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Specialised calculators

Mortgage tools

The main calculator shows your monthly payment. These tools answer the questions that come before and after that number — what you can afford, whether refinancing pencils out, and what an extra payment actually buys you.

Calculators

How these tools fit into the mortgage process

Start with affordability

Before you browse listings or speak to a lender, you need a realistic price ceiling. The affordability calculator applies the 28/36 debt-to-income rule — the same framework most US lenders use — to your gross income, existing monthly debts and down payment. The result is a three-tier range: a conservative budget that keeps you well inside the limits, a comfortable middle ground, and a stretch ceiling that is technically approvable but leaves little room for unexpected costs.

Knowing your ceiling before you search means you never fall in love with a home that is outside your range, and you walk into a lender conversation with a clear number already in mind.

Then model the full payment

Once you have a target price, open the main mortgage calculator to see the complete monthly payment — principal, interest, property tax, home insurance, HOA fees and PMI if applicable. Each affordability tier links directly to the main calculator pre-filled with the right figures, so the transition takes one click.

The full calculator also shows the amortization schedule, the month your PMI drops off, and how extra payments shorten the loan — all the details that matter once you have a specific property in mind.

Evaluate refinancing and extra payments

Later in the loan lifecycle, two questions come up repeatedly: does refinancing at a lower rate actually save money after closing costs, and what does one extra payment per month really buy? The refinance break-even and extra payment impact tools — arriving shortly — answer both with concrete numbers rather than rough rules of thumb.

The break-even calculator compares your current rate against a new offer, factors in closing costs, and tells you exactly how many months it takes to recoup them. The extra payment tool shows the reduction in total interest and the number of months shaved off the loan term.

Why the 28/36 rule matters for your budget

The 28/36 guideline is the standard underwriting benchmark for conventional US mortgages. Understanding what it measures — and what it does not — helps you use it correctly.

28%

Front-end ratio

Your total monthly housing cost — principal, interest, property tax and homeowner's insurance (PITI) — should not exceed 28% of your gross monthly income. This is the limit lenders check first.

36%

Back-end ratio

Your housing cost plus all other recurring debt payments — car loans, student loans, credit card minimums — should not exceed 36% of gross income. This is often the binding constraint for buyers who carry existing debt.

3 tiers

Budget ranges

Rather than give a single ceiling, the affordability calculator shows three tiers: 80%, 90% and 100% of the maximum. Most financial planners recommend buying at the conservative or moderate tier to leave room for maintenance, emergencies and life changes.

Questions about these tools

How are these tools different from the main mortgage calculator?

The main calculator starts from a price you already have in mind and shows you the full monthly payment. These tools solve the upstream questions first — like how much you can afford before you start browsing, or whether the numbers on a refinance actually work. Each one is built around a single decision.

Do I need an account to use any of these tools?

No. Every tool on this site is free and requires no sign-up. Nothing is sent to a server — calculations run in your browser and any saved results stay in your local storage.

How accurate are the affordability estimates?

The affordability calculator applies the standard 28/36 debt-to-income guidelines used by most US lenders. It gives you a realistic range based on your income, existing debts and down payment — but every lender has its own criteria. Use the estimate to set your budget before talking to a lender, not as a substitute for pre-approval.

Can I link from a tool result to the main calculator?

Yes. Each tool result includes a link that opens the main mortgage calculator pre-filled with the figures from your scenario, so you can immediately see the full payment breakdown, amortization schedule and action plan.

Looking for the full payment breakdown? Open the US mortgage calculator or the Canadian one.