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Personal Finance · Foundations

Mortgages

9 min read 5 practice questions
8 key termsSourcesReport an error
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On this page 9 sections
  1. In 30 seconds
  2. Why this matters
  3. The college version
  4. Eli explains
  5. Worked example
  6. Key takeaway
  7. Quick check
  8. Study tools
  9. Sources & references

In 30 seconds

A is a loan used to buy or refinance a home, and the home itself is the collateral: if the borrower stops repaying, the lender can take the property. The buyer pays a up front and repays the rest — plus interest — in monthly payments over a term of typically 15, 20, or 30 years, through a process called . The monthly payment can also bundle property taxes, homeowners insurance, and, with a small down payment, .

Why this matters

For most households, buying a home is the largest purchase they will make, and the mortgage that finances it is the largest loan they will ever take — an inference that follows from the long terms and the size of the amounts involved. Because a mortgage runs for decades, small differences in rate, term, and down payment translate into tens of thousands of dollars over the life of the loan. The same concepts — principal, interest, amortization, escrow — reappear in later economics and finance courses and in everyday decisions about refinancing or selling. Understanding how a mortgage is structured is what separates reading an offer from understanding what it costs.

The college version

A loan for a home, secured by the home

A mortgage is an agreement between a borrower and a lender that allows the borrower to borrow money to purchase or refinance a home, and gives the lender the right to take the property if the money is not repaid. That working definition, drawn from the Consumer Financial Protection Bureau's mortgage key-terms page, captures the two things that make a mortgage distinctive: it exists to buy a home, and the home backs the debt. The Corporate Finance Institute describes a mortgage as a loan secured by real property, and the lender's lien — a legal claim on the property — is what makes the home the collateral. Investopedia similarly notes that the property itself serves as collateral for the loan, and that few people pay for a house out of pocket; financing a home purchase is the norm rather than the exception. Put the verified facts together — purchase-size amounts, terms running 15 to 30 years, and the reality that few buyers pay cash — and it follows that for most households the mortgage is the largest loan they will ever take. That sentence is an inference from these facts, not a quotation from any of the sources.

Down payment, principal, and the amortizing payment

The down payment is the amount the buyer pays up front; the principal is the amount actually borrowed, on which interest is calculated. The two are linked: a larger down payment means a smaller loan, and the CFPB notes that a larger down payment typically means a lower interest rate and a likelier approval, because the lender carries less risk. Mortgage terms commonly run 15, 20, or 30 years, and repayment happens through amortization — regular payments that gradually pay off the loan. Because interest is calculated on the full remaining principal, and that principal is largest at the start, early payments go mostly to interest, with only a small slice reducing the balance. On a $216,000 loan at 6.5 percent for 30 years, the first payment splits into roughly $1,170 of interest and $195 of principal, and about 85 percent of year-one payments go to interest. Over the full term, that loan costs about $491,500 in total — roughly $275,500 of it interest, on top of the $216,000 borrowed.

What the monthly payment really covers: PITI, escrow, and PMI

A monthly mortgage payment is not only the loan. Lenders commonly describe it as PITI — principal, interest, taxes, and insurance. The taxes and insurance parts are handled through an , also called an impound account: part of each monthly payment goes into the account, and the lender uses it to pay property taxes and homeowners insurance when they come due. The CFPB describes this as smoothing what would otherwise be large annual bills into a predictable monthly amount. Private mortgage insurance, or PMI, is a separate layer that appears when the down payment is small. The CFPB is explicit about whom it protects: PMI protects the lender, not the borrower, and it is typically required on conventional loans when the down payment is below 20 percent. It adds to the monthly cost, which is one reason larger down payments can be cheaper over time despite the larger upfront amount.

Fixed-rate versus adjustable-rate, and what foreclosure means

Mortgage rates come in two basic designs. A keeps the same interest rate for the entire life of the loan, so the principal-and-interest payment stays the same month after month. An , or ARM, starts with a rate that can change after an initial period, based on market conditions. The CFPB's loan-options explainer describes the trade plainly: a fixed rate gives predictable payments, while an adjustable rate can move up or down over time, which can make future payments harder to forecast. The other side of the agreement is what happens when payments stop. The CFPB explains that foreclosure is the process by which the lender uses the sale of the home to satisfy the unpaid debt, and that it may begin after the borrower falls a few months behind. The honest framing: the right to take the property is not a technicality in the definition — it is the enforcement mechanism that makes the home the collateral, and it is the real consequence of borrowing against the home.

Eli, the EliExplains learning guide

Eli explains

The same idea, in plain words

Explain it like I’m 10

A mortgage is a loan for buying a home, and the home itself is the promise to repay: miss enough payments and the lender can take the house. You pay a down payment up front, borrow the rest as the principal, and repay it month by month over a long term — usually 15, 20, or 30 years. Because the balance is huge and the term is long, the monthly payment mostly covers interest at first, and only gradually starts shrinking the principal; that gradual repayment is called amortization. The payment often covers more than the loan itself: part goes into an escrow account for property taxes and homeowners insurance, and a small down payment can add private mortgage insurance.

Picture it like this

Buying with a mortgage is like buying a car with a partner who actually owns the car with you: you bring part of the price, they cover the rest, and every month you buy out another slice of their share until the car is fully yours. While their share is unpaid, they keep the title as security — and if you stop paying, they can take the car.

Where the picture stops working

The lender is not a friendly co-owner. It charges interest on the unpaid share, so the total you repay is far more than the price of the home. And its security is not a handshake: the home is collateral, and a lender that is not paid can foreclose and sell the property to recover the debt — a real loss for the borrower.

Worked example

Nadia buys a $240,000 condo with a 10 percent down payment of $24,000, so she borrows $216,000 on a 30-year fixed-rate mortgage at 6.5 percent. Her principal-and-interest payment is about $1,365 a month, and because her down payment is under 20 percent she also pays private mortgage insurance on top. Her first payment splits into roughly $1,170 of interest and $195 of principal — about 85 percent of her year-one payments go to interest. Over 30 years she repays about $491,500 in total, roughly $275,500 of it interest. The escrow portion of her payment covers property taxes and homeowners insurance, so those bills arrive monthly rather than as annual surprises.

Key takeaway

A mortgage is a loan for a home with the home as collateral: a down payment plus principal repaid with interest over 15 to 30 years, with taxes, insurance, and possibly PMI folded into the monthly payment. The total repaid can be far more than the price of the home, so rate, term, and down payment deserve close attention.

Quick check

3 questions here, of 5 in this lesson’s practice set. Answers stay hidden until you check.

Question 1 of 3foundational

In a mortgage, what is the principal?

Choose an answer, then check it.
Question 2 of 3intermediate

How does a fixed-rate mortgage differ from an adjustable-rate mortgage?

Choose an answer, then check it.
Question 3 of 3intermediate

A buyer makes a 5 percent down payment on a conventional mortgage. Which of the following is the typical result?

Choose an answer, then check it.
Practice all 5

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Study tools & related lessonsYou’ll learn to · Common mistakes · Easily confused · Key vocabulary · Related

You’ll learn to

  • Define a mortgage as a loan used to purchase or refinance a home, with the home itself serving as collateral.
  • Name the parts of a mortgage — down payment, principal, interest, term, and monthly payment — and explain how amortization pays down the balance over time.
  • Explain what a monthly mortgage payment commonly covers, including principal, interest, taxes, and insurance (PITI), and what an escrow account does.
  • Distinguish a fixed-rate mortgage, whose rate stays the same for the life of the loan, from an adjustable-rate mortgage, whose rate can change after an initial period.
  • Explain what private mortgage insurance is and whom it protects, and why it is typically required when the down payment is below 20 percent.
  • Analyze why early mortgage payments go mostly toward interest and why a longer term raises the total interest paid.

Common mistakes

  • Reading the monthly payment as mostly repaying the house.

    In the early years, most of the payment is interest, because interest is calculated on the large remaining principal. Principal repayment grows only as the balance shrinks — that is how amortization works.

  • Assuming private mortgage insurance protects the borrower.

    PMI protects the lender, not the borrower, and the borrower pays for it. It is typically required when the down payment is below 20 percent.

  • Treating the escrow portion of the payment as a lender fee.

    The escrow portion is a pass-through: it accumulates and pays property taxes and homeowners insurance. The lender collects it but does not keep it as profit.

  • Assuming a smaller monthly payment means a cheaper mortgage.

    A longer term shrinks the monthly payment but adds months of interest, so total interest can be far higher. Comparing mortgages means comparing rate, term, down payment, and total cost.

Easily confused

Fixed-rate mortgage vs. Adjustable-rate mortgage

A fixed rate stays the same for the life of the loan, keeping principal-and-interest payments predictable; an ARM's rate can change after an initial period, based on the market.

Down payment vs. Principal

The down payment is paid up front and reduces the amount borrowed; the principal is the amount actually borrowed, on which interest is calculated.

Interest portion of a payment vs. Escrow portion

Interest is the lender's charge for the money and is kept by the lender; the escrow portion is collected monthly and passed through to pay property taxes and homeowners insurance.

Key vocabulary

mortgage
A loan used to purchase or refinance a home, secured by the home itself as collateral.
principal
The amount of money borrowed to buy the home, on which interest is calculated.
down payment
The amount the buyer pays up front, which reduces the amount borrowed.
amortization
The gradual paying off of a loan through regular payments over a set term.
fixed-rate mortgage
A mortgage whose interest rate stays the same for the entire life of the loan.
adjustable-rate mortgage
A mortgage whose interest rate can change after an initial period, based on market conditions.
escrow account
An account the lender uses to pay property taxes and homeowners insurance from monthly payments.
private mortgage insurance
Insurance that protects the lender, typically required when the down payment is below 20 percent.

Sources & references

  1. Mortgage key terms (Consumer Tools: Mortgages) — Consumer Financial Protection Bureau (CFPB)
  2. What is private mortgage insurance? (Ask CFPB, en-122) — Consumer Financial Protection Bureau (CFPB)
  3. What kind of down payment do I need? (Ask CFPB, en-120) — Consumer Financial Protection Bureau (CFPB)
  4. How does foreclosure work? (Ask CFPB, en-287) — Consumer Financial Protection Bureau (CFPB)
  5. What should I do if I'm having problems with my escrow or impound account? (Ask CFPB, en-2082) — Consumer Financial Protection Bureau (CFPB)
  6. Loan options (Owning a Home) — Consumer Financial Protection Bureau (CFPB)
  7. Mortgage: definition, types, and how it works — Corporate Finance Institute (CFI)
  8. Mortgage: definition, how it works, types — Investopedia
  9. Borrow (MyMoney Five) — U.S. Financial Literacy and Education Commission (MyMoney.gov)

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Researched 2026-08-21

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