Buying a home is the biggest number most people ever sign for. The good news:
you can break that one scary number into a handful of smaller questions, and
each one has a calculator on this page. Work through them in order and you will
know what you can afford, whether a lender will say yes, what your loan really
costs over time, and whether buying even beats renting for your situation.
Every tool here runs in your browser. Nothing you type is sent anywhere, there
is no signup, and there is no “check your rate” button that hands your details
to a lender. These are educational estimates to help you plan — not financial
advice, not a loan offer, and not a rate quote. Real numbers depend on your
lender, your credit, your state, and the day you lock. Use these to get
oriented, then confirm the specifics with a lender you trust.
Before you shop: what you can afford
Two different questions hide inside “how much house can I afford?” One is about
your budget — what payment you can live with. The other is about the lender’s
rules — what they will actually approve. They are not the same, and smart
buyers check both.
Start with the price you can support
The Mortgage Affordability Calculator
works backward from your income. You enter what you earn, your other monthly
debt payments, your down payment, and a target debt-to-income limit, and it
solves for the largest home price those numbers can carry. It does not just
size the loan — it folds in property tax, homeowners insurance, HOA dues, and
PMI, because those are part of the real monthly bill.
It shows you three side-by-side scenarios so you can see how the rules change
your answer:
- Conservative — 28% of income to housing. The classic careful number.
- Standard — 36% back-end. The common conventional target.
- Aggressive — 43% back-end. The edge of what many programs allow.
Seeing all three at once is the point. The “aggressive” price is not a goal; it
is the ceiling. Where you land between conservative and aggressive is a personal
call about how much of your paycheck you want tied up in a house.
Then check whether you’d qualify
Affordability is your side of the math. Debt-to-income (DTI) is the lender’s
side. It is the share of your gross (pre-tax) monthly income that goes to debt,
and it is one of the first things an underwriter looks at.
The Debt-to-Income Ratio Calculator gives you two
numbers lenders care about:
- Front-end ratio — just your housing payment divided by gross income.
- Back-end ratio — housing plus all your other debt payments (car loans,
student loans, minimum credit-card payments) divided by gross income.
Here is the teaching most calculators skip: the limits depend on the loan
program. There is no single “good DTI.” The tool checks your ratios against
the common guidelines for four programs at once:
| Program | Front-end guideline | Back-end guideline |
|---|
| Conventional | about 28% | about 36% |
| FHA | about 31% | about 43% |
| VA | (no fixed front-end) | about 41% |
| Jumbo | (varies) | about 43% |
So a back-end DTI of 40% might be too high for a textbook conventional loan but
fine for an FHA loan. These are rules of thumb, not hard cutoffs — lenders
routinely stretch them (often into the mid-40s, sometimes to 50%) when you have
strong credit, cash reserves, or other “compensating factors,” and VA leans on a
residual-income test more than a flat ratio. The tool sorts your result into
plain bands: at or under 36% is generally healthy, 36–43% is a stretch many
programs still allow, 43–50% is high, and above 50% is a red flag. Treat the
program rows as “which doors are open,” not a promise of approval.
One gotcha worth repeating: DTI uses your gross income, not your
take-home pay. Using net pay is the most common mistake, and it makes your
ratio look worse than a lender will score it.
Inside the loan: how the schedule works
Once you have a price and a loan size, the next question is what that loan
actually costs you month by month and year by year. That is amortization —
the schedule that splits each payment into interest and principal.
Why your early payments are almost all interest
On a fixed-rate loan, your monthly payment stays the same, but its makeup
shifts. Early on, most of each payment is interest, because interest is charged
on a big remaining balance. As the balance shrinks, more of each payment chips
at principal. By the final years, almost the whole payment is principal.
The Loan Amortization Calculator builds the
full month-by-month schedule for any loan — mortgage, auto, or personal — so you
can see exactly where your money goes and print or export the table. It uses the
standard US convention: a simple monthly rate equal to your annual rate divided
by 12. (Some countries compound differently; this tool assumes the US monthly
method.) This is the calculator to reach for when you want the schedule itself.
When paying extra actually helps — and when it doesn’t
Because early payments are so interest-heavy, an extra dollar of principal early
in the loan erases years of future interest. That is the appeal of paying ahead.
The Mortgage Payoff Calculator lets you test
three common strategies and compare them to your current schedule, showing the
months saved and interest saved for each:
- A fixed extra each month (for example, an even $100 or $250 toward
principal).
- A one-time lump sum in a month you choose (a bonus or tax refund).
- Biweekly payments, which squeeze in the equivalent of one extra full
monthly payment per year.
The honest caveats matter here:
- The biweekly result models the common shortcut of adding one twelfth of a
payment each month. Many loan servicers hold each half-payment and only
apply it once a month, so your real-world savings can be smaller than the
clean math suggests. Ask your servicer how they actually post biweekly
payments before you sign up for a paid plan to do it.
- Any extra has to be marked “apply to principal,” or the servicer may just
treat it as your next payment and you save nothing.
- Some loans carry a prepayment penalty (rare on modern qualified mortgages,
but check your note).
- Paying down a 6% mortgage is a guaranteed 6% return. But if you carry
credit-card debt at 20%+, or you have no emergency savings, those usually come
first. The payoff tool shows the mortgage side; weigh it against the rest of
your money before you commit cash you can’t get back.
The bigger decision: rent or buy
Sometimes the most honest answer is “keep renting for now.” The
Rent vs Buy Breakeven Calculator compares the full
cost of renting against the full cost of owning over the years you plan to stay,
and finds the breakeven year — the point where buying becomes the cheaper
choice. Before that year, renting usually wins; after it, owning pulls ahead.
It does the comparison the honest way, by counting the costs buyers often
forget: closing costs to buy, property tax, insurance, maintenance, HOA, and the
cost of selling later (commissions and fees). It also counts opportunity
cost — the return your down payment and closing money could have earned if you
had invested it instead of tying it up in a house. That single factor swings the
answer more than almost anything else, which is why the tool also shows how the
breakeven moves if your assumptions about appreciation, rent growth, or
investment return are off by a percentage point.
Two honesty notes built into this tool:
- The mortgage-interest tax break is off by default. Since the 2017 tax law
raised the standard deduction, most households no longer itemize, so for them
the mortgage-interest deduction is worth nothing. The tool only counts a tax
benefit if you turn on the “I itemize” option — it will not silently inflate
the case for buying. (Its tax figures use 2024 federal standard-deduction and
SALT-cap values; tax law changes, so treat the tax line as an estimate.)
- It does not model PMI. If your down payment is under 20%, the tool flags
that your real buying cost is a bit higher than shown, because private
mortgage insurance is not included in this comparison.
A breakeven calculator is a planning aid, not a crystal ball. It cannot know
what home prices, rents, or markets will do. Run it with a few different
assumptions and look at the range of answers, not a single year.
A natural path through a home purchase looks like this:
- Price it. Start at the
Mortgage Affordability Calculator to
find a realistic home-price range for your income and down payment.
- Pressure-test approval. Run your numbers through the
Debt-to-Income Ratio Calculator to see which loan
programs your ratios fit, and what paying off one debt would do to them.
- See the real cost. Drop your loan amount and rate into the
Loan Amortization Calculator to view the
full schedule and total interest.
- Plan to pay it down. Use the
Mortgage Payoff Calculator to test whether
extra or biweekly payments are worth it for you.
- Step back. If you are still deciding, the
Rent vs Buy Breakeven Calculator checks whether
buying beats renting over the years you plan to stay.
You do not have to use all five. Pick the question you actually have, get your
estimate, and move on.
A note on the numbers. Everything here is an educational estimate, not
financial advice and not a loan offer or rate quote. Default rates, tax
rules, and PMI costs are assumptions you can change, and they are shown so you
can see them. Your actual terms depend on your lender, your credit, and your
state. For decisions this size, confirm the details with a qualified lender or
advisor.