Pay Off Mortgage or Invest? The Breakeven Math
The 10-year Treasury yields 4.67% risk-free. If your mortgage rate is below 4% — like 60% of homeowners — investing beats payoff before you even touch the stock market.
Pay Off Mortgage or Invest? The Breakeven Math for Homeowners With Extra Cash
You've got an extra thousand dollars a month and a mortgage. Should it go to principal — or your brokerage account? Most advice online still assumes you itemize your taxes and deduct mortgage interest. You probably don't. Nine out of ten filers take the standard deduction now, which completely changes the math. Here's the real breakeven for 2026.
Here's the short answer. The 10-year Treasury yield sits at 4.67%. The effective federal funds rate is 3.64%. That's a spread of just over one percentage point, and both figures are current as of May 19, 2026, from Federal Reserve data. The Fed's target range is 3.50 to 3.75%, so the 3.64% is the rate actually trading within that band. That narrow spread tells you the bond market expects rate cuts, which makes locking in 6.36% "returns" by paying off a new mortgage less attractive than it looks. But if your mortgage rate is below 4% — and 60% of mortgaged homeowners are below that line — the math flips hard toward investing.
Data as of May 19, 2026.
Key Takeaways
- Mortgage below 4%: Invest. Even risk-free 10-year Treasuries at 4.67% beat your loan rate, per FRED. - Mortgage at 6%+ AND you don't itemize: Paying down mortgage is closer to a wash, but most analysis still favors diversified equity investing for long horizons. - Best for retirees and risk-averse savers: Mortgage payoff. The guaranteed "return" plus cash-flow certainty beats market volatility once you're drawing income. - Best overall for working-age households: Capture the full 401(k) match first (averaging 4.6% of pay, per Vanguard's How America Saves), then split extra cash 70/30 between investing and mortgage based on rate.
Comparison Table
| Feature | Pay Off Mortgage | Invest in S&P 500 | Hybrid (Match + Split) |
|---|---|---|---|
| Effective return | Your mortgage rate (guaranteed) | ~10.42% long-run avg | 50% instant on matched dollars, then blended |
| Risk level | None (guaranteed) | Moderate–high | Low–moderate |
| Liquidity | Locked in home equity | Liquid (taxable) / locked (401k) | Mixed |
| Tax treatment | No deduction if standard deduction taken | 0–20% long-term capital gains (LTCG), or tax-deferred | Tax-advantaged on match |
| Standout feature | Removes a fixed monthly liability | Compounds for decades | Captures free money first |
| Biggest drawback | Illiquid, opportunity cost | Sequence-of-returns risk | More moving parts |
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Best overall: Hybrid strategy. Almost every household should max the employer 401(k) match first — the average match is 4.6% of pay and the most common structure is a 50% match on the first 6% of salary, per Vanguard. That's a 50% instant return on every dollar you contribute up to the match limit. Nothing about your mortgage rate competes with that.
Best for the risk-averse: Pay off mortgage. If a 40% drawdown would make you sell at the bottom — and most people overestimate their stomach for this — the guaranteed return of mortgage prepayment beats a higher expected return you won't actually capture. Behavior risk is real risk.
Best for working-age homeowners with sub-4% mortgages: Invest aggressively. 60% of mortgaged homeowners have rates below 4%, per FHFA research. Paying these off early is mathematically inferior to even Treasury bonds at 4.67% ((https://fred.stlouisfed.org/series/DGS10)) — let alone equities.
Option A: Pay Off Mortgage Early
When you make an extra principal payment, your "return" equals your mortgage rate — guaranteed, after-tax, with no market risk. That sounds great until you adjust for two realities.
First: most homeowners no longer itemize. The 2026 standard deduction is $32,200 for married filing jointly and $16,100 for single filers, per IRS Publication 936. Roughly 90% of filers take the standard deduction, which means the mortgage interest "tax shield" most calculators assume doesn't apply. Your 6.36% mortgage is a 6.36% cost — not 4.5% after fictional deductions.
Second: calling it a 6.36% return overstates what you actually get. You're avoiding a 6.36% cost on a shrinking balance — the absolute dollars saved drop every month as the principal you've already paid off stops accruing interest. Mathematically that nets out to the rate, but the money lands in illiquid home equity, not a brokerage account you can tap if you lose your job in month seven.
19.7% of mortgaged homeowners now carry a rate of 6% or higher — the highest share since 2015, according to Redfin. For this group, prepayment math is genuinely competitive with investing.
Pros:
- Guaranteed return equal to your mortgage rate
- Eliminates a fixed monthly liability
- Forces savings discipline
- Private Mortgage Insurance (PMI) becomes deductible as mortgage interest starting tax year 2026 under the One Big Beautiful Bill, per H&R Block — slightly raising the effective benefit of holding a mortgage with PMI
Cons:
- Money is locked in illiquid home equity
- No upside if markets outperform
- No tax shield if you take the standard deduction
- Inflation erodes the real cost of fixed-rate debt
Option B: Invest in a Diversified Portfolio
The S&P 500's trailing 10-year average annual return is 15.62% with dividends reinvested, per Slickcharts. The 100-year average is 10.42%. The inflation-adjusted 10-year average is 12.02%. Pick your number — but the 100-year figure is the most defensible for forward-looking planning.
Compare that to a new 6.36% mortgage, per Freddie Mac's PMMS. The historical gap is roughly 4 percentage points. Over 20 years on $200,000 of extra capital, that 4-point spread compounds into a six-figure difference.
But — and this is what most "invest instead" advice glosses over — the long-run average masks sequence-of-returns risk. A homeowner who started investing the difference in 2000 watched the S&P 500 lose 49% by 2002. The same investor in 2007 lost 57% by March 2009. A guaranteed mortgage payoff doesn't have a 50% drawdown scenario.
Consider a worked example. A homeowner with a 30325 = $390 in interest the first year, growing as the principal shrinks. After 20 years, the mortgage is paid off roughly 7 years early. - Invest: Put $1,000/month into a low-cost S&P 500 index fund. Run that thousand dollars a month through a compound-growth calculator at the S&P's 100-year average of 10.42%, over 240 months. You end up with roughly $802,000 after 20 years. After paying 15% in long-term capital gains tax, about $680,000 lands in your pocket.
At a 3.25% mortgage rate, investing wins by hundreds of thousands. At a 6.36% mortgage rate, the gap narrows considerably — and the risk-adjusted answer for someone who panics in a 30% drawdown shifts toward prepayment.
Pros:
- Higher expected long-run return
- Liquidity (in taxable accounts)
- Tax-advantaged compounding in 401(k) / individual retirement account (IRA)
- Diversification
Cons:
- Sequence-of-returns risk
- Behavioral risk (selling in drawdowns)
- Taxes on gains in taxable accounts (0% for married filing jointly under $98,900, 15% in the middle bracket, per IRS)
Option C: The Hybrid Approach
The honest answer for most working-age households: do both, in order. The hierarchy:
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- Emergency fund in a high-yield savings account. Top accounts pay up to 5.00% annual percentage yield (APY) at Varo on balances up to $5,000, with SoFi at 4.50% and Axos at 4.21%, per Fortune's May 2026 ranking. 2. Full employer 401(k) match. A 50% match on 6% of salary is a 50% instant return on the contributed dollars — non-negotiable. 3. Pay off high-interest debt (credit cards, anything above 8%). 4. Max tax-advantaged accounts (401(k), Health Savings Account, IRA). 5. Now compare mortgage rate to expected after-tax investment return. If your rate is below ~5%, invest in taxable accounts. If it's above ~6.5%, split the cash 50/50.
The hybrid wins because it sidesteps the two biggest mistakes in either pure strategy: leaving free match money on the table, and going all-in on equities right before a drawdown. Done in order, you bank the guaranteed wins (match, debt payoff, tax shelter) before exposing any dollar to market risk or locking it in illiquid equity.
The Real Breakeven Formula
Strip the analysis to its core. The decision flips when:
After-tax mortgage rate = After-tax expected investment return
For most non-itemizers, the after-tax mortgage rate equals the stated rate. For a long-term equity investor in the 15% capital gains bracket, the after-tax expected return is roughly 0.85 × 10.42% = 8.86%.
That means investing beats prepayment whenever your mortgage rate is below 8.86% — which, at current rates, is virtually every mortgage in America. The catch: this uses the 100-year average. If you assume a more conservative 7% forward return, the breakeven drops to 5.95% — and a new 6.36% mortgage edges into prepayment territory.
The takeaway: lock in your assumed forward return, multiply by (1 − your capital gains rate), and compare it to your stated mortgage rate. If the after-tax return is higher, invest. If it's lower, prepay. Everything else — peace of mind, sequence risk, behavioral durability — is a thumb on the scale, not the math itself.
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Pricing Breakdown
| Scenario | Mortgage rate | Recommended action |
|---|---|---|
| Sub-4% mortgage | < 4% | Invest aggressively |
| 4–5.5% mortgage | 4–5.5% | Invest, capture match first |
| 5.5–6.5% mortgage | 5.5–6.5% | 70/30 split: invest/prepay |
| 6.5%+ mortgage with PMI | 6.5%+ | 50/50 or prioritize prepayment until 20% equity |
| Within 10 years of retirement | Any | Lean toward prepayment for cash flow certainty |
How We Evaluated
Read our methodology at /how-we-evaluate/. For this comparison, options are scored on: (1) after-tax mathematical return at current market rates, (2) sequence-of-returns risk, (3) liquidity, (4) post-TCJA tax reality (standard deduction vs. itemized), and (5) behavioral durability — whether a real person can stick with the strategy through a downturn.
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Verdict
For most working-age homeowners with a sub-5% mortgage: invest. The math is overwhelming, and the 60% of homeowners sitting on below-market mortgages are holding a gift inflation will keep giving. Capture the full 401(k) match, fund tax-advantaged accounts, then build a taxable portfolio.
For homeowners with new 6%+ mortgages, especially those within 10 years of retirement: a split strategy or prepayment wins on a risk-adjusted basis. The expected-return edge for stocks narrows, sequence risk grows, and a paid-off house is the cheapest retirement plan there is.
Runner-up scenario: if you'd panic-sell in a 30% market drawdown, prepay. The best mathematical strategy is the one you'll actually follow.
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Frequently Asked Questions
Should I pay off my mortgage before retirement?
For most retirees, yes — but only after maxing tax-advantaged accounts. A paid-off mortgage reduces required monthly income in retirement, which lowers your tax bracket and Social Security taxation. Just don't drain your 401(k) to do it — that's a 22–24% tax bill to save 6% interest.
Does the mortgage interest deduction still matter?
For most filers, no. The 2026 standard deduction is $32,200 for married filing jointly, per IRS. Unless your mortgage interest plus state and local taxes plus charitable giving exceeds that, you take the standard deduction and the mortgage interest deduction is irrelevant to your actual taxes.
What if I have PMI?
PMI changes the math significantly. A 6.5% mortgage with 0.5% PMI is effectively a 7% loan until you hit 20% equity. Paying down to 20% equity to cancel PMI is one of the highest-return moves available to any homeowner — often beating equity returns.
How do current Treasury yields affect this decision?
The 10-Year Treasury at 4.67% , per FRED, sets a risk-free benchmark. Any mortgage below 4.67% is mathematically inferior to risk-free Treasuries — you're paying off a sub-Treasury loan with money that could earn more guaranteed elsewhere. The narrow 1.03-point spread between Treasuries and the EFFR suggests markets expect cuts, which would push these comparisons further in favor of investing.
Sources
- Federal Reserve Economic Data (FRED) — 10-Year Treasury Yield
- FRED — 30-Year Fixed Mortgage Rate
- FRED — Federal Funds Effective Rate
- Freddie Mac Primary Mortgage Market Survey
- IRS Publication 936 — Home Mortgage Interest Deduction
- Vanguard — How America Saves 2024
- FHFA — Lock-In Effect Working Paper 24-03
- Yahoo Finance — S&P 500
- Fortune — Best High-Yield Savings Accounts May 2026
This is informational, not financial advice — talk to a qualified financial advisor before making big debt or investment decisions. If you want the full rate-by-rate breakdown with the worked examples, head to canopy.press. And follow for more honest money math — no hustle culture, no hot takes, just the numbers.
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Found an error? At Canopy Press, accuracy comes first. If you spot a claim that needs checking, let us know at [email protected] — we'll verify and correct it immediately.
Sources
- FRED - 10-Year Treasury Yield
- FRED - 30-Year Fixed Mortgage Rate
- FRED - Federal Funds Effective Rate
- FRED - Consumer Price Index (CPI)
- FRED - Unemployment Rate
- Yahoo Finance - S&P 500
- Yahoo Finance - 10-Year Treasury Yield (Market)
- Yahoo Finance - CBOE Volatility Index (VIX)
- Yahoo Finance - US Dollar Index
- Yahoo Finance - Gold Price (per oz)
