This question gets oversimplified fast. Paying extra on a mortgage can be a guaranteed reduction in interest owed. Investing can produce a higher return, but it comes with market risk and no promise that the timing will be polite.
Compare the mortgage rate to realistic investment returns
If your mortgage rate is high, extra payments may look more attractive. If your rate is low, investing may have a better long-term case. But do not compare a guaranteed mortgage rate to an imaginary best-case investment return.
Keep liquidity in mind
Money sent to the mortgage is harder to get back. Money invested in a taxable account is usually more flexible, though it can lose value. If your emergency fund is thin, locking up extra cash in the house may not feel great later.
Risk tolerance matters
Some people sleep better knowing the mortgage balance is falling faster. Others are comfortable investing for a potentially higher return. Both can be rational. The wrong answer is the one that keeps you anxious or cash-poor.
Do not ignore time
If you plan to move soon, extra principal payments may not feel as meaningful. If you plan to stay for decades, the interest savings can be more noticeable.
An extra $200 a month toward principal can cut interest and shorten the loan, but $200 invested monthly may grow more over time. The tradeoff is certainty versus potential.
Good places to double-check
Look at your mortgage rate, remaining term, emergency savings, and investment timeline. For tax or investment advice, use a qualified professional who can see your whole picture.