"What's it worth to reduce my spending?" shows how the amount you save today from spending less grows if invested instead. Future amounts are shown for 10 years and for the number of years until you retire.
The calculator lets you estimate how much you can save in a year by reducing spending for a range of categories. This includes postponing a decision to buy a new car, eating out less often, and cutting other non-essential expenses.
For example, if you reduce the amount you spend in a year eating out by $600 ($50 a month), you can invest that savings. This will grow to an amount that you can spend in the future.
By spending today, you are sacrificing future spending. The future amount that you sacrifice is the opportunity cost of spending today.