Mortgage Rate Guides

Straight, neutral explainers on how mortgage rates work — written by someone who spent two decades inside the business. No lead forms, no "get pre-approved," no spin. Just the mechanics, so you can read the market for yourself.

• Mortgage glossary
  Plain-English definitions of the terms on every rate sheet — APR, points, par, LTV, PMI, DTI and more.
• How we source our rates
  Exactly where our numbers come from, what we do and don't collect, and why we're a monitor, not a scraper.
• How mortgage rates are set
  Why your rate isn't the headline rate — the bond market, your file, and the lender's margin, explained.
• What OBMMI is, and why we benchmark to it
  The Optimal Blue index behind our headline number — built from real locked rates, daily. How it differs from the Freddie Mac weekly survey, and from your quote.
• Why the headline rate isn't yours
  The gap between an advertised or survey rate and the number you'll actually be quoted — and the four things that move your personal rate off the headline.
• How to read the RallyRates Index
  A guide to our own data: the two layers (OBMMI benchmark vs. our tracked-lender panel), why we average only par rates, and the Receipt behind every figure.
• APR vs. interest rate
  The difference that actually costs you money — and when APR is (and isn't) the right number to compare.
• Are discount points worth it?
  What a point really buys, how to find your break-even, and why we benchmark the par (zero-point) rate.
• How to read a lender rate sheet
  An insider's tour of the document behind your quote — base price, add-ons, lock pricing, and the catches.
• How to compare Loan Estimates
  The apples-to-apples method for the standardized LE — which page, which box, and the one number where lenders truly differ.
• Rate locks explained
  When to lock and when to float, what a lock really costs, and how float-downs and extension fees actually work.
• Conforming vs. jumbo loans
  The 2026 loan limit, why the rate can move at the line, and why a jumbo isn't automatically more expensive.
• Temporary buydowns (2-1, 3-2-1)
  How a 2-1 buydown really works, who pays for it, and why it's not the same as buying down your rate with points.
• ARM vs. fixed-rate mortgages
  How an adjustable rate is built — intro period, index plus margin, and the caps — and when an ARM is rational vs. a trap.
• When does refinancing make sense?
  The break-even rule, why the '1% drop' myth is wrong, the 30-year reset trap, and non-rate reasons to refinance.
• PMI — and how to get rid of it
  The automatic 78% and requested 80% cancellation rules, using an appraisal to cancel early, and why FHA insurance is different.
• Closing costs: who pays what
  The lender, third-party and prepaid buckets (2-5% of the loan), why prepaids aren't really costs, and what's negotiable.
• How your credit score moves your rate
  Why the same house and lender can quote two rates — the score-driven add-ons, the tier breaks, and how to cross one before you apply.
• Escrow accounts explained
  How the servicer collects taxes and insurance, the annual analysis, and why a tax or insurance hike makes your 'fixed' payment jump.
• How much down payment do you need?
  The real minimums (3% / 3.5% / 0%), why 20% is a PMI threshold not a rule, how gift funds work, and why not to drain your reserves.
• Conventional vs. FHA vs. VA vs. USDA
  How the four main loan types differ on down payment, mortgage insurance, and who qualifies — and which one fits your file.
• Debt-to-income: how much can you borrow?
  Front-end vs. back-end ratios, the 28/36 guideline (and how underwriting stretches it), and the fastest ways to lower your DTI.
• Pre-approval vs. pre-qualification
  Why a pre-qual is just an estimate, a pre-approval is a vetted commitment, and which one a seller actually respects.
• The appraisal process
  Why lenders require it, how comps set the value, and your options when it comes in below your contract price.
• HELOC vs. cash-out refinance
  Two ways to tap equity — and why the rate on the first mortgage you already have usually decides which one wins.
• What makes up your payment (PITI)
  Principal, interest, taxes and insurance — which parts your rate sets, which it doesn't, and why a 'fixed' payment can change.
• The mortgage process, start to finish
  The whole journey mapped: pre-approval, offer, Loan Estimate, lock, appraisal, underwriting and closing — and where your leverage really is.
• Assumable mortgages
  How taking over a seller's FHA, VA or USDA loan at its original rate works — and why you have to finance the equity gap.
• A first-time buyer's guide
  The short version of what matters: real down-payment minimums, the two numbers that set your budget, and getting pre-approved first.

By L.W. Martin, Founder — 20 years in the mortgage business, including 15 running his own brokerage. About → · Updated September 2026.