"Excel freezes when you open it" "No response as soon as you enter a formula" "Freezes for tens of seconds every time you save..." Have you ever experienced something like this?

There is not just one reason why Excel becomes slow, but a combination of factors such as how the file is created, PC specifications, and Excel settings. As of February 2026, this problem is still present in Microsoft 365 (formerly Office 365) and Excel 2021/2024.

This article provides an easy-to-understand explanation of 7 main reasons why Excel is slow or freezes and methods to make it lighter that you can try right now. You don't need any special software; you may be able to get it working just by changing the settings in Excel.

Let's have a rough understanding of how Excel becomes heavy in the first place

Roughly speaking, Excel becomes slow when the amount of processing exceeds the capacity of the PC.

Every time you change a cell value, Excel recalculates all related formulas. Additionally, if you have conditional formatting or graphs, it will also update their drawings. Microsoft's official documentation also explains that formula recalculation and drawing processing are the main causes of performance degradation.

In other words, The more complex the file, the heavier it becomes which is unavoidable to some extent due to Excel specifications. However, there are many cases that can be dramatically improved depending on how you do it.

7 reasons why Excel is slow or freezes

First, let's identify the cause. The following seven are typical causes.

Cause 1: File size is too large

Does the file size exceed several tens of MB due to pasting images, large numbers of data rows, or accumulation of unnecessary sheets? In general, if the size exceeds 10MB, Excel may become noticeably slower.

You can check the file size by right-clicking the file → "Properties".

Cause 2: There are a large number of formulas (VLOOKUP, SUMIFS, etc.)

When functions such as VLOOKUP, SUMIFS, and COUNTIF are copied over thousands of rows, the entire formula is recalculated every time you change a cell. Especially if you use VLOOKUP and set the search range to the entire column (A:A), it will be very slow as it will search all 1 million rows.

Cause 3: Too many conditional formatting settings

Conditional formatting is useful, but if it is widely applicable and has many rules, all rules will be evaluated each time a cell is displayed. Microsoft Learn also clearly states that ``excessive use of conditional formatting will significantly slow down calculation speed.''

You may have dozens of rules accumulated without realizing it, so be sure to check them.

Cause 4: Unnecessary add-ins are enabled

You can add third-party add-ins to Excel, but if unused add-ins are running in the background, they will consume memory and slow startup and operation.

Cause 5: Autosave interval is too short

By default, Excel saves data for automatic recovery every 10 minutes. If the file is large, it may freeze momentarily every time you save it. If your computer periodically freezes for a few seconds, this may be the cause.

Cause 6: Hardware graphics acceleration problem

Excel is set to use the GPU (graphics card) for drawing graphs and graphics, but if your PC's GPU driver is outdated or incompatible, drawing may become slower or freeze.

Cause 7: PC memory (RAM) is insufficient

If you open a large number of tabs in your browser in addition to Excel, or use Teams or Zoom at the same time, Even 16GB of memory may become stiff. Even with X, there was a comment that ``Windows quickly freezes in Excel if the memory is 16GB'' (February 2026).

Try checking the memory usage in the Performance tab of Task Manager (Ctrl + Shift + Esc). If it exceeds 80%, there is a high possibility that there is insufficient memory.

Try it now! 7 ways to make Excel lighter

Now that we know the cause, let's take a look at how to deal with it. We recommend trying them in order from the top.

Solution 1: Switch the formula calculation method to "manual"

If your file has a large number of formulas, try this first.

  1. Click on the Formula tab
  2. Select "Calculation method settings" → "Manual"
  3. If you want to recalculate, press F9 key

With this alone, the symptoms of freezing every time you edit a cell may disappear. However,if you forget to recalculate, the old value will remain, so make a habit of pressing F9 when checking the final result.

Solution 2: Limit the search range of VLOOKUP (or change to XLOOKUP)

If the second argument of VLOOKUP is specifying the entire column like "A:D", it will be faster just by narrowing down to the actual data range like "A1:D5000".

For Microsoft 365 or Excel 2021 or later, XLOOKUP function. XLOOKUP is more flexible than VLOOKUP and may offer better performance in some cases.

Solution 3: Organize and delete conditional formatting

  1. Click "Home" tab → "Conditional Formatting" → "Manage Rules"
  2. Change "Show formatting rules" to "This worksheet"
  3. Select the unnecessary rule and click "Delete rule"

Multiple rules often overlap in the same range. If you take the plunge and delete everything and then re-install only what you need, it will be much cleaner and lighter.

Solution 4: Disable hardware graphics acceleration

  1. Click "File" → "Options"
  2. Click "Advanced Settings" in the left menu
  3. Check Disable hardware graphics acceleration in the Display section
  4. Click OK and restart Excel

Effective when freezing a file that uses a lot of graphs or SmartArt.

Solution 5: Disable unnecessary add-ins

  1. Click "File" → "Options" → "Add-ins"
  2. In "Management" at the bottom, select "COM Add-in" and click "Settings"
  3. Uncheck
    4. unused add-ins

If you are not sure which ones are unnecessary, it is safe to remove them all, check how Excel works, and then add back only the ones you need.

Countermeasure 6: Increase the autosave interval

  1. Click "File" → "Options" → "Save"
  2. Change the value of "Save automatic recovery data every" from 10 minutes to 20 minutes

The symptom of "periodically freezing for a moment" can be resolved with this. However, in the unlikely event of a crash, you will lose more data, so make it a habit to frequently save manually using Ctrl+S.

Solution 7: Reduce file size

This is a checklist to eliminate file enlargement.

  • Delete unused sheets
  • Compress the pasted image (select the image → "Format" → "Compress picture")
  • Clear formatting outside the data range (select below the last row of data → Delete key)
  • Save in xlsb (binary format) instead of xlsx (file size will be much smaller)

Microsoft's official support page also provides detailed workbook cleanup instructions.

Last resort if the problem still persists

If the above method does not improve the problem, please consider the following.

Start Excel in safe mode

Open Run with Windows key + R, type excel /safe and press Enter. Safe mode starts with add-ins and customizations disabled, which can be used to isolate problems.

Run an Office repair

  1. Windows "Settings" → "Apps" → "Installed apps"
  2. Find Microsoft 365 (or Microsoft Office) and click Change
  3. Select "Quick Repair" and run it (if that doesn't work, "Online Repair")

Microsoft Official Support also recommends repairing Office if the freeze persists.

Consider adding memory to your PC

If the memory usage rate in Task Manager is always above 80%, closing the app will not solve the problem. In particular, it is quite difficult to use Excel and Teams at the same time on a PC with 8GB of memory. If possible, consider increasing the capacity to 16GB or more, or 32GB for business use.

FAQ

Can I force close Excel as soon as it becomes "unresponsive"?

Let's wait a moment. If Excel is just recalculating a large amount, it may recover after several tens of seconds to several minutes. Even if you see "Not responding" in the title bar, we recommend Waiting for about 5 minutes. If it still does not return, please terminate it from Task Manager. The automatic recovery function may restore previous data.

Wouldn't it become heavier if I migrated to Excel Online or Google Spreadsheets?

Since Excel Online runs in a browser, the memory load on your PC tends to be lighter. However, it does not support macros, VBA, or some functions, so migration may be difficult depending on the business content. Google Sheets can similarly become slow with large amounts of data (tens of thousands of rows or more).

Does the same problem occur on Mac?

Yes, the Mac version of Excel can also become slow due to the same reason. However, the operating procedures (menu location and shortcut keys) are different from the Windows version. The solutions in this article are based on the Windows version.

Are there any disadvantages to saving in xlsb (binary format)?

xlsb can significantly reduce file size, but it may have limited compatibility with Power Query or may not be readable by other tools. If the file is to be shared internally, please check its operation before migrating it. If it is a file for personal use, it is OK to use it actively.

References