Can I make extra payments on a 30-year to mimic a 15-year?

Yes — and this is often the best of both worlds. A $300,000 30-year at 7% has a base payment of about $1,996. Paying an extra $700/month (to roughly match the 15-year payment) pays it off in about 17 years and saves over $200,000 in interest. You keep the flexibility to drop back to the $1,996 minimum if your income changes.

Are 15-year rates really lower?

Historically yes — typically 0.5-0.75% lower than 30-year rates. Lenders price in less interest-rate risk for a shorter loan. The rate gap varies with the yield curve; during inverted-curve periods, the spread can shrink or even flip briefly.

What if I can't afford the 15-year payment?

Take the 30-year. Being house-poor forces you to make bad financial choices in every other area — skipped retirement contributions, no emergency fund, credit card debt. The 30-year's flexibility is worth real money, even if the headline interest cost is higher.

Does paying off early hurt your credit score?

Your mortgage is one of the longest-running tradelines on your credit report. Paying it off closes that account, which can cause a small, temporary dip in your score (typically 10-30 points). It rebounds quickly and the savings far outweigh the impact for most people.

What about a 20-year mortgage?

Available but less common — rates are usually between 15 and 30 year rates, payments are a middle ground. Often a better choice than a 30 for borrowers who want to cut interest meaningfully but can't swing the 15-year payment. Ask your lender to quote you all three for an apples-to-apples view.

15-Year vs 30-Year Mortgage: Which Actually Costs Less?

On paper, a 15-year mortgage is a screaming deal: you'll save roughly $200,000 in intereston a typical $300,000 loan and own your home outright twice as fast. In practice, the higher monthly payment is a real constraint that costs many borrowers more than they save. Here's how to think about the tradeoff.

The headline numbers

A $300,000 loan at prevailing rates:

30-year at 7%: payment ~$1,996/month, total interest paid over 30 years ≈ $418,000
15-year at 6.25%: payment ~$2,572/month, total interest ≈ $163,000

That's $255,000 of savings and 15 fewer years of payments, but you're paying $576 more per month. Over the first 15 years, that extra is $103,680. You're essentially trading $103k of early cash flow for $255k of long-term savings — a great trade if you can afford it and still invest the difference.

Run these numbers with your actual rate and loan amount in the mortgage calculator.

When the 15-year wins

You've maxed out tax-advantaged accounts. If you're already contributing the max to 401(k), IRA, HSA, and still have extra cash, the 15-year's forced savings (really, forced debt paydown) is hard to beat.
You're in your peak earning years with stable income. A high-income surgeon or senior engineer with 10+ years of salary stability can absorb the higher payment without straining other goals.
You want to be mortgage-free by retirement. A 15-year taken at 50 lets you retire at 65 debt-free. A 30-year at 50 means payments through age 80.
You value simplicity.Some people genuinely dislike having debt and sleep better without it. That's a valid preference, even if math would favor investing the difference.

When the 30-year wins

You're not maxing retirement accounts. The long-term, tax-advantaged return from a 401(k) match plus index-fund growth (7%+ historical real return) usually beats the interest savings from accelerated mortgage payoff.
Your income is variable or early-career. Freelancers, commission workers, and people who might voluntarily change jobs benefit from the lower mandatory payment. You can always pay extra; you can't always pay less.
You have high-interest debt elsewhere. Paying off 19% credit card debt is worth far more than shortening a 7% mortgage.
You haven't built an emergency fund. Six months of expenses in a high-yield savings account is a prerequisite for taking on any aggressive debt-payoff strategy.

The best-of-both-worlds option

Take the 30-year and pay extra principal each month. On a $300k 30-year at 7%, adding $576/month (matching the 15-year payment) pays the loan off in about 18 years and saves roughly $190,000 in interest. You retain the flexibility to drop back to the base payment if you lose your job, have a medical issue, or just want to take a sabbatical.

The only downside vs. a true 15-year: you'll pay a slightly higher interest rate (no 15-year discount) and you have to have the discipline to actually make the extra payment. Automate it and this is usually the right answer.

What about a 30-year with the extra invested instead?

This is the classic math-vs-behavior debate. If you take the 30-year and invest the $576/month difference at 7% for 15 years, you'd have roughly $183,000 in a brokerage account. Compare that to the $255k of interest savings from the 15-year. On surface the 15-year wins — but the brokerage money stays yours, liquid, and can compound for 15 more years after that.

The variable most people miss: few borrowers actually invest the difference. They spend it. The 15-year's forced structure has real behavioral value — if you're honest with yourself about whether you'd invest the gap.

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