Interest with and without an extra payment

The debt screen compares interest and time at your minimums with interest and time after the extra is split.

Two scenarios

One scenario pays only the minimums. The other adds the extra, shared by those minimums. Total interest is computed for each. The difference is the interest the extra avoids.

Time saved is the change in how long the last debt takes. A debt that never pays off in the first scenario and does pay off in the second is a change in kind, not only in months.

Per extra dollar

When the extra is above zero, the screen can show interest saved per extra dollar. That is the interest difference divided by the extra monthly amount. It is a way to see the scale. It is not a bank yield.

The figure uses this split. A different targeting order would save a different amount, and this tool is not showing that other order.

The month uses the with-extra picture

The household debt total is minimums plus extra. Leftover shrinks by that whole amount, including the extra you chose to send.

The payoff lines use the with-extra payments. They match the second scenario, not the minimums-only one.

This explains how WiseCalculator treats the numbers you type. It is not a lender’s offer and it is not advice for your loan.