Down Payment Calculator

How the required monthly saving is derived

This calculator works in two steps. First, it projects your current savings forward, at the growth rate you assume, to the date you plan to have your deposit ready — money you've already saved keeps compounding whether or not you add to it. Second, it works out the fixed monthly contribution — itself also compounding at that rate — needed to close the remaining gap between that projected figure and your target deposit by the same date.

A longer timeline reduces the monthly amount required in two compounding ways: your existing savings have more time to grow on their own, shrinking the gap that needs to be closed, and whatever gap remains is spread across more monthly contributions, each of which also has longer to grow before the target date.

Worked example: 24 months vs. 48 months

Using the calculator's own defaults — a KES 1,600,000 target deposit, KES 200,000 already saved, and a 10% assumed annual growth rate — saving over 24 months requires KES 51,270 a month. Keeping every other input the same but stretching the timeline to 48 months brings the required monthly saving down to KES 22,174 a month — less than half, even though the target and starting point are identical, because the existing savings compound for twice as long and the remaining gap is spread over twice as many contributions.

The growth rate is arithmetic on the assumption you enter, not a quoted product return or a guarantee — not investment advice. Where you actually hold these savings, whether a bank account, a money market fund, or elsewhere, will determine the real rate you earn, so edit the field to match your own situation before relying on the result.