Extra Mortgage Payment vs Invest Calculator

About this calculator

Extra cash can go toward two competing goals: paying down a mortgage faster, which delivers a guaranteed return equal to the loan's interest rate, or investing it, which offers a potentially higher but uncertain return along with liquidity the mortgage payment doesn't give back. This is one of the most common personal-finance trade-off questions, and the right answer depends heavily on the gap between your mortgage rate and your expected investment return.

This calculator projects both paths — extra principal payments on the mortgage versus investing the same amount — over your chosen time horizon, using your mortgage rate and an assumed investment return, and compares the resulting net position. It helps homeowners see, in dollar terms, which strategy is likely to leave them further ahead given their specific rate and return assumptions, rather than relying on a generic rule of thumb.