# How to edit a formula

One thing you'll need to do in Excel is check and edit formulas to keep them in synch with other worksheet changes. Editing a formula in Excel is similar to editing other content. One difference is that you can update cell references using drag and drop.

Let's take a look.

Here we have a worksheet with some incorrect formulas. Let's check the formulas against the instructions to understand what's wrong.

A easy way to check a formula is to double click the cell. To get back out of edit mode without making changes, press Escape.

We can see that the first formula is adding the wrong cells together. It should be adding B7 to D9, but it's adding B7 to D6.

Let's press escape and look at the next formula.

The second formula is manually adding only the first 3 cells in F7:F10, so it's missing F10. And we really should use the SUM formula here.

The last formula is summing the range H8:H11. It's using the SUM function, which is good, but it's including an extra cell.

Now let's fix the problems.

To edit an existing formula, just double-click, and revise as needed.

Excel also a cool way to let you change cell references by dragging. If we undo our change, and then edit the cell again, we can just drag the reference to D6 onto cell D9, and press enter to confirm.

The next formula would be better rewritten using the SUM function. So we'll just replace the formula.

In our last example, we just need to adjust the range being used by the SUM function. We can do that by entering edit mode, and using one of the highlighted handles to size the range correctly.