# How to Stop Auto Calculation in Excel

*In this tutorial, you will learn how to stop Excel from calculating automatically and the difference between automatic and manual formula calculation.*

## Stop Auto Calculation

By default, Excel recalculates every formula in a workbook whenever a cell is changed. This can slow down work, especially in complex files with a huge number of formulas. To speed up the process, we can** stop auto calculation** of formulas by changing it to manual. This means that formulas won’t be calculated automatically on every change in a workbook. There are two ways to achieve this. The first one is, in the **Ribbon**, go to **Formulas >** **Calculation Options** > **Manual**.

Another way to switch to the manual calculation is to change Excel settings.

First, open Excel and select **Options **at the end of the menu.

If you are already in an Excel Workbook, in the **Ribbon**, select **File > Options**.

1. Now, select Formulas and go to the **Calculation options** section. Here you can find the “Workbook calculation” settings.

2. Select **Manual**.

3. Then click OK.

## Manual Calculation – Calculate Now

In order to calculate formulas when the auto calculation is stopped, you need to use **Calculate Now** in the Calculation Options. Let’s first see how data looks before calculating manually. For example, we have numbers in Columns A and B and the sum of those numbers in Column C.

If you change numbers in Columns A and B while the auto calculation is set to Manual, you’ll see that sum in Column C does not update – no calculation is done.

So, when you’re ready to calculate all formulas, go to the (1)** Formulas **tab and click (2) **Calculate Now**.

Now all the formulas are updated, and the correct sums are calculated in Column C.