# How to Stop Auto Calculation in Excel

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*This tutorial demonstrates 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, you 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**.

- Now, select
**Formulas**and go to the**Calculation options**section. Here you can find the**Workbook calculation**settings. - Select
**Manual**. - Then click
**OK**.

## Manual Calculation: Calculate Now

To calculate formulas when auto-calculation is stopped, use **Calculate Now** in the Calculation Options. Let’s first see how data looks before calculating manually. For example, there are 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 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.