How to Fix Microsoft Excel Slow With Large Spreadsheets

What Causes This?

Excel usually slows down with large spreadsheets because it has to recalculate too many formulas, load large amounts of data into memory, or render heavy formatting and objects like charts, images, and conditional formatting rules. The problem is often worse when the workbook contains volatile formulas, links to other files, thousands of rows of formatting, or add-ins running in the background. On Windows PCs with limited RAM or too many startup/background apps, Excel can also become sluggish simply because system resources are stretched.

Common Symptoms

• Excel freezes or pauses when opening, saving, or scrolling through a workbook
• Typing into cells lags by a few seconds
• Formulas take a long time to recalculate
• Task Manager shows high CPU or memory usage from Excel
• Large workbooks trigger “Not Responding” messages

How to Fix It Manually

1. Check whether your PC is running low on memory or CPU

   1. Open Task Manager with Ctrl+Shift+Esc.
   2. Click More details if needed.
   3. On the Processes tab, look for Microsoft Excel and check its CPU, Memory, and Disk usage.
   4. If memory usage is very high, close other heavy apps like browsers, Teams, or Adobe programs before working in Excel.

2. Set Excel calculation to Manual for large workbooks

   1. Open Excel.
   2. Go to Formulas > Calculation Options.
   3. Select Manual.
   4. Press F9 only when you want to recalculate.
   5. This helps when the workbook contains many formulas that recalculate after every edit.

3. Disable unnecessary Excel add-ins

   1. In Excel, click File > Options > Add-ins.
   2. At the bottom, next to Manage, select COM Add-ins and click Go.
   3. Uncheck add-ins you do not need, then click OK.
   4. Repeat this for Excel Add-ins if needed.
   5. Restart Excel and test the workbook again.

4. Reduce workbook bloat

   1. Remove unused rows and columns, especially if formatting has been applied far beyond your real data range.
   2. Delete unnecessary conditional formatting rules from Home > Conditional Formatting > Manage Rules.
   3. Replace complex or repeated formulas with values where possible:
      • Copy the finished cells
      • Right-click
      • Choose Paste Special > Values
   4. Compress or remove large images, charts, and embedded objects you do not need.

5. Save the file in a modern format and test a local copy

   1. Click File > Save As.
   2. Save the workbook as .xlsx or .xlsb if appropriate.
   3. If the file is stored on OneDrive, SharePoint, or a network drive, save a copy to your desktop and open that version.
   4. If the local copy is faster, the slowdown may be caused by sync or network delays rather than Excel itself.

6. Update Office and restart Windows

   1. In Excel, go to File > Account > Update Options > Update Now.
   2. After updates finish, restart your PC.
   3. A restart clears stuck background processes and frees memory that Excel may need.

7. Try Excel in Safe Mode

   1. Press Windows key + R.
   2. Type excel /safe and press Enter.
   3. Open the large workbook.
   4. If Excel runs better in Safe Mode, an add-in or customization is likely causing the slowdown.

Fix It Automatically with Kudu

If you do not want to dig through Task Manager, startup apps, memory pressure, and background processes yourself, Kudu can help automate the cleanup. It can detect common Windows performance issues that make Excel sluggish with large spreadsheets and apply fixes that free up resources and improve responsiveness.

Download Kudu Free →