Pay Off Mortgage Early or Invest? Math by Rate [2026]
Pay off mortgage or invest? Below 4% → invest. Above 7% → pay off. 4–7% → split. Break-even by rate + tax-deduction math. Worked $300K example [2026].
Paying more than the required monthly mortgage payment, with the extra applied directly to principal to shorten the loan and reduce total interest.
Example: Adding $300/mo to a $300,000 30-year mortgage at 6% saves ~$95,000 in interest and ends the loan ~7 years early.
The value of the next-best alternative given up when making a financial decision.
Example: Prepaying a 4% mortgage instead of investing in an index fund returning 8% has a ~4% annual opportunity cost.
The short answer: it depends entirely on your mortgage rate. For rates under 5%, invest. For 7%+, pay off. The 5-7% range is a gray zone where both answers can be defensible, and the "right" choice depends on risk tolerance and psychology.
We swept 5,000 (mortgage rate × equity return × horizon) scenarios in our mortgage prepay vs invest study and found the crossover sits within ~50 bps of the expected equity return. At today's ~6.7% mortgage rate, the answer depends entirely on whether you assume 5%, 7%, or 10% forward equity returns — see the data table for exact terminal-wealth gaps.
The pure math
- Paying off mortgage early = guaranteed return equal to your mortgage rate
- Investing in stocks = ~8-10% expected return but with volatility and risk
- If mortgage rate > expected investment return: pay off wins
- If mortgage rate < expected investment return: invest wins
Rate-by-rate breakdown (30-year horizon)
- 3% mortgage: invest. Historical stock returns (~10%) crush this. Paying off is essentially paying 3% to avoid 7%+ expected gain.
- 5% mortgage: mild tilt to invest. After tax benefits (if you itemize), effective rate is ~3.7%. Stocks still likely win but smaller gap.
- 6.5% mortgage (typical 2024-2025): close call. Split between both. Use the mortgage payoff calculator to see exact dollars and years saved from extra payments.
- 7.5%+ mortgage: pay off wins. Equity market expected return is 7-10% before taxes on gains — the risk-adjusted math favors payoff. Or consider a refinance calculator check first if rates have dropped.
What the math doesn't capture
- Psychological freedom of no mortgage — valuable for some, irrelevant for others
- Risk of job loss: paid-off mortgage reduces required monthly expenses dramatically
- Tax benefits: mortgage interest deduction is reduced after 2017 law changes, matters less now
- Liquidity: home equity is not accessible without selling or taking a HELOC
The hybrid approach most people should consider
- Capture 401(k) match (non-negotiable)
- Max Roth IRA if eligible
- Then split extra cash flow: ~60% toward investments, ~40% toward extra mortgage principal
- Adjust based on how close you are to retirement
Special case: near retirement
If you're 5-10 years from retirement, paying off the mortgage becomes more attractive regardless of rate. Lower required monthly expenses in retirement means smaller portfolio needed, and removes sequence-of-returns risk from your first years.
The big mistake
Choosing between payoff and investing is not the most common mistake. The most common mistake is doing neither — spending extra cash flow on lifestyle instead of either goal. Whichever you choose, automating the decision (extra principal payment OR auto-invest) is what actually builds wealth.
Frequently asked questions
Should I use tax refund for mortgage or investing?
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What about refinancing instead?
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Is paying off mortgage a guaranteed return?
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Plug in your own amounts with our free calculators.