance premiums (MIP) for the life of the loan in most cases. Use the down payment slider above to see exactly how your deposit size affects your monthly payment and total interest paid.
How Much Interest Do You Pay Over the Life of a Mortgage?
On a $300,000 loan at 6.75% over 30 years, total interest paid exceeds $395,000 — more than the original loan amount. This is why the amortization schedule matters: in year one, roughly 80% of each payment is pure interest. By year 15 the split is closer to 50/50. Choosing a 15-year term at the same rate cuts total interest to around $170,000 — a saving of over $225,000 — at the cost of a higher monthly payment. The amortization chart above makes this visible year by year.
Your Mortgage vs. Your Car Loan: The DTI Connection
Lenders don't assess your mortgage in isolation — they calculate your Debt-to-Income (DTI) ratio, which includes all monthly debt: mortgage, car loans, student loans, and credit cards. Most conventional lenders cap total DTI at 43–45%. A monthly payment on a $20,000 car loan (roughly $377 at 5% over 60 months) directly reduces how much mortgage you qualify for. As a rough rule, every $100/month in existing debt reduces your maximum mortgage by approximately $10,000–$15,000. Factor in existing payments before using this calculator to avoid overestimating your home budget.
🇨🇦 Canadian Compounding
Canada's Interest Act mandates semi-annual compounding for fixed-rate mortgages. The effective monthly rate is: (1 + rate/2)^(1/6) − 1. At the same nominal rate, this produces a slightly higher monthly payment than a US loan.
🇦🇺 Australian Fortnightly
Paying half your monthly payment every two weeks = 26 payments/year, equivalent to 13 monthly payments. This strategy can cut a 30-year loan by 4–6 years and save tens of thousands in interest.
💡 What is PMI?
Private Mortgage Insurance is required when your US down payment is below 20%. It protects the lender — not you — and costs 0.5%–1.5% of the loan annually. Removable once you reach 20% equity.
📊 Amortization Explained
Early payments are mostly interest. Over time more goes toward principal. The schedule below shows exactly how your balance shrinks — and how much interest you're actually paying each year.
15-Year vs. 30-Year Mortgage: Which is Better?
A 30-year mortgage has lower monthly payments, giving you more cash flow flexibility. A 15-year mortgage costs significantly less in total interest — often 50–60% less — but requires higher monthly payments. Many financial advisors recommend the 30-year with voluntary extra payments, giving flexibility without commitment. Use the term toggle above to compare both scenarios for your exact numbers.
Frequently Asked Questions
What is a 3.5% down payment on a $150,000 house?
A 3.5% down payment on a $150,000 home is $5,250, leaving a loan balance of $144,750. This is the minimum down payment for an FHA loan. At 6.75% over 30 years, your principal and interest payment on that balance is approximately $938/month — before taxes, insurance, and the FHA mortgage insurance premium (MIP). Enter $150,000 as the home price and $5,250 as the down payment above to see your full estimate.
How much interest do you pay over the life of a mortgage?
It depends on your loan size, rate, and term. On a $300,000 loan at 6.75% over 30 years, total interest paid is approximately $395,000 — more than the original loan. On a 15-year term at the same rate, total interest drops to around $170,000. The amortization schedule in this calculator shows your exact interest and principal split for every year of your loan.
What is an accelerated bi-weekly mortgage payment?
Accelerated bi-weekly payments mean you pay half your monthly mortgage amount every two weeks. Because there are 52 weeks in a year, this results in 26 half-payments — equivalent to 13 full monthly payments instead of 12. That one extra payment per year goes entirely toward principal, shortening a 30-year mortgage by 4–6 years and saving substantial interest. Select Australia as your region above to enable fortnightly payment mode.
How does Canadian mortgage interest compounding work?
Canada's Interest Act legally requires fixed-rate mortgages to compound semi-annually — twice per year — instead of monthly as in the US. To convert a Canadian annual rate to the correct monthly rate, the formula is: (1 + annual_rate / 2)^(1/6) − 1. A Canadian mortgage quoted at 6% produces a slightly higher monthly payment than a US mortgage at 6%. This calculator applies the correct formula automatically when you select Canada as your region.
What is the monthly payment on a $20,000 car loan — and how does it affect my mortgage?
A $20,000 car loan at 5% over 60 months has a monthly payment of approximately $377. Lenders include this in your Debt-to-Income (DTI) ratio when calculating mortgage eligibility. Most conventional lenders cap total DTI at 43–45% of gross monthly income. That $377 car payment can reduce your maximum mortgage qualification by $30,000–$40,000 depending on your income and other debts. Always factor in existing debt before estimating your home budget.
What is an amortization schedule and how do I read it?
An amortization schedule is a year-by-year table showing how each payment splits between principal and interest. In the early years of a 30-year mortgage, roughly 75–80% of each payment is interest. By the midpoint that ratio approaches 50/50, and in the final years the majority goes to principal. Your schedule shows exactly how much equity you're building each year. This calculator generates a full year-by-year amortization table after you hit Calculate.
Methodology & Data Sources: This calculator uses the standard amortization formula for US/UK/AU markets and applies semi-annual compounding as mandated by Canada's Interest Act for Canadian mortgages. Australian fortnightly and weekly calculations use the standard assumption of exactly 52 weeks per year. Property tax and insurance defaults are based on US national averages from the US Census Bureau and Insurance Information Institute. This tool is for estimation purposes only and does not constitute financial or mortgage advice. Always consult a licensed mortgage professional for binding rate quotes. Last updated: May 2026.