APR

Annual Percentage Rate

Definition

The yearly cost of credit including interest and most fees, expressed as a percentage. APR is higher than the note rate when you pay origination fees or points. It lets you compare offers with different fee structures.

Example

If you borrow $200,000 at 5% interest but pay $4,000 in upfront fees, your APR will be closer to 5.15% because you're effectively borrowing less money but paying the same interest.

Common Trap

"Many assume APR dictates their exact monthly payment. It doesn't. Your monthly payment is based strictly on the interest rate, while APR just gives you the true, blended cost over the life of the loan."

Why It Matters

When comparing two lenders, one might offer a lower interest rate but pile on massive origination fees. APR levels the playing field so you can see which loan is actually cheaper overall.

Interest rate

The note rate on the loan

Definition

The contractual rate used to compute each month's interest. Unlike APR, it excludes fees. A lower note rate with high fees can be more expensive than a slightly higher rate with no fees.

Example

A 6.5% interest rate on a $300,000 mortgage means your first month's interest charge will be exactly $1,625 ($300,000 x 6.5% / 12).

Common Trap

"People often confuse interest rate and APR, treating them as interchangeable terms. The interest rate determines your payment; the APR represents total borrowing cost."

Why It Matters

This is the single most important number for calculating your actual cash flow and month-to-month budget. If your budget is tight, prioritizing a lower interest rate might be necessary even if the APR is slightly higher.

LTV

Loan-to-value ratio

Definition

Loan amount divided by property value. An LTV above 80% often triggers mortgage insurance (PMI, LMI, or equivalent) and may mean a higher rate.

Example

If you buy a $500,000 home with a $100,000 down payment, your loan is $400,000. Your LTV is 80% ($400,000 / $500,000).

Common Trap

"Buyers sometimes think LTV is based purely on the purchase price. In reality, it's based on the *lesser* of the purchase price or the appraised value. If the appraisal comes in low, your LTV shoots up."

Why It Matters

Lenders use LTV to measure their risk. Crossing the 80% threshold usually means you'll pay a monthly penalty (mortgage insurance) to protect the lender in case you default.

DTI

Debt-to-income ratio

Definition

Monthly debt payments divided by gross monthly income. US underwriting commonly uses a 28% front-end (housing) and 36% back-end (all debts) guideline; other countries use different caps or income multiples.

Example

If you make $10,000 a month gross, and your future mortgage plus student loans and car payments total $4,000, your DTI is 40%.

Common Trap

"A common trap is calculating DTI using your take-home (net) pay. Lenders almost always use your gross (pre-tax) income, which can make the ratio look deceptively optimistic compared to your actual cash flow."

Why It Matters

It's the ultimate gatekeeper for getting approved. Even with perfect credit and a huge down payment, a DTI that is too high will stop your application dead in its tracks.

Amortization

Paying down principal over time

Definition

With a fully amortizing loan, each payment covers that month's interest and a growing slice of principal. Early payments are interest-heavy; later payments are principal-heavy. An amortization schedule shows the split every month.

Example

In year one of a 30-year mortgage, 75% of your payment might go straight to interest. By year 28, 90% of your payment goes toward paying down the principal.

Common Trap

"People are often shocked after 5 years of paying a mortgage to find their loan balance has barely moved. This isn't a scam or a mistake; it's just the math of amortization heavily front-loading the interest."

Why It Matters

Understanding this curve is the secret to wealth building. Making even small extra payments early in the loan knocks out principal before it has decades to accrue interest, saving you tens of thousands of dollars.

Principal

The amount you actually borrow

Definition

The loan balance, not including interest. Extra payments applied to principal shorten the term and cut total interest because future interest is charged on a smaller balance.

Example

If you borrow $250,000 to buy a house, that $250,000 is your principal. When you send an extra $500 payment 'to principal', your new balance becomes $249,500 immediately.

Common Trap

"Many believe their regular monthly payment is split 50/50 between principal and interest. In reality, the split changes every single month, starting heavily skewed toward interest."

Why It Matters

The principal is the root cause of your interest charges. Kill the principal faster, and you starve the loan of its ability to charge you interest.

Escrow / impound

Tax and insurance collected with the payment

Definition

In some markets the lender collects property tax and home insurance monthly and pays the bills when due. That is why a 'monthly payment' is often PITI, not just principal and interest.

Example

If your property taxes are $6,000 a year and insurance is $1,200 a year, the lender adds $600 to your monthly mortgage payment, holding it in an escrow account until those bills are due.

Common Trap

"Homeowners often get angry at the lender when their 'mortgage payment' goes up. Usually, the actual mortgage is fixed; it's the property taxes or insurance in the escrow account that increased."

Why It Matters

It prevents you from being hit with massive, unexpected tax or insurance bills at the end of the year, but it also means you lose the ability to earn interest on that cash throughout the year.

PITI

Principal, interest, taxes, insurance

Definition

The full housing payment used in affordability tests. HOA dues and mortgage insurance are usually added on top.

Example

Principal and Interest: $1,500. Taxes: $400. Insurance: $100. Your total PITI is $2,000.

Common Trap

"First-time buyers often look at a mortgage calculator showing just 'Principal + Interest' and assume that's their final housing cost, severely underestimating their true monthly burden."

Why It Matters

Lenders calculate your Debt-to-Income (DTI) ratio using the full PITI, not just the loan payment. If you ignore taxes and insurance, you'll be rejected for a loan you thought you could afford.

PMI / LMI

Mortgage insurance

Definition

Insurance that protects the lender, not you, when LTV is high. In the US, PMI on a conventional loan typically drops at 80% LTV (78% automatically). Australia's LMI is usually a one-time premium.

Example

Putting down 5% on a $400,000 home might cost you an extra $150 every month in PMI until your loan balance drops to $320,000.

Common Trap

"Borrowers frequently assume PMI protects *them* if they lose their job and can't pay. It doesn't. It strictly protects the bank if they have to foreclose on you at a loss."

Why It Matters

It's essentially 'dead money' leaving your pocket every month. However, it's also a powerful tool that allows people to buy homes years earlier than if they had to save a full 20% down payment.

Discount points

Prepaid interest to buy down the rate

Definition

One point costs 1% of the loan amount. Whether points are worth it depends on how long you keep the loan — the break-even is cost divided by monthly savings.

Example

On a $300,000 loan, buying 1 point costs $3,000 upfront at closing, but it might lower your interest rate from 7.0% to 6.75%, saving you $50 a month.

Common Trap

"People think a 'point' is always a full percentage point off the interest rate. It's not. 1 point costs 1% of the loan amount, but typically only lowers the rate by about 0.25%."

Why It Matters

If you plan to stay in the home for 10+ years, buying points can save you massive amounts of money. If you plan to move or refinance in 3 years, you'll lose money on the upfront cost.

Fixed vs variable

How the rate can change

Definition

A fixed rate stays the same for a set period (or the whole term). A variable / tracker / ARM rate can move with a benchmark. Compare the initial rate, the margin, caps, and the stress rate used for affordability.

Example

A 5/1 ARM stays fixed at 5.5% for five years, then adjusts annually based on the market. A 30-year fixed stays at 6.0% for all three decades.

Common Trap

"Borrowers often think variable rates are a scam designed to cause foreclosures. In reality, outside the US, variable or short-term fixed rates are the global standard, and they can be vastly cheaper in falling-rate environments."

Why It Matters

It dictates who takes the risk of the economy changing. With a fixed rate, the bank takes the risk. With a variable rate, you take the risk (but are rewarded with a lower initial rate).

Interest-only

Pay interest, not principal

Definition

Common in the UK, Denmark, and Switzerland. The payment is lower, but the balance does not fall and you still owe the principal at the end of the IO period unless you repay it from other assets.

Example

On a $500,000 loan at 6%, an interest-only payment is exactly $2,500 every month. After 5 years of perfect payments, you still owe exactly $500,000.

Common Trap

"People assume interest-only loans are inherently dangerous. While risky if unmanaged, savvy investors use them to maximize monthly cash flow while investing the difference elsewhere."

Why It Matters

It massively reduces your monthly payment, freeing up capital for investments or surviving tight financial periods, but it completely halts your equity growth from amortization.

Negative equity

Owing more than the home is worth

Definition

If prices fall, LTV can exceed 100%. That makes refinancing and selling harder. A larger down payment and conservative price assumptions reduce the risk.

Example

You buy a home for $400,000 with a $20,000 down payment. The market drops, and the home is now worth $350,000, but you still owe $375,000. You are $25,000 in negative equity.

Common Trap

"Homeowners think negative equity means they have to immediately pay the bank the difference. You don't. As long as you keep making the monthly payment, you can simply ride it out until the market recovers."

Why It Matters

It essentially traps you in the house. If you are forced to move (e.g., for a job), you would have to literally write a massive check to the bank just to sell your own house.

Serviceability

Can you still pay if rates rise?

Definition

Australia, Canada, Hong Kong and others qualify you at a stressed rate (advertised rate plus a buffer, or a floor). The payment you are approved for is higher than today's payment.

Example

In Canada, you might apply for a 5% mortgage, but the bank will test your finances as if the rate were 7% to ensure you could survive a sudden rate hike.

Common Trap

"Applicants get frustrated thinking the bank is trying to scam them by using a higher rate. It's actually a government-mandated safety net to prevent massive foreclosure waves if inflation spikes."

Why It Matters

This is the invisible wall that limits your borrowing power in heavily regulated countries. Your actual budget might feel roomy, but the stress test determines your legal maximum loan.

Opportunity cost

What the down payment could have earned

Definition

Rent-vs-buy math has to count the return you give up by locking cash in a house, not just the mortgage rate. That is why the renter's invested down payment appears in the comparison.

Example

Putting $100,000 into a house down payment means you miss out on making $7,000 a year if you had invested that money in an index fund returning 7%.

Common Trap

"The 'renting is throwing money away' argument ignores opportunity cost. While rent doesn't build equity, the renter's heavily invested stock portfolio often outpaces the homeowner's housing equity."

Why It Matters

It completely changes the math on whether it's better to rent or buy. When stock markets perform well, renting and investing the difference often beats buying a home.