Mortgage Basics
Mortgages make more sense when you understand the moving parts.
You do not need to learn the mortgage industry. You just need to understand the pieces that can affect your qualification, payment, flexibility, costs, and future options.
Start with the fundamentals below, then follow the links when you want a deeper explanation or want to work through your own numbers.
Understand the Basics
Quick Start
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Choose the path that sounds closest to your situation, or keep scrolling for the mortgage fundamentals.
The Fundamentals
Seven ideas explain most of how a mortgage works.
You can read straight through or jump to the part you need. Each topic explains the concept here first, then points you to a deeper answer or calculator when it would actually help.
Mortgage at a Glance
Start with the basic flow of the money.
A mortgage becomes easier to understand when you separate the purchase into a few pieces. The home has a price, you contribute a down payment, and the remaining amount is usually financed. The rate and repayment timeline then help determine the payment.
Home Price
The agreed purchase price of the property.
Down Payment
The amount you contribute toward the purchase.
Mortgage
The amount financed after the down payment.
Rate + Amortization
Two of the pieces that shape the mortgage payment.
Payment
The scheduled amount used to repay principal and interest.
The mortgage does not stay frozen in time. Your balance changes as you make payments, rates can change, your term eventually ends, and the equity in your home may become part of future decisions.
Starting the Mortgage
Home Price, Down Payment, and Mortgage Amount
The purchase price is not the amount you borrow. Your down payment reduces the amount that needs to be financed through the mortgage.
A larger down payment generally means a smaller mortgage.
The down payment can affect whether mortgage default insurance is required.
You also need to plan for closing costs separately from the down payment.
Your Payment
How a Mortgage Payment Is Shaped
Your payment depends on more than the amount borrowed. The interest rate, amortization, payment frequency, and mortgage structure all play a role.
A higher mortgage amount usually means a higher payment.
A longer amortization generally lowers the required payment but stretches repayment over more time.
Changes in interest rates can affect the payment or how quickly the balance is repaid, depending on the mortgage.
Two Timelines
Term and Amortization Are Not the Same Thing
The mortgage term is how long your current agreement lasts. The amortization is the estimated time it may take to repay the mortgage in full.
A five-year term does not mean the mortgage is repaid in five years.
You will usually have several mortgage terms during one amortization.
When a term ends, the remaining balance normally needs another mortgage agreement.
Your term should fit your real-life timeline.
Think about whether you may sell, move, refinance, access equity, or experience a major household change before the term ends.
Interest Rate
Fixed and Variable Mortgages Behave Differently
Choosing fixed or variable is about more than which rate is lower today. The two mortgage structures respond differently when interest rates change.
A fixed rate is set for the mortgage term.
A variable rate changes when the lender's prime rate changes.
Some variable mortgages change the payment when prime changes, while others keep the payment fixed and change how much goes toward principal and interest.
Not every variable mortgage works the same way.
With an adjustable-payment variable mortgage, the payment generally changes when prime changes. With some fixed-payment variable mortgages, the payment may stay the same while the portion going to interest changes. If rates rise far enough, a trigger rate or trigger point may require action.
Mortgage Features
The Rate Is Only One Part of the Mortgage
Two mortgages with similar rates can behave very differently. The features in the mortgage agreement can affect how much flexibility you have and what it may cost if your plans change.
Open mortgages generally offer more repayment flexibility, while closed mortgages usually come with restrictions on paying the balance off early.
Many closed mortgages allow annual lump-sum payments or increases to regular payments without a penalty, within the lender's limits.
Selling, refinancing, or changing lenders before the term ends can trigger a prepayment penalty.
Some mortgages can move with you to another property, subject to the lender's rules, qualification, and the new purchase.
The lowest rate is not always the lowest-cost mortgage.
A slightly lower rate can be outweighed by a large penalty, limited prepayment privileges, restrictive portability, or a mortgage that does not fit what you need to do later.
Qualification
Income Is Only One Part of What You Can Qualify For
Lenders compare your usable income with the cost of the home and your existing debts. Your down payment, credit, interest rate, and property costs can also affect the result.
GDS looks mainly at the cost of carrying the home.
TDS adds your other monthly debts.
The mortgage stress test may use a higher qualifying rate than the rate you actually pay.
Over Time
Your Mortgage Changes as You Build Equity
As the mortgage balance declines and the value of the home changes, the amount of equity you have in the property may grow.
Equity is the difference between the home's value and the amount owed against it.
It can become relevant when refinancing, moving, or restructuring debt.
Renewal is also a chance to review the mortgage rather than simply continue the same structure automatically.
The Bigger Picture
A mortgage should be compared as a complete product. The rate matters, but so do the payment structure, term, penalty calculation, prepayment privileges, portability, restrictions, and how well the mortgage fits what you may need to do later.
Where to Go Next
Go deeper only where you need to.
Follow a complete mortgage process, learn about reverse mortgages, get a quick answer to one question, or work through your own numbers.
Mortgage Guides
Follow the Complete Process
Walk through buying your first home, renewing your mortgage, or refinancing from beginning to end.
Homeowners 55+
Understand Reverse Mortgages
Learn how a reverse mortgage may allow eligible homeowners 55+ to access home equity without required regular mortgage payments, and what the costs and trade-offs can be.
Mortgage Minutes
Find a Quick Answer
Get a clear explanation of one common mortgage question in just a few minutes.
Mortgage Tools
Work Through the Numbers
Estimate payments, down payments, closing costs, qualification, and compare mortgage options.
A Note from Kiersten
You don't need to know everything about mortgages.
You just need enough information to understand the choices in front of you. My goal is to explain the important parts clearly, without burying you in industry language or information that does not apply to your situation.