Most first-time buyers apply to one or two lenders and accept the first reasonable offer they get. This is a significant financial mistake. The difference between the best and average mortgage offer on a $350,000 loan can easily amount to $30,000-$60,000 in total interest paid over 30 years. This guide explains the loan types, shows you what the real cost of interest looks like over time, explains discount points, and gives you a side-by-side comparison framework you can use when evaluating actual offers.
Fixed-rate vs. adjustable-rate mortgages (ARM)
The first decision is whether to get a fixed-rate loan or an adjustable-rate mortgage.
| Factor | Fixed-Rate | Adjustable-Rate (ARM) |
|---|---|---|
| Rate behavior | Locked for the life of the loan; never changes | Fixed for initial period (5, 7, or 10 years), then adjusts annually |
| Initial rate | Higher than ARM initial rate | Usually 0.5-1.5% lower than fixed at the start |
| Payment certainty | Payment never changes (excluding tax/insurance changes) | Payment can increase significantly after fixed period ends |
| Best for | Buyers who plan to stay 7+ years and want budget certainty | Buyers who plan to sell or refinance before the fixed period ends |
| Risk level | Low; predictable | Higher; depends on market rates when adjustment occurs |
For most first-time buyers who plan to stay in the home for the long term, a fixed-rate loan is the right choice. The certainty has real value. ARMs make sense if you have a clear exit plan within the fixed period and the initial rate savings are meaningful.
15-year vs. 30-year mortgage
The loan term is one of the most impactful decisions you'll make. Here is what the numbers actually look like on a $300,000 loan at representative rates:
| Scenario | Rate | Monthly Payment | Total Interest Paid |
|---|---|---|---|
| 30-year fixed | 6.75% | $1,946 | $400,560 |
| 15-year fixed | 6.10% | $2,547 | $158,460 |
| Savings with 15-year | $242,100 | ||
The 15-year loan saves $242,100 in total interest but requires $601 more per month. For many first-time buyers, the 30-year loan is the practical choice because it keeps monthly payments manageable and maintains cash flow flexibility. The key insight: if you take a 30-year loan but make extra principal payments consistently, you get much of the benefit without the obligation of the higher payment.
How to compare offers side by side
When you receive Loan Estimates from multiple lenders (you should get at least 3-4), the key figures to compare are:
Mortgage Comparison Worksheet
Compare up to 3 lenders
APR vs. interest rate: The interest rate is the cost of borrowing the principal. The APR (annual percentage rate) includes the interest rate plus fees, giving you a more accurate picture of the true annual cost. When comparing lenders, use APR to compare overall cost, not just the headline rate. A lender offering 6.5% with $4,000 in fees may actually cost more over time than one offering 6.75% with $800 in fees.
Discount points explained
Discount points are prepaid interest you pay at closing to reduce your mortgage rate. One point equals 1% of the loan amount and typically reduces your rate by 0.25% (though this varies by lender and market conditions).
On a $350,000 loan, one point costs $3,500 and might reduce your rate from 6.75% to 6.5%. At 6.5%, your monthly payment drops by about $55. To break even on the $3,500 you paid for the point, you'd need to stay in the loan for approximately 64 months (about 5.3 years). If you sell or refinance before then, buying the point cost you money.
When buying points makes sense: You plan to keep the loan for at least 7-10 years, rates are relatively high and you expect to hold through multiple market cycles, and you have cash available that isn't needed for the down payment or emergency fund.
When to skip points: You might sell or refinance within 5-7 years, you're stretching your cash reserves to close, or the breakeven period is longer than your expected ownership horizon.
The real cost of interest: what buyers miss
Most buyers focus on the monthly payment and the interest rate. What they miss is the amortization structure: in the early years of a 30-year mortgage, the vast majority of each payment goes toward interest, not principal.
On a $350,000 loan at 6.75%:
- Month 1: $1,969 goes to interest, $306 goes to principal
- Year 5: Still $1,845/month to interest, $430 to principal
- Year 15: $1,552/month to interest, $724 to principal
- Year 25: $945/month to interest, $1,330 to principal
This is why the rate matters so much, and why even small rate differences compound into large dollar amounts over time. A 0.5% rate reduction on a $350,000 loan saves approximately $36,000 in total interest over 30 years.
Questions to ask every lender
- What is the rate and APR? Get both numbers, on the same loan type and term, on the same day (rates change daily).
- What are your origination and underwriting fees? These are Section A on the Loan Estimate and are entirely negotiable.
- Is this rate with or without points? Always clarify so you're comparing apples to apples.
- How long is the rate lock? Standard is 30-45 days. If you need longer, ask for it and understand any cost.
- What is the estimated time to close? If your timeline is tight, a lender's processing speed matters as much as the rate.
- What could cause this rate to change before closing? Understand what events (job change, large purchase, credit inquiry) would trigger re-pricing.
- Do you sell loans to other servicers? Your lender may originate your loan and then sell it to another company, changing who you send payments to.
- What is your process for customer issues after closing? If your escrow or payment ever gets confused, you want a lender with a reachable customer service team.
Key takeaway: Submit applications to 3-4 lenders within the same 14-45 day window. Multiple hard credit inquiries for a mortgage within that window are typically treated as a single inquiry by scoring models, so shopping aggressively costs you almost nothing in credit score terms and can save you thousands in interest.
Once you understand your mortgage options, the next step is understanding all the upfront costs. Read our guide to closing costs explained for a full itemized breakdown. And if you're still calculating what you can actually afford, start with our guide on how much house you can afford.