Mortgage Basics

A mortgage is a loan used to purchase real estate, in which the property itself serves as collateral for the lender. If the borrower stops paying under the agreed terms, the lender can initiate a legal process — known as foreclosure — that may result in the loss of the property. For this reason, understanding the basic concepts before taking on a mortgage is essential.

The main elements of a mortgage

A typical mortgage combines several elements that are worth distinguishing:

• Principal. The total amount borrowed.
• Interest. The cost of the borrowed money, expressed as a percentage.
• Term. The period over which the loan is amortized. In the United States, common terms are 15, 20, or 30 years.
• Monthly payment. The periodic payment, which typically includes principal, interest, and, in many cases, taxes and insurance through an escrow account.

The combination of principal, interest, and term determines how payments are distributed over time. In the early years of a long-term mortgage, a significant portion of the monthly payment goes toward interest.

Fixed rate versus adjustable rate

There are two broad families of mortgages according to how the interest rate behaves:

Fixed-rate mortgage. The rate is agreed at the outset and stays constant for the full life of the loan. The monthly payment is predictable, which makes financial planning easier. Its main characteristic is stability.

Adjustable-rate mortgage (ARM). The rate can adjust periodically after an initial fixed period. Terms vary widely and typically specify how often the rate adjusts and what reference index is used. The monthly payment can go up or down according to movements in the index.

Neither alternative is inherently better than the other: each structure involves a different trade-off between predictability and flexibility, and its suitability depends on each consumer's situation.

A mortgage is typically the largest financial commitment a family will take on.

What a lender evaluates

Before approving a mortgage, a lender reviews several factors that help estimate the risk of the loan. Although each institution has its own criteria, the usual elements include:

• Credit history and report. Prior behavior with other financial obligations.
• Verifiable income. Documentation of stable income and its source.
• Debt-to-income ratio. The proportion between existing monthly obligations and income.
• Savings and assets. Resources available for the down payment and for reserves after the purchase.
• Employment situation. Continuity and type of employment.
• Property appraisal. The market value that an independent appraiser assigns to the property.

Additional costs

Beyond principal and interest, a mortgage involves costs that are often underestimated: closing costs, insurance, property taxes, and, in some cases, private mortgage insurance when the down payment is below a certain threshold. These costs should be considered within the full analysis of the financial commitment, not just the monthly payment.

Before you apply

Understanding your own financial situation — stable income, expenses, current debts, credit history, and available savings — is an important preliminary step before starting the mortgage process. Many consumers find it helpful to consult a qualified professional, review their credit report, and understand the various programs available in the market before committing to a long-term mortgage.

A mortgage is typically the largest financial commitment a family will take on. Taking the time necessary to understand how it works avoids surprises and contributes to an informed decision.

This article is for educational purposes and is reviewed periodically.