Should I Recast My Mortgage or Invest the Money?

You’ve come into a lump sum (an inheritance, a bonus, proceeds from a sale) and you’re weighing two paths: put it toward your mortgage and recast for a lower payment, or invest it and aim for higher growth. There’s no universal right answer, but there’s a clear framework for deciding.

What recasting actually returns

When you recast, the “return” you earn is your mortgage interest rate. Every dollar of principal you pay down is a dollar you no longer pay interest on. If your rate is 6.5%, paying down principal is effectively a guaranteed, risk-free, tax-free 6.5% return.

That last part matters. Investment returns are taxed (capital gains, dividends), but mortgage interest savings are not. So a 6.5% mortgage payoff is roughly equivalent to earning more than 6.5% in a taxable brokerage account, depending on your tax bracket.

What investing might return

Historically, a diversified stock portfolio has returned around 7–10% annually over long periods, but that average hides enormous year-to-year volatility, and future returns are never guaranteed. Some years are up 25%, others down 20%. You’re trading certainty for the expectation of more.

After taxes, the expected real return on a stock investment narrows the gap with a high mortgage rate considerably.

The math, simplified

Compare your mortgage rate to your expected after-tax investment return:

Your mortgage rate	Likely better choice
3–4%	Investing usually wins over the long run
5–6%	A close call, depends on risk tolerance
6.5%+	Recasting is increasingly hard to beat

When rates were near 3%, investing was an easy call for most people. With rates elevated in 2026, the guaranteed return from recasting clears a high bar that the stock market can’t reliably beat after tax and risk.

Beyond the numbers

The math isn’t the whole story. Consider:

Liquidity. Money put into a recast is locked in your home equity. You can’t easily get it back without selling or borrowing against the house. Invested money stays accessible. If your emergency fund is thin, that flexibility has real value.

Risk tolerance. A recast guarantees a lower payment. Investing might do better, or might be down right when you need the money. If market swings keep you up at night, the certainty of a recast is worth something.

Risk tolerance. A recast guarantees a lower payment. Investing might do better, or might be down right when you need the money. If market swings keep you up at night, the certainty of a recast is worth something.

Existing investments. If you’re not yet maxing out tax-advantaged accounts like a 401(k) match or IRA, those often beat both options. Free employer matching is an instant 50–100% return.

A balanced approach

You don’t have to choose all-or-nothing. Many people split the difference: keep a healthy emergency fund, capture any employer 401(k) match, then use the remainder to recast. That captures the guaranteed return on your mortgage while keeping some liquidity and market upside.

Run your own comparison

Plug your real numbers into the recast vs invest calculator, which weighs the guaranteed return of recasting against an assumed investment growth rate so you can see the breakeven for your loan. Then use the main recast calculator to confirm exactly how much your payment and total interest would drop.

If you decide recasting is the move, our how to recast your mortgage guide walks through the process, and is recasting worth it covers the full tradeoff picture.