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Invest vs Pay Off Mortgage Calculator

Compare directing extra cash to investments versus using it to accelerate mortgage payoff.

Best used for

Shows how much interest you may save by paying extra toward the mortgage.

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Housing & Debt

Invest vs Pay Off Mortgage Calculator

Compare directing extra cash to investments versus using it to accelerate mortgage payoff.

Snapshot
Investing the extra cash may grow to about $126,785 over 15 years.
Over the same 15-year horizon, extra mortgage payments may save about $42,842 of interest, while investing the same $400 monthly may grow to about $126,785.
Investment value
$126,785
Mortgage interest saved
$42,842
Your Numbers
Your current mortgage or home loan balance.
$
Interest rate
Your current annual mortgage interest rate.
5.85
Original remaining term used for the standard payoff schedule.
Your regular monthly principal and interest payment.
$
Cash available either for investing or extra mortgage payments each month.
$
Investment return
Expected annual after-fee portfolio return.
7
Years
Projection length.
15
The month you want the payoff schedule to begin.
Results
Investing the extra cash may grow to about $126,785 over 15 years.
Over the same 15-year horizon, extra mortgage payments may save about $42,842 of interest, while investing the same $400 monthly may grow to about $126,785.
Investment value
$126,785
Mortgage interest saved
$42,842
15-year horizon
Difference
$83,943
Extra monthly cash
$400

Projection outlook

See how the modeled path evolves over time under the current assumptions.

Projected balance
Total contributions

Optimistic currently leads conservative by about $44,447.

Important findings
What the current inputs suggest
Over the same 15-year horizon, extra mortgage payments may save about $42,842 of interest, while investing the same $400 monthly may grow to about $126,785.
What changes the result most
Optimistic currently leads conservative by about $44,447, so the outcome is meaningfully sensitive to your assumptions.
How to use this result
Use the headline to frame the decision, then check the supporting metrics and timeline before acting. The output is strongest as a planning tool, not as a guarantee.

How it works

The calculation, without the clutter

1

The calculator runs one path with extra mortgage payments and one path that leaves the loan unchanged while investing the same extra cash instead.

2

It then compares mortgage interest savings with the projected investment account value over the chosen horizon.

Where this tool is most useful

A household with a mid-5% mortgage and a solid emergency fund may be choosing between a guaranteed debt-reduction return and the possibility of stronger long-term investment growth.

Key assumptions

What to sanity-check

  • The investment side assumes a steady annualized return rather than real market volatility.
  • The mortgage side assumes extra payments go directly to principal.
  • Taxes on investment gains are not modeled in detail.

Companion guide

How much do I need to retire?

A practical approach to estimating your retirement number without overcomplicating the first pass.

Read the guide

FAQ

Common questions

Are these outputs guarantees?

No. They are planning estimates based on your assumptions and should be updated as markets, taxes, and spending change.

Do these calculators replace professional advice?

No. They are a strong planning starting point, but tax, legal, and investment decisions should be reviewed with a qualified professional when appropriate.

How often should I revisit my inputs?

A good rule is to revisit assumptions after major income, spending, family, tax, or market changes and at least a few times per year.

Why do the optimistic and conservative scenarios matter?

They help you see how sensitive the result is to assumptions instead of anchoring on one exact output.

Invest vs Pay Off Mortgage | WealthyNest