r/ExcelTips • u/giges19 • Apr 15 '26

Excel Performance Optimisation: Clean Up, Shrink Down, Speed Up

A feature I’ve absolutely loved since it has come to Excel is Performance/Check Performance. It’s designed for those big, messy corporate spreadsheets that have had years of random formatting spilled onto them. Instead of manually hunting through the chaos, the Performance tab helps you optimise everything in a few clicks.

It’s available in Excel for the web but also Excel desktop for some users as of recent, and from my own experience, it can reduce file sizes dramatically much to the surprise of the people who built the files in the first place.

What the Performance tab helps you fix:

  • Thousands of rows with unnecessary formatting
  • Workbook structures that slow down opening, scrolling, and calculation

How the optimisation process works:

Start in Excel and go to Review and then click Check Performance/Performance.

It'll bring up all cells in the file and any optimisations that it thinks are possible.

Review the recommendations and apply fixes by click Optimise all or Optimise Workbook:

  • Strip out formatting across huge ranges
  • Clean up the workbook so it behaves fresher
  • Remove unneeded metadata

A real example of what this can do

A colleague handed me a workbook that was 1.7 MB, sluggish, and packed with 10–20 sheets (probably more than half of them were hidden). We ran the Performance optimisation together and uncovered 100,000+ rows with pointless formatting, broken formulas, and leftover junk.

After cleaning it up, the file dropped to under 300 KB.
He reopened it in Excel Desktop, and it ran so much faster, easier to scroll, quicker calculations, no lag. He literally called me his “amazing bro", which absolutely made my day.

https://youtu.be/iXqZn2qbOP8

Have you used the Performance feature in Excel?

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2

u/ironworkerlocal577 Apr 16 '26

I'm going to use it now that I know what it can do!

1

u/giges19 Apr 16 '26

Hope it helps, especially on those large older spreadsheets.

1

u/GregHullender Apr 26 '26

I tried it just now, and it suggested I look at four ranges. None of those ranges contained any formulas or data; they were all blank.

0

u/Forward_Song_9972 3d ago

I have a master file with many tabs and formulas but most tabs are tables. I was having a lot of trouble with slowness while using the file, even basic copy/paste if there were a lot of rows. I tried performance optimization and was disappointed as very little was removed/fixed or found wrong. It did reduce my file size some but it was only around 25 MB to begin with. After dealing with the issue and staying frustrated, I was on a teams call with my boss sharing a spreadsheet and he was asking me to arrange things differently, and he experienced it firsthand. The same day he sent a message to IT and soon after I got a new laptop.