The math before the paperwork.

A mortgage rate is not one number a lender picks. It starts with the bond market, specifically mortgage-backed securities, which moves every day and sets the floor everybody prices from. On top of that floor, your file gets priced by its own risk: credit score, loan-to-value (how much you borrow against what the house is worth), whether you will live in the home, whether it is a single family house or a condo or a multi-unit, and how the loan amount compares to your county's conforming limit.

Then come the choices you control. Term length changes the price. Discount points are prepaid interest that buy the rate down. Lock length matters because a 60-day lock costs more than a 15-day lock, since the lender is carrying the risk longer.

Two files submitted the same morning with the same lender can price a half point apart for reasons that have nothing to do with negotiation. Your neighbor's rate is not your rate and comparing them tells you nothing.

A prequalification is an estimate. You tell a loan officer your income, your debts and your down payment, they run the arithmetic, and they hand you a number. Nothing has been verified. It is useful for planning and almost useless in a competitive offer.

A preapproval is a formal evaluation. We collect documents, pull credit, calculate income the way an underwriter will calculate it, and where the file warrants it we put it in front of an underwriter before the letter leaves the office. The letter then states what is actually done and what conditions remain.

In Montana markets where homes go pending in roughly nineteen days, the difference decides whether a listing agent takes your offer seriously or sets it aside for the buyer whose financing looks finished.

The number people quote each other is usually principal and interest only. Your real payment is PITI: principal, interest, taxes and insurance. Principal reduces the balance. Interest is the cost of borrowing. Taxes are your county property taxes. Insurance is your homeowners policy.

Add mortgage insurance if your down payment is under twenty percent, and add HOA dues if the property has an association. On a Montana acreage that number can also include a separate wildfire or outbuilding rider.

Most loans collect taxes and insurance monthly into an escrow account, a holding account the servicer uses to pay those bills when they come due. It is why your payment can change year to year even on a fixed-rate loan: the rate did not move, your tax bill or your premium did.

Debt-to-income, or DTI, is every monthly debt payment divided by your gross monthly income, before taxes. Underwriters use it to decide whether the new payment fits.

Worked example. You earn $8,000 a month gross. You pay $520 on a truck, $180 on a student loan and $150 in credit card minimums, so $850 of existing debt. The house you want carries a $2,300 PITI payment. Total debt is $3,150. Divide by $8,000 and your DTI is 39.4 percent.

Groceries, utilities, phone bills and gas are not counted. Only debts that show on credit plus the housing payment, along with items like child support or alimony. Many programs run to 45 or 50 percent DTI with strong compensating factors such as reserves or a high credit score, so a number over 43 is not automatically a no.

For a buyer, closing costs typically run 2 to 5 percent of the loan amount. They come in categories. Lender fees cover underwriting and origination. Third-party fees cover the appraisal, credit report, flood certification and, in Montana, sometimes a well and septic inspection. Title and escrow fees cover the title search, lender's title policy and the closing itself. Government fees cover recording and any transfer taxes.

Then come prepaids, which are not fees at all: prepaid interest from your closing day to the end of that month, the first year of homeowners insurance, and the initial escrow deposit for taxes and insurance. Prepaids feel like a cost but they are money you would owe anyway.

What is negotiable: lender fees, points, and which side pays title. What is not: recording fees, appraisal cost and taxes. You get a Loan Estimate within three business days of applying that itemizes all of it, and a Closing Disclosure three business days before closing. Compare those two documents line by line and ask about any line that moved.

Mortgage insurance exists to protect the lender, not you, when the down payment is small. It is the price of buying before you have twenty percent saved, and for most buyers it is a fair trade against another two years of rent and appreciation.

On a conventional loan, PMI applies until you reach twenty percent equity. It is priced by credit score and loan-to-value, and it is removable. It cancels automatically at 78 percent loan-to-value on the original schedule, and you can request removal at 80 percent, often sooner with an appraisal if values moved.

FHA is different. FHA mortgage insurance has an upfront premium plus an annual premium, and on most current FHA loans with the minimum down payment that annual premium stays for the life of the loan. It does not fall off at twenty percent equity.

That single difference changes the long-term math. A slightly higher conventional rate with cancellable PMI often costs less over seven years than a lower FHA rate with permanent insurance. Ask for both scenarios side by side, in dollars, before you choose.

A discount point is prepaid interest. One point costs one percent of the loan amount and buys the rate down by some amount, often about a quarter percent, though the exact tradeoff changes daily with the market.

The math is a break-even. On a $400,000 loan, one point costs $4,000. If that point drops the payment by $62 a month, you recover the cost in roughly 65 months, a little over five years.

Points are worth it if you are certain you will hold the loan well past the break-even and you have cash beyond your reserves. They are not worth it if you might sell or refinance inside that window, if the money would be better used as down payment to clear a PMI or loan-to-value threshold, or if paying them leaves you thin on reserves after closing.

Reserves are the liquid money you still have after closing, counted in months of your new housing payment. If your PITI is $2,400 and you have $14,400 left in the bank after the down payment and closing costs, you have six months of reserves.

Underwriters want reserves because they answer the question that credit history cannot: what happens the month something goes wrong. Retirement accounts usually count at a discount, often sixty to seventy percent of the vested balance, because withdrawal has a cost.

Some loans require zero reserves. Jumbo files commonly want six to twelve months. Investment property and multi-unit files want more. Reserves are also one of the strongest compensating factors when DTI is stretched, so do not drain every account to make a larger down payment without asking how it affects approval.

A rate lock is the lender's commitment to honor a rate for a set number of days regardless of what the market does. It protects you from rates rising between application and closing. It does not let you take advantage if rates fall.

Lock length is priced. A 30-day lock is cheaper than a 60-day lock, and a lock on a build that will not close for eight months is an extended lock with a real cost, sometimes paid upfront.

If closing slips past the expiration you need an extension, which typically costs a fraction of a point per week. If the market improves substantially, some programs offer a one-time float-down, with conditions. Ask what the extension policy costs before you lock, not the week you need it.

Have these ready and the file moves twice as fast: two years of federal tax returns with all schedules, your most recent 30 days of pay stubs, two years of W-2s, two months of statements for every account you will use for down payment or reserves, a government photo ID, and your two-year residence history with landlord contact information if you have been renting.

If any of your down payment is a gift, we need a signed gift letter and a paper trail showing the money leaving the donor's account and arriving in yours. Season the funds early; unsourced deposits are the single most common cause of a delayed closing.

If you are self-employed, add two years of business returns, a year-to-date profit and loss statement, business bank statements, and your K-1s or 1099s. If you are using bank statement qualifying instead, expect twelve to twenty-four months of statements and an expense factor.

If you are a veteran, add your DD-214 and your Certificate of Eligibility. On rural or acreage properties, add well and septic records, any shared well agreement, and documentation of recorded legal access.

Conforming limits and jumbo. Most Montana counties sit at the 2026 baseline conforming limit. Gallatin County is high-cost with a higher ceiling. One dollar over your county's limit and the loan becomes a jumbo, which is a different underwriting standard: more reserves, tighter DTI, often a second appraisal. Knowing where that line falls in your county before you write an offer is worth more than a quarter point on the rate.

Wells and septic. If the property is not on city water and sewer, the appraiser and the underwriter both want documentation: a well flow test and potability test on most programs, and a septic that is either permitted with the county or has an inspection showing it functions. FHA, VA and USDA are stricter here than conventional.

Shared wells. Common in the Bitterroot and the Flathead. Most programs require a recorded shared well agreement that covers maintenance cost allocation and access rights, and that binds future owners. A handshake with a neighbor is not financeable. This is fixable, but it takes weeks, so start it the day you go under contract.

Legal access. The road has to be recorded. A driveway that crosses a neighbor's ground on a verbal understanding is a title problem, not a lending problem, and it stops the loan. Ask the title company early whether access is recorded and whether the easement runs with the land.

Excess acreage. Residential financing values the house and a typical homesite. When you buy forty acres, the appraiser needs comparable sales with similar acreage, and value attributable to land far beyond the local norm may be limited or excluded. Outbuildings often carry little appraised value even when they cost real money to build.

Unpermitted structures. The shop that was framed without a county permit does not necessarily kill the deal, but it cannot be given value as finished living space, and on some programs it has to be shown as safe and structurally sound. In counties without building permit jurisdiction, we document it differently. Tell us before the appraisal, not after.

Agricultural classification. Land taxed as agricultural changes the tax picture and can change the program that fits. Some parcels with active ag use or a grazing lease need a different structure entirely.

Wildfire insurability. In parts of the Bitterroot, the Seeley-Swan and the wildland-urban interface, the loan is not the hard part; the insurance is. Get a homeowners quote in the first week of your inspection period. A file that cannot get bound coverage cannot close, no matter how strong the borrower.

The building season. Montana frames from roughly April to October. A construction loan that funds in September fights the frost. Lock strategy, draw schedule and contingency need to be built around that reality, and a build that misses its window is the most expensive mistake in Montana lending.