Two numbers answer different questions
The interest rate is used to calculate interest on the outstanding mortgage balance. The annual percentage rate, or APR, incorporates the interest rate and certain borrowing charges into a broader annualized measure. Neither number, on its own, describes the complete monthly cost of owning a home. Property taxes, insurance, association dues, repairs and maintenance still need their own place in your budget.
Match the loan before comparing the price
Put offers side by side with the same loan amount, loan term, occupancy, property and rate-lock period. Ask for the same approach to discount points and lender credits. A quote for a smaller loan or a larger down payment is not an equivalent offer. Capture the date and time as well: comparing yesterday's unlocked quote with today's locked offer can mistake a market change for a lender price difference.
Use dollars alongside percentages
Imagine two hypothetical fixed-rate offers with different upfront costs. The one with a lower interest rate may require several thousand dollars more at closing. Calculate the monthly difference, then compare cumulative costs at the time you realistically expect to sell, refinance or pay off the loan. Keeping an emergency reserve can matter more than a small payment reduction. Ask for a version with fewer points if the advertised offer uses more cash than you want to commit.
Know where APR comparisons become difficult
An adjustable-rate loan introduces assumptions about future rates, so its APR is not a worst-case payment forecast. A HELOC's APR also is not calculated like a closed-end mortgage APR and may exclude costs included in a mortgage comparison. For those products, review fees, adjustment rules, repayment schedules and maximum payment exposure directly. Use the Loan Estimate for an eligible closed-end mortgage and the lender's HELOC disclosures for a credit line; ask about unexplained differences before selecting an offer.
Make a one-page comparison
For each offer, record the rate, APR, points, lender credit, total loan costs, monthly principal and interest, mortgage insurance and cash to close. Add a note identifying whether the quote is locked. Highlight any row that differs because of a changed assumption before deciding which lender is less expensive. When a charge is unclear, ask for its purpose and whether it changes across the alternatives. Keep the written response with the comparison so a later revision can be checked against the original offer.
Common questions
Is the lowest APR always the best mortgage?
It is a useful comparison measure, but your holding period, cash needs, loan features and payment risk can change which option fits.
Why is APR often higher than the interest rate?
APR generally reflects certain borrowing costs in addition to interest. Ask the lender which charges are included in the calculation.
Sources & further reading
General educational information. Our editorial standards, ownership and AI-assistance disclosure.