EmpireSheets

Savings Goal Calculator

Two questions: how long at this rate, and how much a month to hit the date.

What this does

A goal is usually blocked by one of two unknowns: when you get there, or what it takes each month. This answers both from the same inputs, so you can move between them and find the version you can actually live with.

Why this one

It answers both directions of the same question on one screen. Most goal calculators do one and make you guess your way to the other by changing a number and pressing the button again.

The formula

how long:  run the balance forward a month at a time until it reaches the goal
how much:  shortfall / (((1 + rate) ^ periods - 1) / rate)
where shortfall is the goal less what the opening balance grows into by itself

Published so you can check it. A calculator about money that will not show its working is asking to be trusted on the one thing you cannot verify.

Questions

Why does it say the goal is never reached?
With no contribution and no growth, a balance below the goal stays below the goal. Saying never is more useful than showing a hundred year answer that looks like a plan.
What rate should I use for an emergency fund?
Whatever a high interest savings account is paying, and no more. Money you may need next month should not be somewhere its value can fall, whatever the projection would look like.