Inheritance: Pay Off Mortgage or Invest?

You've inherited money. You have a mortgage. Should you pay it off, invest the inheritance, or split the difference? This calculator compares all three scenarios — showing projected net worth at your chosen horizon and the break-even investment return that tips the math one way or the other.

How to read these results

The break-even rate

This is the minimum after-tax investment return that makes investing financially better than paying off the mortgage. It equals your effective mortgage cost after the interest deduction (if you itemize).

If you don't itemize — which most people don't since the 2026 standard deduction is $16,100 for single filers and $32,200 for married filing jointly¹ — your break-even is just your mortgage rate. A 6.5% mortgage requires your investments to earn at least 6.5% to match the guaranteed return of payoff.

Net wealth from inheritance

This shows what your inheritance generates in net worth at the chosen horizon — investment portfolio value minus any remaining mortgage debt. In the "Invest All" scenario, the investment portfolio is fully funded but you still owe whatever remains on the mortgage at that point. In the "Pay Off" scenario, that debt is eliminated upfront, and the freed-up monthly payment is reinvested.

Gross return vs. mortgage rate: the right comparison

A common misconception is to compare your after-LTCG investment return to the mortgage rate. But long-term capital gains tax is deferred — you don't pay it annually, only when you sell. That means the correct break-even comparison is your gross expected return vs. your effective mortgage cost (after the interest deduction, if you itemize). At a 6.5% mortgage with no itemizing, you need your investments to return at least 6.5% gross to come out ahead by investing — not 6.5% ÷ (1 − 15% LTCG). The calculator's table gives you the actual net worth comparison so you don't have to rely on approximations.

What the numbers miss

The calculator gives you the arithmetic. A few things it can't quantify:

• Sequence of returns risk. The market can drop 30% right after you invest. A paid-off house cannot.
• Liquidity. Equity in a home is illiquid. If you pay off the mortgage and then need cash, you'll need a HELOC, cash-out refi, or sale. With the money invested, you can sell in days.
• Tax-advantaged space. If you haven't maxed Roth IRA, 401(k), or HSA contributions, investing the inheritance there makes the after-tax return advantage even larger — Roth growth is permanently tax-free.
• Emotional value. Many people value the certainty and simplicity of owning their home outright. That's real, even if it's not in a spreadsheet.
• Your income trajectory. If you expect income to rise significantly, today's mortgage deduction (if you itemize) is worth more than a future one at a higher bracket. If you're retiring soon, a paid-off home eliminates a required monthly expense.

The split strategy

Many advisors recommend a hybrid: use a portion of the inheritance to pay off the mortgage, invest the rest. This gives you debt elimination and some liquidity. The 50/50 split in the calculator illustrates this — but the right split depends on your risk tolerance, income stability, tax situation, and how much you value the insurance of a debt-free home.

Inherited IRA vs. taxable inheritance: different analysis

If part of your inheritance is an inherited IRA, the analysis is different. Inherited IRA funds are pre-tax money that must be distributed within 10 years under the SECURE Act. You cannot park inherited IRA distributions into a mortgage payoff in a tax-efficient way — those distributions are ordinary income when you take them, regardless of what you do with the cash. The "pay off vs. invest" decision applies cleanly to after-tax inherited assets: brokerage accounts, life insurance proceeds, savings, and real estate sale proceeds.

When to talk to an advisor

The calculation gets more nuanced when your inheritance includes a mix of asset types, when your income will change significantly over the next few years, or when the estate still hasn't fully settled. An advisor who specializes in inheritance planning can model your specific tax situation, coordinate the inheritance with your existing retirement accounts, and help you make a decision you'll be confident in — not one you'll second-guess in year 8.

Sources

1. IRS Rev. Proc. 2025-32 — 2026 standard deduction: $16,100 (single), $32,200 (MFJ)
2. IRS Topic 505 — Interest expense: mortgage interest deductibility rules
3. IRS Publication 936 — Home mortgage interest deduction
4. IRS Topic 409 — Capital gains and losses: long-term rates applicable to invested inheritance proceeds

Tax values verified against 2026 IRS guidance (Rev. Proc. 2025-32). Calculator uses gross investment returns; your actual after-tax return depends on account type (taxable vs. Roth vs. traditional), asset allocation, and tax lot selection. Consult a fee-only advisor for your specific situation.