The contribution does the work
For most realistic savings goals — a deposit, a car, a buffer — the monthly amount matters far more than the rate. At 6% over three years, interest contributes a few percent of the total. The tool shows the no-interest figure beside the real one so that ratio is visible instead of imagined.
Interest starts to dominate at long horizons and large balances, which is the territory of the compound interest calculator rather than this one.
Setting a target you will actually hit
Two failure modes. Setting the target in today's money for a goal a decade away means arriving with less than you planned. Setting a monthly contribution you cannot sustain means the plan quietly stops in month four.
The second is more common. A smaller amount that survives contact with a bad month beats a larger one that does not.
An emergency fund is not an investment
Money you may need at short notice belongs somewhere accessible, and the rate on it is close to irrelevant. Use this to work out how long the buffer takes to build; use a different tool for money you will not touch for years.
Questions
Why does it show months without interest too?+
So the contribution of interest is visible rather than assumed. Over short horizons at modest rates the two figures are nearly identical — which means the rate is not what gets you there, the monthly amount is.
What does "out of reach" mean?+
That the plan never reaches the target: no contribution and no interest, or a horizon beyond a hundred years. Showing a number there would be worse than saying so.
Should I include inflation?+
For a goal more than a few years out, yes. A target of a million in ten years is not a million in today's money. Set the target in future terms, or check what today's figure becomes with the [inflation calculator](/t/inflation-calculator).
Does it assume the rate stays fixed?+
Yes. Deposit rates move, and a savings account paying well today may not in three years. The result is a projection under one assumption, not a schedule.