Here we have a simple table for a driving trip across the United States.
The route begins in San Francisco and ends in New York City.
The route is divided into segments, with each segment starting and ending in a larger city.
Let’s add formulas in columns E and F to calculate the estimated fuel usage and fuel cost.
Let’s say we think our car will get 25 miles per gallon on average.
We can write the formula as D7 divided by 25, and then copy it down.
In column F, we need to calculate cost.
Let’s assume that gas will cost about $2.50 a gallon.
In that case, the formula becomes E7 * 2.50.
So these formulas work fine.
But what if you want to change the assumptions?
In that case you’ll need to edit all the formulas to reflect these new assumptions.
But still, you’ll need to touch every formula in the worksheet.
And if you change the assumptions, you’ll need to do it all over again.
In a more complicated worksheet, this can be a lot of tedious work.
A better approach is to expose the assumptions on the worksheet where they can be easily seen and modified.
Now I can modify the formulas to use these inputs instead of the hard-coded values.
Now I can easily change the assumptions and all formulas automatically recalculate.
There’s no need to edit any formulas.
This will make your worksheets easier to understand, more professional, and more durable overall.
