Mortgage Basics for the Buy vs Rent Decision

Most mortgage calculators show only principal and interest — but your actual monthly payment is larger. The standard components are summarized in the acronym PITI: principal, interest, taxes, and insurance. On a $400,000 loan at 7% for 30 years, principal and interest alone total $2,661 per month. Add property taxes at a 1.2% effective rate ($400/month) and homeowners insurance ($175/month) and the actual payment is closer to $3,236 — 21% more than the base figure.

Property taxes are collected monthly by most lenders and held in escrow, then paid directly to the local taxing authority on your behalf. The tax rate varies enormously by location — from under 0.4% of home value in Alabama to over 2% in New Jersey and Illinois. Insurance premiums similarly vary by state, coverage, and risk profile. The PITI breakdown guide walks through each component with dollar examples at different price points.

If your down payment is below 20% on a conventional loan, private mortgage insurance (PMI) is added on top of PITI. PMI typically costs 0.5% to 1.5% of the loan amount annually — another $83 to $250 per month on a $200,000 loan. The PMI guide explains how it is calculated, when it cancels, and how to remove it earlier than the scheduled date.

Private mortgage insurance protects the lender — not you — in the event of default. It is required on conventional loans with less than 20% down and is priced based on your credit score, loan-to-value ratio, and loan type. A buyer with a 720 credit score putting 5% down on a $400,000 home might pay 0.6% in PMI annually, or $152 per month. The same buyer with a 680 score might pay 0.9% — $225 per month for the same protection on the same property.

Conventional PMI can be cancelled once your equity reaches 20% of the original purchase price. Under the Homeowners Protection Act, you can request cancellation when your balance drops to 80% LTV, and lenders must automatically cancel it at 78% LTV based on the original amortization schedule. You can also reach 20% equity faster through appreciation — in that case, a new appraisal can support an early cancellation request. The PMI removal guide covers all three strategies.

FHA loans work differently. FHA mortgage insurance includes an upfront premium (1.75% of the loan) plus an annual premium of 0.55% to 1.05% depending on term and LTV. For most borrowers who put less than 10% down, FHA mortgage insurance is permanent — it does not cancel at 20% equity. This is a meaningful long-term cost that makes FHA loans more expensive than they initially appear for buyers who build equity quickly. The FHA vs conventional guide models total cost over 5, 10, and 20 years.

The 30-year mortgage dominates the U.S. market for one reason: lower monthly payments. Spread over 360 payments instead of 180, the same loan amount produces a significantly smaller required monthly commitment. But that lower payment comes at a steep long-term cost. On a $350,000 loan at 6.5%, the 30-year payment is approximately $2,213 per month. The 15-year payment is $3,054 — $841 more. Over the life of the loan, the 30-year borrower pays roughly $447,000 in interest. The 15-year borrower pays approximately $200,000 — a difference of $247,000.

The 15-year loan also carries a lower rate in most market environments — typically 0.5% to 0.75% below the 30-year rate — which compounds the savings. For buyers who can comfortably afford the higher payment, the 15-year mortgage builds equity faster, pays off sooner, and saves dramatically on total interest. The tradeoff is reduced monthly cash flow flexibility: if income drops, a $3,000 payment is harder to cover than a $2,200 one. The 15 vs 30-year guide includes a full break-even and equity comparison.

Amortization is the process of paying off a loan through equal periodic payments that cover both interest and principal. The critical detail most borrowers miss: early payments are overwhelmingly interest. On a $400,000 30-year mortgage at 6.5%, your first payment includes approximately $2,167 in interest and only $494 in principal. You are 15 years into the loan before the split shifts to roughly half-and-half. By year 25, most of each payment is principal — but by that point, you have paid over $330,000 in interest.

Extra principal payments made early in the loan are disproportionately valuable because they reduce the balance on which future interest is charged. An extra $200 per month applied to principal starting in year one reduces the loan term by roughly 5 to 6 years and saves over $85,000 in interest on a $400,000 loan at 6.5%. The amortization guide models the exact impact of lump-sum and recurring extra payments at different stages.

Refinancing replaces your existing mortgage with a new loan — typically at a lower rate, shorter term, or different structure. The core metric is break-even: how many months of lower payments does it take to recoup the closing costs of the new loan? Refinance closing costs typically run 2% to 3% of the loan amount. On a $350,000 loan, that is $7,000 to $10,500. If the new loan saves $250 per month, the refinance break-even point is 28 to 42 months. If you plan to stay in the home beyond that, the refinance makes financial sense.

Rate-and-term refinances are the most straightforward: you refinance to capture a lower rate or shorter term without changing the loan amount. Cash-out refinances borrow against equity and reset the loan balance higher — they can make sense for major renovations but extend your payoff timeline and increase interest cost. Refinancing from FHA to conventional can also eliminate permanent FHA mortgage insurance once you reach 20% equity, which is often worth the closing costs even without a rate improvement. The refinance strategy guide includes a break-even calculator and scenario comparisons.

Payment examples in this guide use fixed-rate loan assumptions with stated interest rates, standard amortization schedules, and nationally representative property tax and insurance estimates. Property tax rates are sourced from Tax Foundation and Lincoln Institute of Land Policy state-level effective rate data. PMI rate ranges are based on published Fannie Mae and Freddie Mac pricing grids. FHA premium rates reflect current HUD guidance.

All dollar figures are illustrative and based on stated loan amounts and assumptions. Actual mortgage payments, rates, and insurance costs vary by lender, credit profile, property location, and loan program. This guide is updated annually to reflect current loan program requirements and rate environments. The mortgage calculator linked throughout uses user-supplied inputs and does not predict future rate movements.

Every mortgage cost covered in this guide feeds directly into the true cost of owning vs renting. PMI, property taxes, insurance, and the interest-heavy nature of early amortization all increase the effective monthly cost of buying above the number most calculators show. When those costs are fully accounted for, the rent vs buy break-even point often extends to 6–9 years rather than the 3–5 years buyers initially assume.

The practical implication: before deciding to buy, model the full homeownership cost inputs — not just the mortgage payment. Include PMI (if applicable), property tax rate, insurance, and expected maintenance. Then compare that total monthly cost against what you would pay in rent. The buy vs rent calculator does this comparison automatically and shows the cumulative cost curves over time.