15-year vs 30-year: the real trade-off

A shorter term costs more every month and far less overall. Here is the arithmetic on a real scenario, and the questions that decide which one is right for you.

Updated August 2026

A 15-year mortgage does two things at once: it forces a bigger payment and it removes half the years of interest. The first is a cash-flow problem, the second is a wealth question, and they pull in opposite directions.

The same house, both ways

On a $425,000 home with $85,000 down, taxes and insurance at TX averages:

  30-year at 6.69% 15-year at 5.96%
Total monthly payment $3,090 $3,760
Interest over the loan $449K $175.1K
Principal & interest only $2,192 $2,862

That is $670 more a month to save $273.9K in interest. Shorter terms also usually carry a lower rate, which is why the gap in interest is much larger than simply halving it.

Three questions that settle it

  1. Would the higher payment crowd out everything else? A 15-year mortgage you cannot comfortably carry is worse than a 30-year one you can.
  2. Do you want the option, or the obligation? A 30-year mortgage with extra payments gets most of the interest saving while letting you stop in a bad month. A 15-year term is a commitment you cannot unwind without refinancing.
  3. What else would the money do? If the difference would otherwise go into a matched retirement account, the mortgage is not automatically the better use.

Change the term below and the whole schedule reprices. The middle path — 30 years plus extra payments — shows up in the suggestion panel with its own numbers.

Where you are buying

Using Texas averages: 1.63% property tax and $3,400 a year insurance per $300k of cover. Both are editable below.

The home
$100k $2M
Down payment & term

No PMI at 20% or more down.

Your rate
Your quote
Enter your own

Weekly national averages for conventional loans with strong credit. Live from Freddie Mac Primary Mortgage Market Survey.

Rate data is 31 days old — it may have moved. Check the source before relying on it.

Property tax

1.63% of price a year · $577 per payment

Homeowner's insurance

$321 per payment

HOA fees

$0 per payment

Monthly HOA fee, common for condos and planned communities — not part of the loan.

Payment options Monthly

Voluntary principal on top of every scheduled payment.

Total monthly payment

$3,090 /mo

$2,192 principal & interest plus $898 taxes, insurance and fees

Loan amount
$340,000
Paid off
Sep 2056
Total interest
$449K

A dated roadmap from these numbers — on screen or as a 2-page PDF.

  • Principal & interest $2,192
  • Property tax $577
  • Homeowner's insurance $321
  • Total per month $3,090
Cash needed up front $93,500
Down payment (20%)
$85,000
Closing costs (estimate)
$8,500

Closing costs are a rough 2% of price. Actual legal fees, inspections and title costs vary by state.

Principal and interest per year over 30 years.
0$10K$20K$30K$40K$50K20262031203620412046205120552046: principal takes over
  1. 2026

    86% interest

    $22,635 of interest against $3,665 off the balance.

  2. 2046

    The balance tips

    Year 21: equity overtakes interest, $13,918 to $12,382.

  3. 2055

    Almost all yours

    Interest down to $929, with $425,000 of equity built.

  4. Lifetime

    $449K

    Total interest on this loan. A shorter term or bigger payments move it — priced below.

Hover or focus the chart and use the arrow keys to read any single year; every figure is also in the payment schedule.

What you can change

Built from your numbers — every one of these is this same calculation with a single input changed. Tap to try it; nothing is saved until you change it yourself.

  • Pay three extra payments a year

    Adding $548 to every payment pays this off 12 yrs 4 mos early and saves $208.9K in interest.

    Same loan, same rate — the extra goes straight at the principal.

    Interest saved $208.9KPaid off sooner 12 yrs 4 mos
  • Switch to accelerated bi-weekly

    Paying half your monthly amount every two weeks is one extra monthly payment a year: 6 years off the term and $106.2K less interest.

    26 payments of $1,096 instead of 12 of $2,192 — budget-neutral if you are paid every two weeks.

    Payment up $183/moInterest saved $106.2KPaid off sooner 6 years
  • Drop to 20 years

    A 20-year term raises your payment by $381/mo but cuts total interest by $171.5K.

    Paid off in Sep 2046 instead of Sep 2056.

    Payment up $381/moInterest saved $171.5KPaid off sooner 10 years
  • Watch for a half-point drop

    At 6.19% your payment falls $112/mo and you pay $40.1K less interest overall.

    That is the threshold where refinancing usually starts to pay for itself.

    Payment down $112/moInterest saved $40.1K

The point of all this

Turn these numbers into a plan

A dated roadmap built from your scenario and the moves worth making — on screen, as a two-page PDF, and saved so you can pick it up later.

Download PDF

Save your plan

Two pages, ready to print or send to a lender.

.pdf

Saves as mortgage-plan-us-425k.pdf

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AI

A personalized read on your numbers

The calculated moves below are always exact. This adds a prioritised, plain-language take on what your particular scenario calls for — written from the figures this calculator produced, not from figures the model made up.

One request, a few seconds. Nothing is stored.

Double-check this result

Run the same numbers somewhere else. Principal & interest should match to within a dollar or two; totals can differ because tools make different assumptions about PMI and whether HOA fees are included.

Total per month $3,090