Most home buying guides bury you in jargon before they tell you anything useful. This one doesn't. If you're trying to figure out what you can actually afford, whether you really need 20% down (you don't), or what's going to blindside you at closing, this covers it - with three live calculators built directly into the guide so you can run your own numbers without leaving the page.
Step 1: Figure Out What You Can Actually Afford
Before you fall in love with a listing, you need a real number - not a guess, not what a Zillow banner ad thinks you can spend, an actual figure based on your income and debts.
Lenders generally lean on what's known as the 28/36 rule: your housing payment shouldn't eat more than 28% of your gross monthly income, and your total debt - housing plus car payments, student loans, credit cards - shouldn't cross 36%. Whichever of those two limits is tighter for you is the one that actually caps your home price.
The tricky part is that this isn't just about principal and interest. Property tax and insurance eat into that 28% too, and they scale with the home's price - so a naive "how much loan can I afford" calculation tends to overstate your real number. The calculator below solves for this properly: it applies the 28/36 rule and works backward through the full payment - principal, interest, tax, insurance, even PMI if it applies - to give you an honest price ceiling instead of an optimistic one.
Home Affordability Calculator
Live| Principal & interest | $1,756.15 |
| Property tax (monthly) | $356.53 |
| Insurance (monthly) | $103.99 |
| PMI (monthly) | $0.00 |
| Total monthly payment (PITI) | $2,216.67 |
Step 2: The 20% Down Payment Thing Is Mostly a Myth
Here's a stat that surprises a lot of first-time buyers: the median down payment for first-time buyers in the US is around 9-10%, not 20%. Repeat buyers put down more (often 19-23%), but that's usually because they're rolling equity from a previous home into the new one, not because 20% is some hard requirement.
The real minimums, by loan type:
- Conventional loans: as low as 3% for qualified buyers
- FHA loans: 3.5% with a credit score of 580+ - see exactly how FHA's mortgage insurance premium (MIP) affects your payment with the FHA Mortgage Calculator
- VA loans: 0% down for eligible veterans and service members
- USDA loans: 0% down in eligible rural and suburban areas
So why does the "20%" number stick around? Two real reasons: it lets you skip private mortgage insurance (PMI), and it usually gets you a slightly better rate. Both are genuine advantages - but neither means a smaller down payment is a mistake, especially if home prices in your market are climbing faster than you can save. Waiting two extra years to hit 20% on a home that's appreciating 4-5% a year can easily cost you more than the PMI would have. Run your own numbers with the Down Payment Calculator to see exactly how different down payment percentages change your loan amount and monthly payment.
Step 3: Your Real Monthly Payment Isn't Just "Principal and Interest"
This is where a lot of budgets quietly fall apart. The number a mortgage rate calculator spits out - principal and interest - is not what actually leaves your bank account every month. Lenders call the full picture PITI:
- Principal - paying down what you borrowed
- Interest - the cost of borrowing it
- Taxes - property tax, billed by your county or city
- Insurance - homeowners insurance, sometimes flood or earthquake insurance depending on where you live
If your down payment is under 20% on a conventional loan, add a fifth line: PMI, which typically runs somewhere between 0.3% and 1.5% of the loan amount per year until you build enough equity to drop it. It's not a scam or a junk fee - it's what lets you buy with less than 20% down in the first place - but it's a real monthly cost that a bare "mortgage calculator" often leaves out entirely.
Try the full PITI breakdown below, or check specifically whether PMI applies to your situation with the PMI Calculator.
PITI Calculator
Live| Principal & Interest | $1,896.20 |
| Property tax (monthly) | $300.00 |
| Insurance (monthly) | $100.00 |
| Total monthly PITI | $2,296.20 |
Step 4: The Closing Costs Nobody Warns You About
You've saved for the down payment. Good. Now save a bit more, because closing costs - the fees for actually finalizing the purchase - typically run 2% to 5% of the home's price, due upfront, on top of your down payment.
These fees cover things like the loan origination fee, appraisal, title insurance, attorney fees (in some states), and prepaid items like the first chunk of property tax and insurance. On a $400,000 home, that's realistically $8,000 to $20,000 - money a lot of first-time buyers don't budget for until it's suddenly due. Estimate your actual number with the Closing Cost Calculator before you're staring at a settlement statement wondering where an extra $12,000 came from.
Step 5: Should You Even Buy Right Now?
This one gets skipped in most guides, probably because "maybe don't buy" doesn't sell much. But it's worth asking honestly: in your specific market, at your specific numbers, is renting actually cheaper right now?
The comparison isn't just "rent vs. mortgage payment" - it needs to weigh what you'd have if you invested your down payment instead, against the equity you build by owning, plus maintenance costs that renters simply don't pay (a new roof doesn't call your landlord when you own the place). The Rent vs. Buy Calculator runs both sides of that math side by side so the decision is based on your actual numbers, not a general vibe about renting being "throwing money away" (it often isn't, depending on the market).
Step 6: Shopping for the Mortgage Itself
Once you know your price range and you've decided buying makes sense, the mortgage shopping part is honestly the most mechanical step - which is a relief after everything above.
As of spring 2026, the national average for a 30-year fixed-rate mortgage sits around 6.1%, though your actual rate depends heavily on credit score, loan type, and down payment size. Even a small rate difference matters more than people expect over 30 years - a 0.5% difference on a $350,000 loan works out to tens of thousands of dollars in extra interest over the life of the loan. Compare exact payment scenarios below before you commit to a lender's first offer.
One thing worth asking every lender about: buying "points" - paying an upfront fee to lock in a lower rate for the life of the loan. Whether that trade makes sense depends entirely on how long you plan to keep the loan; the Mortgage Points Calculator shows the exact break-even point where the upfront cost pays for itself.
Mortgage Calculator
LiveAfter You Buy: What Happens Next
Buying the home isn't the finish line - a few things are worth keeping on your radar afterward:
Refinancing: if rates drop meaningfully after you buy, or your credit improves, refinancing can lower your rate or shorten your term. Check whether it's worth it with the Refinance Calculator - the math depends on how long you plan to stay in the home versus the closing costs of refinancing itself.
Tapping your equity: once you've built up equity, a cash-out refinance or home equity line lets you borrow against it for renovations, debt consolidation, or other large expenses. See how much you could access with the Cash-Out Refinance Calculator or the Home Equity Calculator.
Paying it off faster: even small extra payments toward principal can shave years off a 30-year loan and save a genuinely large amount in interest. The Mortgage Payoff Calculator shows exactly how much time and interest an extra $100 or $200 a month actually saves. A related trick worth knowing: switching to biweekly payments (half your monthly payment, every two weeks) effectively sneaks in one extra full payment a year without feeling like a stretch - see the exact effect with the Biweekly Mortgage Calculator.
Frequently asked questions
Do I really not need 20% down to buy a house?
Correct - conventional loans allow as little as 3% down for qualified buyers, and FHA loans allow 3.5%. The median first-time buyer actually puts down around 9-10%. A 20% down payment has real benefits (no PMI, often a better rate), but it isn't a requirement.
What's the difference between a mortgage payment and PITI?
A basic mortgage calculator usually shows only principal and interest. PITI adds property tax and homeowners insurance, and PMI if your down payment is under 20% - which together can add hundreds of dollars to what a bare P&I number suggests.
How much should I budget for closing costs?
Typically 2% to 5% of the home's purchase price, due upfront alongside your down payment. On a $400,000 home, that's roughly $8,000 to $20,000.
Is it better to rent or buy right now?
It depends entirely on your specific market and numbers - there's no universal answer. Comparing what you'd have if you invested your down payment instead, against the equity and costs of owning, is the only way to answer it for your situation.
Should I get a fixed-rate or adjustable-rate mortgage (ARM)?
A fixed rate never changes for the life of the loan, giving you a predictable payment. An ARM typically starts with a lower rate for an initial period (often 5, 7, or 10 years), then adjusts periodically based on market rates - which can go up or down. ARMs can make sense if you're confident you'll sell or refinance before the adjustable period starts; otherwise the predictability of a fixed rate is worth more to most buyers than the initial discount.
How much does my credit score actually affect my rate?
Substantially - lenders use credit score tiers to price risk, and the gap between a "good" and "excellent" score can easily be half a percentage point or more on your rate. On a $350,000 loan, that difference alone can mean tens of thousands of dollars in extra interest over 30 years, which is why improving your score even modestly before applying is often worth the wait.
What's the difference between pre-qualification and pre-approval?
Pre-qualification is a quick, informal estimate based on self-reported numbers - useful for a rough sense of your range, but not much else. Pre-approval involves an actual credit check and documentation review by a lender, resulting in a real conditional commitment. Sellers in competitive markets generally expect pre-approval, not just pre-qualification, before taking an offer seriously.
The Short Version
Figure out your real affordable price first (not the bank's optimistic pre-approval number), don't assume you need 20% down, budget for PITI and closing costs separately from the sticker price, and actually check whether renting beats buying in your specific market before you commit. Every calculator on this page is free, runs in your browser, and takes your real numbers - not someone else's example.