Why can the required monthly contribution be zero?

Under the entered return assumption, the estimated future value of current assets may already meet or exceed the target.

Why is the return field blank?

Portle does not choose a forecast for you. Enter the rate you want to test and compare more than one scenario.

Are monthly contributions made at the start of the month?

Yes. The calculation treats each contribution as arriving at the start of the month.

Target amount calculator

The same formula, solved backwards

The calculator first grows current assets under the entered return assumption. It then spreads the remaining target across start-of-month contributions over the selected period.

If the estimated value of current assets already reaches the target, the required monthly contribution is zero. That is a valid result, not a missing answer.

A target is not a forecast

Changing the return assumption can move the required contribution sharply. The result therefore repeats the rate entered and should be compared with a lower-return scenario.

Taxes, fees, drawdowns, and currency changes are not modeled. The calculation is a planning scenario, not a guarantee of arrival.