Loan Term Comparison

30-Year vs 15-Year Mortgage: Which Is Better?

George Smith — Founder, Klickify Agency

You are buying a $420,000 home. The lender gives you two options: a 30-year mortgage at 6.8% or a 15-year mortgage at 6.2%. The 15-year rate is lower — a full half point. You want to save on interest. But the monthly payment on the 15-year is much higher. You are not sure if you can afford it. You search for a comparison online, but many sites push you to "talk to a lender" before they will even show you the two options side by side.

Most online mortgage calculators default to the 30-year term, and over the life of a loan a lender generally collects more interest on a 30-year than on a 15-year because you pay for twice as long. Many calculators do not surface the 15-year math unless you manually change the term, and even then they tend to highlight the higher monthly payment without putting the interest savings right next to it. That framing quietly nudges you toward the longer term.

The decision between a 30-year and a 15-year mortgage is not just about monthly cash flow. It is about your stage of life, your other financial goals, and your tolerance for risk. I am going to show you the real numbers for an example $420,000 home with 20% down. Then you can decide which path makes sense for you.

The Real Numbers: 30-Year vs 15-Year on a $420,000 Home

Let me lay out the exact math. Home price: $420,000. Down payment: 20% ($84,000). Loan amount: $336,000. For a 30-year fixed at 6.8% — close to the average tracked in Freddie Mac's Primary Mortgage Market Survey — the monthly principal and interest payment is $2,191. Total interest paid over 30 years: $453,000. Total paid (principal + interest): $789,000. For a 15-year fixed at 6.2%, the monthly principal and interest payment is $2,869. That is $678 more per month. Total interest paid over 15 years: $180,000. Total paid: $516,000.

The difference in total interest is $273,000. That is real money. That is a year of salary for many people. If you can afford the extra $678 per month, the 15-year saves you that $273,000 in interest over the life of the loan. Still huge. But here is the catch. That $678 per month invested in the stock market at an average 7% return over 15 years would grow to about $210,000. So the opportunity cost is real. If you are a disciplined investor, you might come out ahead by taking the 30-year and investing the difference.

But most people do not invest the difference. They spend it. The 30-year gives you flexibility. If you lose your job or have an emergency, you can drop down to the lower $2,191 payment. With the 15-year, you are locked into $2,869. That extra $678 per month is a commitment. For a dual-income household with stable jobs, the 15-year might be worth it. For a single buyer or someone with variable income, the 30-year is safer.

Let me add one more scenario. What if you take the 30-year but make extra payments equal to the 15-year payment? You would pay $2,869 per month on the 30-year loan. That extra $678 goes straight to principal. You would pay off the 30-year loan in about 16 years — slightly longer than the 15-year term. Total interest paid would be roughly $217,000, which is about $37,000 more than the 15-year loan at 6.2%. The difference is because the 15-year has a lower interest rate. So if you can qualify for the lower rate, the 15-year is mathematically better. But many lenders offer the same rate for both terms, in which case the math flips.

Step-by-Step: Compare 30-Year and 15-Year Using the Calculator

Here is how to run the numbers for your specific situation without giving up your email.

1. Open the mortgage calculator and switch on Scenario Comparison

Scenario Comparison is built into the main mortgage calculator. It gives you two scenarios, A and B, each with its own home price, down payment, rate, and term.

2. Enter your home price and down payment

Use the same numbers for both scenarios. For example, $420,000 home with $84,000 down.

3. Enter the interest rate for each term

Use a rate quote from your own lender. In this example we use 6.8% for the 30-year. The 15-year rate is often slightly lower, typically 0.5% to 0.75% less, so this example uses 6.2%.

4. Read the side-by-side results

For each scenario the calculator shows the loan amount, monthly payment, total interest, and total cost, so you can read the monthly and lifetime difference yourself.

5. Look at the total interest difference

On a $336,000 loan, the difference is about $273,000. That is the cost of the 30-year term. Ask yourself: is the lower monthly payment worth $273,000 over 30 years?

6. Factor in refinance costs if you plan to switch later

The calculator does not estimate refinance closing costs. If you take the 30-year now and plan to refinance into a 15-year later, remember that refinancing typically runs about 2% to 5% of the loan amount, so weigh that cost against the interest you would save. Confirm the actual figures with your lender.

7. Test a middle ground with the extra monthly payment field

Switch to the standard calculator, set up the 30-year loan, and try different amounts in the "extra monthly payment" field to see how much extra you would need to pay to approach a 15-year payoff timeline. It reports the new payoff time, time saved, and interest saved.

8. Compare the two full amortization schedules one at a time

The standard calculator shows one full amortization schedule at a time; it is printable, but there is no side-by-side view of two schedules. Run the 30-year numbers, note the balance at month 60, then switch the term to 15 years and note the balance at the same month to see the equity difference.

The Lead-Gen Problem With Free Mortgage Calculators

Many free mortgage calculators are the front door to a lead-generation funnel. A prominent button invites you to see today's rates; clicking it asks for your zip code, email, and phone number, and that contact information can be shared with or sold to lenders who pay for the referral. The calculator is the bait; your contact details are the product.

Some sites do show rate data, but usually only after you hand over your contact information, which then goes to the lenders listed. Expect follow-up calls and emails. The site is typically paid a referral fee for each lead it passes along.

Others are calculators in name only and are really run by lending networks. On sites like these, the numbers you type can be logged even if you never press submit, and combined with your IP address that data can be tied back to you. If you cannot tell who runs a calculator or how it makes money, it is safest to assume your inputs are being recorded.

Truly Free Mortgage Calculator does not track your inputs. There is no lead form. No "compare rates" button. No lender network. The only way I make money is from display ads on the page. You can run as many comparisons as you want, and your phone will never ring. That is the difference between a tool and a trap.

Compare 30-Year vs 15-Year Free

No account. No email. Runs in your browser.

Frequently Asked Questions

Is a 15-year mortgage always better if you can afford the payment?

Not always. The 15-year locks you into a higher payment. If you lose your job or have a medical emergency, you cannot easily reduce that payment. The 30-year gives you flexibility. You can always pay extra on the 30-year to mimic a 15-year payoff. But you cannot pay less on the 15-year. So the 30-year is safer. Only choose the 15-year if you have a large emergency fund (6+ months of expenses) and stable income.

How much does a 1% lower rate save on a 15-year vs 30-year?

On a $300,000 loan, a 1% rate difference (6.8% vs 5.8%) on a 15-year term saves about $30,000 in total interest. But the monthly payment difference is about $165. You have to decide if the savings justify the higher payment.

Can I refinance from a 30-year to a 15-year later?

Yes. Many people buy with a 30-year, then refinance to a 15-year when their income increases. Refinancing costs 2-5% of the loan amount in closing costs. On a $300,000 loan, that is $6,000 to $15,000. You need to stay in the home long enough for the interest savings to exceed those costs. The break-even is usually 3-5 years.

What is the typical rate spread between a 15-year and a 30-year mortgage?

The 15-year is usually around 0.5% to 0.75% lower than the 30-year. The spread tends to narrow when rates are high and widen when rates are low. For where rates actually sit, check a daily source such as Freddie Mac's Primary Mortgage Market Survey, and above all get a quote from your own lender.

Should I take a 30-year mortgage if I plan to sell in 5 years?

Yes. The 15-year makes no sense for short-term ownership because the higher payment does not give you enough time to recoup the interest savings. On a 5-year hold, the 30-year is cheaper per month, and you will not pay the full 30 years of interest anyway.

How does the 30-year vs 15-year decision change with a higher down payment?

A larger down payment reduces the loan amount, which reduces the monthly payment difference. On a $200,000 loan instead of $336,000, the 30-year payment is $1,304, and the 15-year is $1,708. The difference is $404 per month, not $678. The total interest difference is $162,000 instead of $273,000. The 15-year is still attractive, but the cash flow impact is smaller.

Run the comparison yourself. Enter your numbers. See the real dollar difference. Then decide what works for your budget and your sleep-at-night factor.

Figures on this page are for educational purposes only. Rates, tax rates, and insurance costs vary by lender, location, and borrower profile. Consult a licensed lender for loan-specific figures. Truly Free Mortgage Calculator does not collect personal data and does not connect users with lenders.

Related Guides

Extra Mortgage Payment Calculator

How extra payments shave years off your loan.

Amortization Schedule Explained

See exactly where your money goes every month for 30 years.

Should I Refinance in 2026?

The break-even math on refinancing your current loan.

WRITTEN BY

George Smith

Founder, Klickify Agency

[email protected]LinkedIn

George builds free, client-side mortgage and financial calculators with transparent, formula-based methodology and zero data collection. Founder of Klickify Agency. Not a licensed financial advisor or loan officer — figures on this site are educational estimates; consult a licensed lender for loan-specific guidance.