There’s no answer that’s right for everyone. Each extra dollar you put on a mortgage earns a return equal to its interest rate, guaranteed: 3% on a 3% loan, 7.24% on a new loan at Freddie Mac’s average for October 29, 2026. Investing that dollar might earn more, but with risk, and the money in your home is harder to get back. The decision turns on four things: your rate, your taxes, your tolerance for risk, and how much cash you need to reach.
Your rate, against what safe money pays
The fairest comparison for a guaranteed return is another guaranteed return. Paying down a mortgage is like buying a bond that yields your mortgage rate, so start by comparing it with what US Treasuries pay.
If your rate is well below what Treasuries pay, prepaying gives up a safe return you could have kept liquid. If it’s well above, prepaying beats any safe alternative. Between the two, the other three factors decide it. Stocks may earn more than both over long periods, but with no guarantee and not in every decade. Any extra return is the pay for carrying that risk.
Taxes, on both sides
The mortgage side. Interest on the first $750,000 of home debt is deductible, but only if you itemize. For 2026 the standard deduction is $16,100 for a single filer and $32,200 for a married couple filing jointly, and state and local taxes count toward itemizing only up to $40,400 (less once income passes $505,000). If you take the standard deduction, your mortgage costs its full rate and prepaying earns its full rate. If you itemize, the after-tax rate is lower, which tilts things a little toward investing.
The investing side. Where the money would go matters as much as the rate. An employer match is an immediate return no mortgage can beat. Money in a 401(k) (up to $24,500 in 2026) or an IRA (up to $7,500) grows without yearly tax. Money in a taxable account pays tax on dividends and gains, so it has to earn more to keep pace.
Risk and liquidity
Prepaying is certain. Investing isn’t: a stock portfolio can fall sharply in the year you need the money. That doesn’t make prepaying the safer choice in every sense, because money put into a house is hard to get back.
- The payment doesn’t shrink. Extra principal shortens the loan but doesn’t lower your required monthly payment. If you lose your job, the equity doesn’t pay the bill.
- Borrowing it back isn’t guaranteed. Federal rules let a lender freeze or reduce a home equity line when the home’s value falls well below its appraised value or your finances change for the worse, which is when you’d most need it.
- Cash first. An emergency fund of several months of expenses comes before extra mortgage payments.
Near retirement the balance can shift. A paid-off home lowers the income you need each year, which some retirees value more than the return they gave up. Our guide to financial advisors for retirement covers that stage.
What prepaying does, in dollars
On a $300,000, 30-year fixed loan, paying $300 a month extra from the start:
| Rate | Paid off in | Interest saved |
|---|---|---|
| 3% | about 21.8 years | about $46,400 |
| 5% | about 21.3 years | about $91,700 |
| 7.24% | about 20.5 years | about $159,800 |
These are our calculations from standard amortization, with no tax effect. The same $300 a month invested could end up worth more or less than the interest saved, depending on returns.
When each choice tends to win
Paying down tends to win when:
- Your rate is above what safe investments pay, as with a loan taken out near today’s 7.24% average
- You already get the full employer match and have a solid emergency fund
- You take the standard deduction, so the interest gives you no tax break
- You’re close to retirement and want lower fixed costs
Investing tends to win when:
- Your rate is below Treasury yields, as with a loan locked in near 3%
- You’re not yet getting a full employer match, or have room in tax-advantaged accounts
- You have decades to ride out market swings
- You need the flexibility of money you can reach
Many people split the difference: invest enough to get the match and fill the accounts that matter most, then send some extra to the mortgage. That’s a reasonable answer, not a cop-out.
Common mistakes
- Prepaying while carrying credit card debt. Card rates are far higher. Pay those first.
- Ignoring a prepayment penalty. Federal rules allow one only on certain fixed-rate qualified mortgages, only in the first three years, and capped at 2% of the amount prepaid in years one and two and 1% in year three. Check your note.
- Counting the deduction you don’t take. If you don’t itemize, the mortgage has no tax advantage.
- Leaving yourself house-rich and cash-poor. A paid-down house with no savings is fragile.
Questions to ask an advisor
| Ask | A good answer includes |
|---|---|
| What’s my after-tax mortgage rate? | Whether I itemize, in dollars |
| What would the same money earn, after tax, where you’d put it? | The account type and a realistic range, not one number |
| How much cash should I keep before prepaying? | Months of expenses, tied to my job security |
| How are you paid, and does my choice change your fee? | A plain answer |
That last question matters. An advisor who charges a percentage of the assets they manage earns less when money leaves the portfolio to pay down a mortgage. A flat-fee or hourly planner earns the same either way. Our guide to flat fees vs a percentage of assets explains the pull each one puts on an advisor.
When advice is worth it, and what it costs
This is a good question for a one-off session. A fee-only planner who bills by the hour charges a median $300 an hour (middle half $250 to $350), and a one-time plan has a median of $2,000. It’s worth paying when the money involved is large, retirement is close, or the answer depends on taxes you can’t model yourself. If you already pay for ongoing planning, a median $4,500 a year among firms that publish prices, this question should be part of it. Advice-only planners give this kind of advice without managing money at all.
How to find one
In the public graph, see flat-fee advisors, advisors for pre-retirees and advisors for retirees, or browse pre-retirees and the retirement planning and tax planning specialties. Every record shows how the advisor is paid, so you can see who earns the same whatever you decide. If your debt is student loans rather than a mortgage, read pay off student loans or invest.