Mortgage Payoff vs. Invest Calculator
Compare paying off a mortgage today with keeping the loan and investing available cash instead. The result shows modeled net wealth over the remaining mortgage term — not a personal recommendation.
Assumptions
Shared mortgage and market assumptions for both paths. Adjust these once and both scenarios update instantly.
Option 1
Pay off mortgage today
Use available savings to clear the mortgage balance now. The mortgage payment disappears, and the freed monthly cash flow can be invested over time.
The mortgage is cleared immediately, so the portfolio starts from zero and grows from monthly contributions after the payoff.
$1,148,528
$1,200 / mo
$0
$1,148,528
Option 2
Keep mortgage and invest
Keep the mortgage in place and invest the available lump sum instead. Mortgage payments continue, so the model tracks both the investment portfolio and the interest paid over the remaining term.
The mortgage stays in place while the same cash is invested upfront and tracked both gross and net of mortgage interest paid.
$2,291,947
$400 / mo
$109,094
$2,182,853
Option 2 wins on net wealth
$1,034,326
Keeping the mortgage and investing upfront ends at $2,182,853 net versus $1,148,528 for paying off the mortgage first.
This comparison is based on the assumptions above. It does not measure liquidity, risk tolerance, taxes, refinancing options, or the emotional value of being debt-free.
Portfolio comparison over time
Blue shows the payoff-first portfolio. Green dashed subtracts cumulative mortgage interest from the gross investment path.
Want to understand the math?
How to interpret this result
This calculator compares two paths over the same remaining mortgage term:
- Pay off the mortgage now — the debt is cleared immediately, then freed monthly cash flow is invested.
- Keep the mortgage and invest — the mortgage continues, while the available lump sum is invested instead.
The winner is based on modeled net wealth at the end of the term. That is useful, but it is not the whole decision.
What to watch
Mortgage rate vs. investment return
This is the main driver. Paying off debt is closer to a certain return equal to the mortgage rate. Investing offers a higher expected return only if the market performs well enough.
Net value, not gross portfolio value
A large investment portfolio can look attractive, but the mortgage path also includes interest paid over time. Net value is the fairer comparison.
Liquidity
Money used to pay off a mortgage becomes home equity. That can reduce stress, but it is less flexible than cash or investments.
Risk
Mortgage interest savings are relatively predictable. Investment returns are not. A result that favors investing under a 7% return may look very different at 4% or 5%.
Taxes and local rules
Mortgage deductions, capital gains taxes, and investment account rules can change the result. Treat tax inputs as simplified planning assumptions.
A simple way to use this calculator
Run the comparison three times:
- your baseline investment return
- a lower return assumption
- a higher mortgage rate or after-tax mortgage cost
If investing only wins under optimistic assumptions, the payoff path may deserve more weight.
Related reading
Methodology
Want the formulas and assumptions?
FAQ
Is paying off a mortgage the same as investing?
No. Paying off debt reduces interest costs. Investing keeps money in the market and introduces market risk.
Why does the investment path often look stronger?
Because a lump sum invested early has more time to compound. But that assumes the return is actually achieved.
Should I always choose the higher net wealth result?
No. Liquidity, risk tolerance, income stability, taxes, and peace of mind matter too.
Does this include taxes?
Only if tax assumptions are supported in the calculator. Real tax treatment depends on local rules and account type.
What if I do not have enough cash to pay off the mortgage?
Then this is not the right comparison. You would need an extra-payment-vs-investing calculator instead of a full payoff comparison.
Is this financial advice?
No. It is a planning model based on your assumptions.