Buying a home is the largest financial transaction most Americans will make. In 2026, with mortgage rates hovering between 6.5% and 7.5% and median home prices above $420,000 in many metros, the margin for error is small. This guide walks through the six decisions that decide whether a purchase works financially, using real numbers at each step.
Key Terms
- PMI, Private Mortgage Insurance: required by lenders when your down payment is less than 20%; protects the lender, not you. Costs $200-$400/month on a $400,000 loan.
- APR, Annual Percentage Rate: the true cost of borrowing, expressed as a yearly rate. Includes the interest rate plus lender fees, so it's always higher than the stated rate.
- Amortization: the schedule by which each payment splits between interest and principal. In early years, most of your payment is interest; principal paydown speeds up over time.
- Closing Costs: fees due at settlement to complete the purchase, origination fees, title insurance, appraisal, prepaid taxes, and more. Typically 2-5% of the loan amount.
- Escrow: an account held by your lender that collects monthly property tax and insurance contributions, then pays those bills on your behalf when due.
Step 1: Determine How Much House You Can Afford
Before you look at a single listing, you need a hard number, not a vague sense of comfort. The mortgage industry uses two ratios to set that number.
The 28/36 rule is the standard underwriting benchmark. Your housing costs (principal, interest, property tax, insurance, HOA) shouldn't exceed 28% of your gross monthly income. Your total debt obligations, housing plus car loans, student loans, credit cards, shouldn't exceed 36% of gross monthly income.
On a $100,000/year salary ($8,333/month gross): maximum housing payment comes to $8,333 x 0.28, or $2,333/month. Maximum total debt is $8,333 x 0.36, or $3,000/month. If you carry $500/month in car and student loan payments, your housing budget drops to $2,500 to stay under that $3,000 total, which tightens your buying range.
At a 7% interest rate on a 30-year loan, a $2,333/month principal and interest payment supports a loan of approximately $350,000. Add your down payment to get the total purchase price you can target.
Lenders also look at your Debt-to-Income ratio directly. Most conventional loans cap total DTI at 43 to 45%, and some allow up to 50% with strong compensating factors like large cash reserves or a high credit score. FHA loans have more flexibility but still enforce limits.
Use the Home Affordability Calculator to run your own numbers. Enter your gross annual income, monthly debts, estimated interest rate, local property tax rate, and expected insurance cost. The calculator applies the 28/36 rule and outputs both the maximum loan and the maximum purchase price at your target down payment.
Lenders approve you based on gross income, but you live on take-home pay. Run your own net-income stress test to make sure the monthly housing cost stays manageable after taxes, retirement contributions, and living expenses, not just on paper.
Step 2: Save Your Down Payment
The size of your down payment affects your loan amount, monthly payment, whether you pay PMI, and the interest rate you qualify for. Here are the three most common down payment tiers.
20% down, the conventional benchmark. On a $400,000 home, 20% is $80,000. This eliminates PMI entirely and typically earns the best available interest rate. You borrow $320,000 and your monthly payment is based on that smaller balance.
10% down, the middle path. On a $400,000 home, 10% is $40,000. You borrow $360,000. PMI applies until your loan balance drops below 80% of the original purchase price, which takes approximately 9 to 10 years on a 30-year amortization schedule at a normal payment pace. PMI on a $360,000 loan runs $250 to $360 a month.
3.5% down, the FHA minimum. On a $400,000 home, 3.5% is $14,000. You borrow $385,500. FHA requires Mortgage Insurance Premium: an upfront MIP of 1.75% of the loan (paid at closing or rolled into the loan) plus an annual MIP of 0.55 to 1.05% depending on loan term and LTV. For a 30-year FHA loan with less than 10% down, MIP stays for the life of the loan. It doesn't cancel automatically.
The PMI cost comparison on a $400,000 home looks like this: 20% down means $0 PMI on a $320,000 loan. 10% down runs roughly $300/month in PMI for about 9 to 10 years, a total PMI cost near $34,000. The 3.5% FHA route runs about $175/month in MIP for the loan's lifetime, close to $63,000 over 30 years if you never refinance.
Use the Down Payment Calculator to model all three scenarios. It shows the savings timelines, PMI cost over time, and the total 30-year cost difference between each approach.
Many states also offer first-time homebuyer grants and forgivable second mortgages that cover part of the down payment. Programs vary by state, income limits, and property price caps, so check your state's housing finance agency website.
Step 3: Calculate Your Monthly Mortgage Payment
The Mortgage Calculator gives you the principal and interest (P&I) component of your monthly payment, but your actual housing cost has four parts, often abbreviated as PITI: Principal, Interest, Taxes, and Insurance (homeowners plus PMI if applicable).
Sample calculation on a $320,000 loan at 7% for 30 years: P&I comes to $2,129/month (from the Mortgage Calculator). Property tax at the 1.1% average works out to $400,000 x 1.1% / 12, or $367/month. Homeowners insurance at $1,800/year comes to $150/month. PMI, if applicable at 10% down, runs ~$300/month. That puts total PITI with PMI at ~$2,946/month, and total PITI without PMI (20% down) at ~$2,646/month.
A 15-year comparison on that same $320,000 at 6.5% tells a different story: P&I comes to $2,790/month, which is $661/month more than the 30-year. Total interest paid over the life of the loan runs about $182,000, compared to roughly $446,000 on the 30-year at 7%. That's an interest savings of around $264,000 with the 15-year loan.
The lower rate on a 15-year loan (typically 0.5 to 0.75% less than a 30-year) compounds over fewer years, producing dramatic total savings for borrowers who can handle the higher payment.
Use the Mortgage Calculator to model any loan amount, term, and interest rate combination. Toggle between 15 and 30 years to see side-by-side payment comparisons.
Property taxes vary enormously by location, from 0.3% in Hawaii to over 2.5% in New Jersey. Use the Property Tax Calculator to look up your target county's effective tax rate and convert it to a monthly escrow contribution.
Step 4: Budget for Closing Costs
Closing costs are the fees charged by the lender, title company, government agencies, and service providers to complete your purchase. They're due at settlement, in addition to your down payment, and can't be rolled into a conventional loan, though they sometimes can on FHA loans.
What closing costs include:
| Cost Item | Typical Range |
|---|---|
| Loan origination fee | 0.5-1% of loan amount |
| Title search and title insurance | $700-$1,500 |
| Home appraisal | $400-$700 |
| Attorney fees (required in some states) | $500-$1,500 |
| Recording fees | $100-$300 |
| Prepaid property taxes (2-3 months) | Varies by closing date |
| Prepaid homeowners insurance (12 months) | $1,200-$2,400 |
| Prepaid mortgage interest (to month end) | Varies by closing date |
| Survey fee (if required) | $400-$700 |
| Home inspection (paid before closing) | $350-$600 |
On a $400,000 purchase with a $320,000 loan, the low estimate at 2% comes to $6,400, the high estimate at 5% comes to $16,000, and a practical planning target sits around $10,000 to $14,000.
In a buyer's market, or when a property has sat unsold for a while, you can negotiate for the seller to contribute toward your closing costs, typically up to 3 to 6% of the purchase price depending on loan type and down payment. This lowers your cash outlay at closing but may nudge the negotiated purchase price slightly.
Use the Closing Costs Calculator to generate a line-item estimate for your state, loan amount, and property value. Different states have materially different cost structures: attorney-state requirements, transfer tax rates, and title insurance premiums all vary quite a bit.
Within three business days of your mortgage application, your lender must provide a Loan Estimate with itemized closing costs. At least three business days before closing, you receive the Closing Disclosure with final figures. Compare them carefully; fees generally shouldn't increase more than 10% from estimate to final without a legitimate change-of-circumstance reason.
Step 5: Compare 15-Year vs 30-Year Mortgage
This decision carries more long-term financial weight than almost any other in the home-buying process. Run the numbers before choosing.
The core trade-off on a $350,000 loan:
| 30-Year at 7% | 15-Year at 6.5% | |
|---|---|---|
| Monthly P&I | $2,329 | $3,050 |
| Total interest paid | $488,440 | $199,000 |
| Interest savings | (baseline) | $289,440 |
| Equity at year 5 | ~$27,000 | ~$82,000 |
| Equity at year 10 | ~$61,000 | ~$196,000 |
The 30-year borrower pays nearly $290,000 more in interest over the loan term. But the 30-year also frees up $721/month in cash flow, money that could go toward retirement accounts, a child's education, or an emergency fund.
The case for the 30-year: a lower required payment protects cash flow during a job loss or income disruption. The payment difference, if invested at a 7% annual return over 15 years, can outpace the interest savings. And you keep the flexibility to make extra payments when income allows, without being locked into them.
The case for the 15-year: it's a forced savings mechanism, since you build equity faster by design. The rate typically runs 0.5 to 0.75% lower, which compounds the savings further. You're mortgage-free 15 years sooner, which matters if you're in your 40s or 50s. And the lower total interest cost is guaranteed, unlike investment returns.
A hybrid strategy works too: take a 30-year loan for its lower required payment, but make additional principal payments each month targeting the 15-year payoff schedule. If your income drops, you can revert to the minimum payment without any default risk. Use the Mortgage Payoff Calculator to work out exactly how much extra to pay each month to hit your target payoff date.
Step 6: Plan Your Refinancing Strategy
Buying isn't a one-time decision. The rate environment and your financial situation will both shift over your ownership period. Knowing when refinancing makes sense keeps you from either leaving money on the table or churning loans unnecessarily.
Refinancing costs money, typically $3,000 to $7,000 in closing costs, so you need to recoup those costs through monthly savings before you break even. The formula: break-even months equals closing costs divided by monthly payment savings.
For example, say you refinance a $300,000 balance from 7.25% to 6.25%. New closing costs run $5,500. Monthly saving comes to $190. Break-even works out to 5,500 / 190, or 29 months. Plan to stay more than 29 months and refinancing makes financial sense.
The old rule of thumb was to refinance once you could drop your rate by a full point. In 2026, with higher loan balances, a drop of 0.75% can produce meaningful savings worth the transaction costs. The break-even calculation is more reliable than any fixed threshold.
A few situations point toward refinancing: your credit score has improved significantly since your original loan, market rates have dropped 0.75% or more below your current rate, you want to shorten your term as your income has grown, you want to eliminate PMI once you have 20% equity (especially if home values have appreciated), or you need to cash out equity for major renovations.
A few situations argue against it: you plan to sell within 2 to 3 years, before you'd break even. You're 20-plus years into a 30-year loan, where the remaining balance is mostly principal, so a lower rate saves less than it looks like it would. Or the closing costs would eat into cash reserves you need for emergencies.
When rates fall, refinancing demand spikes and lenders get busy; applications can take 45 to 60 days. Apply early in a rate-drop cycle rather than waiting for the absolute bottom.
The Numbers at a Glance
For a $400,000 home purchase in 2026:
| Scenario | Down Payment | Loan | Rate/Term | P&I | Est. Total PITI |
|---|---|---|---|---|---|
| 20% Conventional | $80,000 | $320,000 | 7% / 30yr | $2,129 | ~$2,646 |
| 10% Conventional | $40,000 | $360,000 | 7.125% / 30yr | $2,425 | ~$3,242 (with PMI) |
| 3.5% FHA | $14,000 | $385,500 | 6.875% / 30yr | $2,532 | ~$3,424 (with MIP) |
| 20% Conventional | $80,000 | $320,000 | 6.5% / 15yr | $2,790 | ~$3,307 |
Total PITI estimates include 1.1% property tax, $1,800/year insurance, and applicable PMI/MIP. Use the Mortgage Calculator to customize for your exact location and loan parameters.
Practical Timeline
Most home purchases take 60 to 120 days from the decision to buy to keys in hand. A realistic sequence looks like this.
Months 1 through 3: check affordability, review your credit report, pay down debts to improve DTI and credit score, and assemble your down payment funds. Months 3 through 4: get pre-approved, not just pre-qualified, from 2 to 3 lenders, and compare Loan Estimates on APR rather than just rate. Months 4 through 6: house hunt with your agent, submit offers, and negotiate price and seller concessions. Once under contract, expect 30 to 45 days for the home inspection, appraisal, loan underwriting, and title search. Then closing day: sign documents, wire funds, receive keys.
Clean credit with no recent large deposits or job changes speeds things up, as does fully documented income (W-2 employees tend to move faster than self-employed buyers) and a pre-approval from a reputable lender with local market experience.
What stalls the process: an appraisal coming in below purchase price, which triggers renegotiation, title issues like unpaid liens or boundary disputes, underwriting conditions that require additional documentation, and rate locks expiring if closing gets delayed.
Tools for Every Step
- Home Affordability Calculator: what price range fits your income and debts
- Down Payment Calculator: 20% vs 10% vs 3.5% total cost comparison
- Mortgage Calculator: monthly P&I for any loan amount, rate, and term
- Closing Costs Calculator: line-item closing cost estimate by state
- Mortgage Payoff Calculator: how extra payments change your payoff date and total interest
- Property Tax Calculator: annual and monthly property tax by location