15-Year or 30-Year Mortgage?
A 15-year or a 30-year mortgage, with the difference invested: which leaves more? Every piece below can be linked to, so it opens in a window on your reader's screen, current as of the record. No form to fill in.
2026 law · Reviewed September 7, 2026 · The full page, with methodology and sources · the terms · All tools
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The loan, the two rates, the return, the tax on it, and the year to compare in; both payments, the difference, the interest each way, the positions at year 15 and year 30, the two paths drawn as lines, and the break-even return out. In a frame it carries no cookies, no tracking, and a visible link back to the methodology. Your site has to allow frames; most do. The link that opens it in a small window is on the professionals page.
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- In plain words.
- A 15-year loan has a lower rate and a higher payment, and it ends in half the time. A 30-year loan has a lower payment, and a borrower who invests the difference every month builds something on the side. This tool spends the same money on both paths. On the first the 15-year payment goes to the loan, and after the loan is gone the whole payment is invested. On the second the 30-year payment goes to the loan and the difference is invested from the start. It shows what each path holds, less what it still owes, at year 15, at year 30, and at a year you choose, and the return that would make them equal.
- Why it matters.
- It is the first decision on most mortgages and it is usually made on the payment alone. The payment is real, but so is the return the difference could earn, and the tool puts a number on both so the choice is about the rate gap and the risk rather than the monthly figure.
- An example.
- $400,000 at 6.5% for 30 years or 6.0% for 15, with a 7.0% return on the difference: the payments are $3,375.43 and $2,528.27, $847 a month apart. At year 30 the 15-year path holds about $1,069,883 and the 30-year path about $1,033,505, so the 15-year is ahead by about $36,378 at that return. The break-even return is 7.3%.
- Where it stops.
- The return is a guess, and it decides the answer. The tool holds the rates and the return steady, assumes the difference is actually invested every month, and takes tax from the return only at the rate you set. It leaves out the mortgage interest deduction, closing costs that differ between the two loans, mortgage insurance, and the value of a lower payment when income falls.
The facts
Six quotable sentences on the 15-year against the 30-year.
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- A 15-year mortgage carries a lower rate and a much higher payment, and it is done in half the time. On $400,000 at 6.0% the payment is $3,375.43, against $2,528.27 at 6.5% over 30 years, and the interest over the life of each loan is $207,577 against $510,178.
- The interest gap is not the answer, because the 30-year borrower has the difference every month to do something with. The fair comparison spends the same cash on both paths: the 15-year borrower pays the loan off and then invests the whole payment for the next fifteen years, while the 30-year borrower invests the difference from the first month.
- With the same rate on both loans and a return equal to it, the two paths tie to the cent at every month: $1,057,680 each at year 30 in the example. Everything that separates them is the rate gap between the two loans and the gap between the 30-year rate and the return.
- Example: $400,000 at 6.5% for 30 years or 6.0% for 15, with the $847 monthly difference invested at 7.0%. At year 15 the 15-year borrower owns the home clear, while the 30-year borrower holds $268,516 of investments against $290,237 still owed. At year 30 the 15-year path holds $1,069,883 and the 30-year path $1,033,505.
- The return that makes the two paths equal at year 30 in the example is 7.3%. Below it the 15-year leaves more; above it the 30-year does. Choosing the 15-year is a guaranteed return on the payment difference at that break-even rate, which sits at or above the 30-year rate because the whole loan is cheaper. Choosing the 30-year is a bet that the investment beats it.
- The arithmetic does not price the rest. The 30-year payment is a floor that can always be paid down faster, so it buys room for a lost job or a bad year. The 15-year payment is a commitment, and the equity it builds cannot be spent without selling or borrowing. Many households take the 30-year and pay it as a 15, and keep the choice.
By the expected return
How the answer moves with the one assumption that decides it.
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| Expected return | 15-year, then the payment invested | 30-year, the difference invested | Which leaves more at year 30 |
|---|---|---|---|
| 5% | $902,214 | $705,052 | The 15-year, by $197,162 |
| 6% | $981,637 | $850,980 | The 15-year, by $130,657 |
| 7% | $1,069,883 | $1,033,505 | The 15-year, by $36,378 |
| 8% | $1,168,027 | $1,262,566 | The 30-year, by $94,539 |
| 9% | $1,277,281 | $1,550,924 | The 30-year, by $273,643 |
Cite and link.
The clean address, a citation generated from the record so it can never carry a stale review date, and an address for every section so you can point a reader at the exact table or method.
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- Link
- https://consideratecapital.com/tools/15-or-30-year-mortgage
- Citation
- Considerate Capital, "15-Year or 30-Year Mortgage?," reviewed September 7, 2026, https://consideratecapital.com/tools/15-or-30-year-mortgage.
Link to a section
- The calculator https://consideratecapital.com/tools/15-or-30-year-mortgage#calculator
- The facts https://consideratecapital.com/tools/15-or-30-year-mortgage#facts
- By the expected return https://consideratecapital.com/tools/15-or-30-year-mortgage#key-numbers
- How the comparison works https://consideratecapital.com/tools/15-or-30-year-mortgage#how-it-works
- Methodology https://consideratecapital.com/tools/15-or-30-year-mortgage#methodology
- Revision history https://consideratecapital.com/tools/15-or-30-year-mortgage#revision-history
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