MortMetrix Guides

Mortgage Guides: Learn the Math Behind Your Mortgage

Every guide answers a real mortgage question and shows the math behind the answer. Start with the fundamentals, understand the numbers, and see how the calculations apply to your own mortgage.

Mortgage Payoff

Everything you need to understand, plan and track paying your mortgage off ahead of schedule.

Extra Mortgage Payments

What an extra $100, $200 or $1,000 a month actually does — quantified, with the amortization math behind it.

Amortization

How the split between interest and principal is calculated, and how to read your own schedule.

Mortgage Interest

How much interest a mortgage really costs over its life, and the three levers that change the total.

Mortgage Equity

What home equity is, how each payment builds it, and how extra principal speeds it up.

Loan Types & Getting Approved

PMI, FHA, VA, USDA, jumbo loans, down payments and affordability — the decisions that come before you have a mortgage at all.

How Much Should You Put Down on a House?

Every down payment option from 0% to 20%, side by side, with the monthly cost of each.

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20% Down Payment vs. PMI: Which Costs You Less?

Buying now with PMI versus waiting to save 20% — and why appreciation can move the target faster than you save.

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What Is an Escrow Account and How Does It Work?

Why a "fixed" payment still changes each year, how shortages are recovered, and when you can skip escrow.

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What Is PMI (Private Mortgage Insurance)?

What PMI costs by down payment size, how it's calculated, and the two ways it legally comes off your loan.

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Fixed-Rate vs. Adjustable-Rate Mortgage (ARM): What's the Difference?

What a 5/1 ARM saves up front, and what a single capped adjustment can cost you afterwards.

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FHA vs. Conventional Loan: Which Is Right for You?

Five ways to finance the same home compared — and why your credit score, not the headline rate, usually decides which loan wins.

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VA Loans Explained: Eligibility, Benefits, and How They Work

Zero down, no mortgage insurance ever, and a one-time funding fee — what a VA loan actually costs across five scenarios.

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What Is a Jumbo Loan and When Do You Need One?

The 2026 conforming limits, what jumbo underwriting actually demands, and three ways to avoid needing one.

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Mortgage Pre-Approval vs. Pre-Qualification: What's the Difference?

What each one actually requires, how long it takes, and why only one of them gets an offer taken seriously.

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What Is Debt-to-Income (DTI) Ratio?

Front-end vs. back-end DTI, what actually counts as debt, and the real limits by loan program.

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USDA Loans: Do You Qualify for 0% Down?

Zero down for moderate-income buyers in eligible areas — the income limits, the guarantee fee, and how it compares to VA and FHA.

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Mortgage Closing Costs Explained: What to Expect

A full line-item breakdown of $12,000 in closing costs, who pays what, and four ways to reduce the total.

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How Much House Can I Afford?

The 28/36 rule applied to a real budget — and why $500 of monthly debt costs $70,000 of buying power.

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Refinancing & Rate Moves

Refinancing, recasting, cash-out and points — when a rate or balance move actually pays for itself.

Run your own numbers

Track your actual mortgage

The figures on this page are an example loan. MortMetrix builds your full amortization schedule from your real balance, rate and term, then shows exactly what any extra payment does to your payoff date, lifetime interest and equity.

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