If you’re studying for your real estate exam, you’ve probably noticed that mortgage concepts come up a lot. One topic that can feel confusing at first is principal vs. interest. The good news is that once you break it down, it’s much easier to understand and remember for test day.
In this guide, you’ll learn what principal and interest are, how they show up in mortgage payments, and the key concepts you need to know to answer exam questions with confidence.
Key takeaways
- Principal Is The Amount Borrowed: Principal refers to the original loan amount a borrower receives from a lender.
- Interest Is the Cost of Borrowing: Interest is the fee charged by the lender for lending money.
- Mortgage Payments Include Both Components: Most monthly mortgage payments contain both principal and interest.
- Amortization Changes Payment Allocation Over Time: Early payments mostly go toward interest, while later payments pay down more principal.
- Principal and Interest Are Common Exam Topics: Understanding these concepts can help you answer real estate exam questions more confidently.
What are principal and interest?
Before diving into calculations and mortgage payments, it’s important to understand the basic definitions.
What is principal?
Principal is the amount of money a borrower receives from a lender when taking out a mortgage.
For example:
- Home purchase price: $300,000
- Down payment: $60,000
- Mortgage loan amount: $240,000
In this example, the mortgage principal is $240,000.
As the borrower makes payments, the principal balance gradually decreases.
What is interest?
Interest is the cost of borrowing money.
When a lender provides a mortgage, they charge interest as compensation for the risk of lending funds.
For example:
- Loan amount: $240,000
- Interest rate: 6%
The borrower pays interest over the life of the loan in addition to repaying the principal.
Practice question
A buyer purchases a home for $350,000 and makes a $50,000 down payment. What is the principal amount of the mortgage?
A. $50,000
B. $300,000
C. $350,000
D. $400,000
Answer: B. $300,000
Related Reading: What is a mortgage? Definitions and study questions to help you prepare for the exam
Types of mortgage loans: A complete guide for real estate agents
How do principal and interest payments work?
Most mortgages use monthly payments that include both principal and interest.
When borrowers make their payment:
- A portion goes toward interest.
- A portion goes toward reducing principal.
The lender calculates interest based on the remaining outstanding principal balance.
Because the balance is highest at the beginning of the loan, the interest portion is also highest at the beginning.
This process is called amortization.
Why early payments contain more interest
Imagine a borrower takes out a $300,000 mortgage.
During the first few years:
- The loan balance is still close to $300,000.
- Interest charges are relatively high.
- Less of each payment reduces principal.
Later in the loan:
- The balance becomes much smaller.
- Interest charges decrease.
- More of each payment goes toward principal.
This shift happens automatically through the amortization process.
Practice question
True or False:
During the first few years of a typical fixed-rate mortgage, most of the monthly payment goes toward principal.
Answer: False. Most of the payment goes toward interest early in the loan term.
How does an amortization schedule show principal vs. interest over time?
An amortization schedule is one of the most important mortgage tools you’ll encounter.
It shows:
- Each payment date
- Payment amount
- Interest paid
- Principal paid
- Remaining loan balance
As the loan progresses, the schedule clearly shows the principal portion increasing and the interest portion decreasing.
For students preparing for the exam, understanding amortization schedules can help with math questions and mortgage-related concepts.
Example of payment progression
Imagine a $250,000 mortgage with a fixed interest rate.
Early payments may look something like:
| Payment Number | Interest Paid | Principal Paid |
|---|---|---|
| 1 | $1,250 | $250 |
| 12 | $1,235 | $265 |
| 120 | $950 | $550 |
| 300 | $200 | $1,300 |
The total payment may stay the same, but the allocation changes over time.
Learn more about amortization
If you’d like a visual walkthrough of amortization schedules and how mortgage balances change over time, check out this helpful Colibri Real Estate YouTube video:
Calculating principal and interest: Formulas and examples
Real estate licensing exams often include basic mortgage calculations.
Let’s look at a few examples.
How to calculate your current principal balance
The basic formula is:
Original loan amount − total principal paid = outstanding principal balance
Example:
- Original mortgage: $250,000
- Principal paid so far: $30,000
Current principal balance:
$250,000 − $30,000 = $220,000
How to calculate monthly interest payments
The formula is:
(Outstanding principal × annual interest rate) ÷ 12
Example:
- Outstanding principal: $240,000
- Interest rate: 6%
Calculation:
$240,000 × 0.06 = $14,400
$14,400 ÷ 12 = $1,200
Monthly interest payment = $1,200
Practice question
A borrower has an outstanding principal balance of $200,000 and an annual interest rate of 6%.
Approximately how much interest accrues each month?
A. $500
B. $750
C. $1,000
D. $1,500
Answer: C. $1,000
Strengthen your real estate math skills
Mortgage calculations, interest rates, and amortization schedules are common exam topics. To get more practice with real estate math concepts, explore Colibri Real Estate’s free YouTube playlist:
Want to grow your real estate knowledge beyond the exam?
Understanding mortgage concepts is important for passing your licensing exam, but successful agents also build strong professional networks that help them generate referrals and support clients throughout the transaction process.
Watch this free webinar replay to learn how agents can activate vendor partnerships, protect transactions, and create additional referral opportunities:
What else is included in monthly mortgage payments?
Many first-time homebuyers assume a mortgage payment only includes principal and interest.
In reality, lenders often collect several additional expenses through a single monthly payment.
A common acronym you’ll see is PITI:
- Principal
- Interest
- Taxes
- Insurance
Additional costs may include:
- Private Mortgage Insurance (PMI): A type of insurance that protects the lender if the borrower defaults on the loan, typically required when the down payment is less than 20%.
- FHA Mortgage Insurance Premiums (MIP): Insurance required on FHA loans that protects the lender, usually paid both upfront and as part of the monthly mortgage payment.
- Homeowners association (HOA) fees: Monthly or annual fees paid by homeowners in certain communities to cover maintenance, amenities, and shared services.
- Escrow account contributions: Monthly payments collected by the lender to cover future property taxes and homeowners insurance, which the lender pays on the homeowner’s behalf when due.
What factors affect principal and interest payments?
Several factors influence how much borrowers pay each month.
Important factors include:
- Loan amount: The total amount of money borrowed from the lender.
- Down payment size: The upfront amount the buyer pays, which reduces the loan amount.
- Interest rate: The percentage charged by the lender for borrowing the money.
- APR: The annual percentage rate, which includes the interest rate plus additional loan costs, giving a more complete picture of the loan’s total cost.
- Loan term: The length of time the borrower has to repay the loan, such as 15 or 30 years.
- Credit score: A number that reflects a borrower’s creditworthiness and can affect loan approval and interest rates.
- Debt-to-income ratio (DTI): A comparison of a borrower’s monthly debt payments to their income, used by lenders to assess risk.
- Market conditions: Economic factors like inflation and housing demand that can influence interest rates and loan availability.
For example:
- A larger down payment generally reduces principal.
- A lower interest rate reduces interest costs.
- A shorter loan term often increases monthly payments but reduces total interest paid.
How do interest rates impact principal reduction?
Interest rates play a major role in how quickly borrowers build equity.
Generally:
- Higher interest rates mean more money goes toward interest.
- Lower interest rates allow more money to reduce principal.
- Lower rates often result in faster equity growth.
This is one reason buyers often compare multiple lenders before choosing a mortgage.
Practice question
Which statement is generally true?
A. Higher interest rates help borrowers build equity faster.
B. Lower interest rates often allow more principal reduction.
C. Interest rates do not affect principal reduction.
D. Principal and interest are unrelated.
Answer: B. Lower interest rates often allow more principal reduction.
Should I make extra principal payments on my mortgage?
Many homeowners choose to make additional principal payments.
Benefits can include:
- Faster loan payoff
- Reduced total interest paid
- Increased home equity
Common strategies include:
- Monthly extra principal payments
- Annual lump-sum payments
- Biweekly payment schedules
However, borrowers should also consider:
- Emergency savings goals
- Higher-interest debt
- Investment opportunities
- Potential prepayment penalties
Refinancing to reduce interest or adjust terms
Refinancing may help borrowers:
- Obtain lower interest rates
- Change loan terms
- Switch between ARM and fixed-rate loans
- Build equity faster with shorter terms
Debt consolidation and its impact on principal
Some homeowners use home equity to consolidate debt.
Potential advantages include:
- Lower interest rates
- Simplified payments
Potential risks include:
- Increasing mortgage debt
- Extending repayment periods
Frequently asked questions about principal and interest
What’s the difference between principal and interest in simple terms?
Principal is the amount borrowed.
Interest is the fee charged for borrowing the money.
Can you give me an example of principal and interest in action?
Suppose a borrower takes out a $200,000 mortgage.
A monthly payment might include:
- $900 toward interest
- $300 toward principal
As time passes, more of the payment shifts toward principal.
Will my principal or interest ever change during my loan?
The principal balance changes whenever payments reduce the loan balance.
Interest rates can change on adjustable-rate mortgages or after refinancing.
How can I use this knowledge to better manage my money?
Understanding principal and interest helps borrowers:
- Compare loan options
- Evaluate refinancing opportunities
- Pay loans off faster
- Build equity more efficiently
What is principal vs. interest in a nutshell?
Principal is what you borrow.
Interest is what you pay to borrow it.
Take the next step with Colibri Real Estate exam prep
Mortgages are one of the most important topics you’ll encounter as a real estate professional. Understanding how mortgages work, the different loan options available, and the key terms involved can help you better support clients and build confidence in your real estate knowledge.
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