Mortgage calculator: monthly payment and how much you can borrow
Enter the home price, down payment, interest rate and term: your monthly payment, the total cost of the loan and the amortization schedule appear instantly. Or find out how much you can borrow on your income.
- Monthly payment and APR
- How much can I afford?
- Amortization schedule
- CSV export and printing
100% private — Everything is processed directly in your browser: your files, voice, and image are never sent to Chatzam's servers.
How to use the mortgage calculator
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Describe the purchase
Enter the home price, your estimated closing costs and your down payment: the loan amount (price + closing costs − down payment) is calculated for you. Set closing costs to 0% if you pay them in cash or if the price you entered already includes them. An example is pre-filled: change it to match your plans.
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Set the rate, term and insurance
Enter the interest rate from your quote or a lender's offer, the loan term in years and any mortgage insurance, either as a percentage of the loan per year or as a fixed amount per month. Lender fees are optional.
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Read the results and keep them
Your monthly payment, total interest, insurance cost, APR and total repaid appear. Download the amortization schedule as a CSV file or print it to PDF. The How much can I borrow tab estimates the home price you can afford.
Everything you need before buying a home
Monthly payment and the real cost of the loan
Payment with and without insurance, total interest, insurance cost, any fees and total repaid, updated as you type.
Affordability based on your debt-to-income ratio
From your gross monthly income, your other debt payments and a maximum debt-to-income ratio you choose (for example 36%, the classic rule of thumb), the tool estimates how much you can borrow and the home price you can afford once closing costs are set aside.
Amortization schedule
Year by year, with a month-by-month breakdown in one click: interest, principal paid and remaining balance. Export to CSV for your spreadsheet or print to PDF.
Principal and interest chart
A yearly chart shows the principal share growing and the interest share shrinking, which helps you see the benefit of a shorter term or of extra payments.
How is a monthly mortgage payment calculated?
On a fixed-rate mortgage, the payment stays the same every month: it depends on the amount borrowed, the interest rate and the number of payments. For example, $300,000 borrowed at a hypothetical 6% over 30 years costs about $1,799 a month in principal and interest. This mortgage payment calculator uses the standard amortization formula lenders use, payment = loan × monthly rate ÷ (1 − (1 + monthly rate)^−number of months), then adds mortgage insurance if you enter it. It also shows the total interest, so you can compare a 15-year and a 30-year mortgage: over 15 years the same loan costs about $2,532 a month, but total interest drops from about $347,500 to $155,700. Property taxes, homeowners insurance and HOA fees are not included: add them to the result to get your full monthly housing cost.
Interest rate, APR and mortgage insurance: what makes up the cost?
The interest rate is used to calculate the interest you pay each month. The APR (annual percentage rate) goes further: it adds lender fees, points and mortgage insurance, which makes it the better figure for comparing two offers. The calculator gives an approximate APR based on what you enter; the official figure is the one on your lender's loan documents, which may include other charges. On a conventional loan, lenders usually require private mortgage insurance (PMI) when you put down less than 20%. You can enter it as a percentage of the loan per year or as a fixed monthly amount, as shown on your quote.
How much house can I afford on my salary?
Lenders look at your debt-to-income ratio: the share of your gross monthly income that goes to debt payments. A well-known rule of thumb, the 28/36 rule, suggests spending no more than 28% of gross income on housing and 36% on all debts combined, but each lender and loan program sets its own limits. For example, with $6,000 gross a month and no other debts, 36% allows a payment of $2,160, which is about $360,000 over 30 years at a hypothetical 6% before insurance. The How much can I borrow tab starts from the ratio you choose, estimates the loan amount, then the home price after setting aside your closing costs. Your credit score and the lender's own rules can change the answer.
Down payment, closing costs and rates: plan the whole budget
A mortgage does not cover everything: closing costs often add around 2 to 5% of the price, plus moving costs and any repairs. A bigger down payment lowers your monthly payment, and reaching 20% usually lets you avoid PMI on a conventional loan. The rates pre-filled here are only editable examples, not today's mortgage rates: rates change constantly and depend on the lender, the term, your credit and your down payment. Compare several lenders and ask each one for its full costs before you choose.
Frequently Asked Questions
How much do I need to earn for a $300,000 mortgage?
At a hypothetical 6% over 30 years, the payment is about $1,799 a month before insurance and taxes. Under the 36% rule with no other debts, that means a gross income of about $5,000 a month; keeping housing to 28% means about $6,400. These are rough figures: enter your own rate and debts in the How much can I borrow tab.
What debt-to-income ratio do lenders accept?
There is no single limit. The 28/36 rule is a common guideline, and many lenders and loan programs accept more depending on your credit and savings. The ratio can be changed in the calculator.
What is the longest mortgage term?
30 years is the most common term, and 15 years is a popular shorter option. Longer terms are rare and cost much more in interest; the calculator shows a warning beyond 30 years.
Is the APR shown the same as on my loan offer?
No, it is an approximation. It includes the rate, the insurance and the fees you entered. The APR on your lender's official documents may include other charges and is the only binding figure.
Are the rates shown today's mortgage rates?
No. The pre-filled values are examples you should replace with the rate from your own quote. The tool does not know current market rates.
Is my data sent anywhere?
No. All calculations run in your browser; nothing is sent or stored. The result is an estimate, not a loan offer.