Definition
An interest rate is the percentage used to calculate the cost of borrowing the mortgage balance.
If you are comparing mortgage options, treat interest rate as one piece of the total cost and risk picture, not a standalone detail.
Why It Matters
It matters because even small rate changes can meaningfully change monthly payment and total interest.
Simple Example
A 0.50 percentage point rate difference can change payment by hundreds of dollars on a large loan.
How to Use This Term
When you see interest rate on a loan estimate, calculator result, or lender conversation, connect it to three practical questions: how it affects monthly payment, how it affects cash needed now, and how it affects flexibility later.