Growth and tradeoffs
When Extra Mortgage Payments Beat Investing
Compare guaranteed interest savings with a market return assumption that may or may not happen.
Decision summary
Should you make extra mortgage payments or invest instead?
Short answer: On a $320,000, 6.5%, 30-year loan, $250 extra principal models $122,994 of interest avoided and a payoff in 22 yr 3 mo.
Why this example matters
Compare extra mortgage payments with investing using mortgage rate, assumed investment return, time horizon, risk, liquidity, and interest-savings tradeoffs.
Inputs used
- Mortgage balance: $320,000
- Mortgage rate: 6.5%
- Extra payment available: $250 per month
- Investment return assumption: 7%
- Time horizon: 10 years
- Tax, liquidity, and risk differences: reviewed separately
Engine-generated result
Calculated with the same engine as the Mortgage Calculator.
On a $320,000, 6.5%, 30-year loan, $250 extra principal models $122,994 of interest avoided and a payoff in 22 yr 3 mo. Investing that $250 instead at a hypothetical 7% for 10 years projects $43,271. Those results are not the same risk.
- Interest avoided by $250 extra (full loan)
- $122,994
- Payoff time with $250 extra
- 22 yr 3 mo
- 10-year $250/mo at 7% assumption
- $43,271
- 10-year contributions if invested
- $30,000
Headline figure: $122,994
Tradeoff to watch
What can change the answer
This scenario is most useful when you adjust one assumption at a time in the related calculator. The comparison cards below show which version of the decision deserves a second pass.
Step-by-step interpretation
- Treat extra mortgage payments as a reduction in a known interest cost. The benefit is linked to the mortgage rate and amortization schedule.
- Treat investing as an uncertain return. A 7% assumption is useful for modeling, but it is not guaranteed in any specific decade.
- Compare liquidity. Extra mortgage payments can be hard to access without selling, refinancing, or using a home equity product.
- Check household risk first. If the emergency fund is thin, keeping cash available may matter more than either option.
Scenario comparison
Extra mortgage payment
Offers clearer interest savings and faster principal reduction, but reduces liquid cash and may not be easy to reverse.
Invest the difference
Keeps money more flexible in many accounts and may outperform the mortgage rate, but the return is uncertain.
Common mistakes
- Comparing a guaranteed mortgage rate with an optimistic investment return as if they had the same risk.
- Sending all extra cash to the mortgage before keeping an emergency fund.
- Ignoring tax treatment, employer matches, and account withdrawal rules.
Disclaimer
This scenario is for education and planning only. It does not provide personalized financial, tax, legal, credit, mortgage, or investment advice. Real outcomes can differ because rates, fees, taxes, insurance, lender rules, market returns, and household circumstances vary. Read the full financial disclaimer.
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