Excel Is Slow: 12 Methods for Faster Performance

Excel shows “Calculating…” for several seconds every time you change something. Saving takes a minute. Scrolling is jerky. You are not alone — slow Excel is the most common performance problem we see at Excel Department.

This guide gives you twelve proven optimisation methods. Most take a few minutes to implement and can deliver 50-90 percent faster performance. We start with the quickest fixes and then go deeper.

For quick solutions to other problems, see common Excel problems. For systematic troubleshooting, read the Excel troubleshooting guide.

Quick diagnosis: Why is your Excel slow?

Before you optimise, you need to understand where the bottleneck is.

Measure current performance

Test 1: How long does recalculation take?

1. Add a cell somewhere: =TEXT(NOW(),"HH:MM:SS")
2. Press F9 (force recalculation)
3. How long does it take?

Result: – Under 1 second: OK – 1-5 seconds: Can be optimised – Over 5 seconds: Critical, must be fixed

Test 2: How large is the used range?

1. Press Ctrl+End
2. Does the cursor land far from your actual data?

If Ctrl+End jumps to column Z row 10,000 but your data ends at column F row 500, Excel thinks the file is much larger than it is.

Identify common bottlenecks

Method 1: Eliminate volatile functions

Severity: High Time required: 15-30 minutes Expected improvement: 40-80%

Volatile functions are recalculated on every change in the workbook, not just when their precedents change.

Common volatile functions

NU()           ← Räknas om kontinuerligt
IDAG()         ← Räknas om kontinuerligt
INDIREKT()     ← Räknas om kontinuerligt
FÖRSKJUTNING() ← Räknas om kontinuerligt
SLUMP()        ← Räknas om kontinuerligt
SLUMPMELLAN()  ← Räknas om kontinuerligt

Find volatile functions

1. Press Ctrl+F
2. Select “Options”
3. Look in: “Workbook”
4. Search for: INDIRECT(
5. Repeat for the other functions above

Replace with non-volatile alternatives

INDIRECT → INDEX/MATCH

Before (volatile, slow):

=INDIREKT("Blad1!A"&RAD())

After (non-volatile, fast):

=INDEX(Blad1:Blad1;RAD();1)

OFFSET → Structured references

Before (volatile):

=SUMMA(FÖRSKJUTNING(A1;0;0;10;1))

After (non-volatile): Turn the data into a table (Ctrl+T):

=SUMMA(Försäljning[Belopp])

NOW/TODAY → Calculate once

If you only need today’s date when opening:

1. Type =TODAY() in a cell
2. Copy the cell (Ctrl+C)
3. Right-click → Paste Special → Values
4. Now the date is hardcoded (does not update)

Or use Ctrl+; to insert today’s date directly as a value.

RAND → Generate and copy as values

If you need random numbers that don’t change:

1. Generate with =RANDBETWEEN(1,100)
2. Copy the column
3. Right-click → Paste Special → Values
4. Now the random numbers are fixed

Method 2: Simplify complex formulas

Severity: High Time required: 30-60 minutes Expected improvement: 30-60%

A mega-formula calculates more slowly than several simple formulas that do the same thing.

Split into helper columns

Before (one complex formula):

=SUMMA(OM((MÅNAD(A2:A1000)=1)*(B2:B1000="Produkt A");C2:C1000;0))

After (several simple formulas):

Kolumn D: =MÅNAD(A2)
Kolumn E: =(D2=1)*(B2="Produkt A")
Kolumn F: =C2*E2
Resultat: =SUMMA(F2:F1000)

Excel calculates faster with five simple calculations than with one complex one.

Use tables instead of array formulas

Before (array formula with Ctrl+Shift+Enter):

{=SUMMA(OM(Region="Syd";Försäljning;0))}

After (table with structured reference):

=SUMPRODUKT((Försäljning[Region]="Syd")*(Försäljning[Belopp]))

Or better still — use a pivot table for summaries.

Method 3: Avoid whole-column references

Severity: Medium-high Time required: 10-20 minutes Expected improvement: 20-40%

When you refer to A:A, Excel calculates with all 1,048,576 rows.

Before and after

Before (slow):

=SUMMA(A:A)           ← 1 miljon rader
=ANTAL.TOMMA(B:B)      ← 1 miljon rader
=LETARAD(E1;A:B;2;0)   ← 1 miljon rader

After (fast):

=SUMMA(A2:A1000)              ← 999 rader
=ANTAL.TOMMA(B2:B1000)         ← 999 rader
=LETARAD(E1;A2:B1000;2;0)      ← 999 rader

Even better: Use tables

Turn the data into a table (Ctrl+T):

=SUMMA(Försäljning[Belopp])

Now the reference grows automatically when you add rows, but only calculates with actual data.

Method 4: Convert formulas to values

Severity: High (if historical data) Time required: 5 minutes Expected improvement: 50-90%

If the data doesn’t need to be updated — convert it to values.

When it is appropriate

• Historical reports (January data doesn’t need to be recalculated)
• Imported data that doesn’t change
• Calculations that are finished

How to do it

1. Select the column with formulas
2. Copy (Ctrl+C)
3. Right-click → Paste Special → Values (Ctrl+Alt+V → V)

Now the formula has been replaced by the result. No calculation time any more.

Warning: You can’t undo after you have saved. Save a copy first if the data might be needed as formulas later.

Method 5: Remove unused rows and columns

Severity: Medium Time required: 5 minutes Expected improvement: 10-30%

Excel stores a “used range” internally — even if cells are empty.

Reset the used range

1. Press Ctrl+End — does it land far from your data?
2. Select all empty rows below your data:
   • Click the first empty row number
   • Press Ctrl+Shift+Down (selects to the end)
3. Right-click → Delete
4. Repeat for columns (Ctrl+Shift+Right)
5. Save, close, open again

Excel now resets its internal range and the file becomes smaller.

Method 6: Clean up conditional formatting

Severity: Medium Time required: 10 minutes Expected improvement: 15-30%

Conditional formatting is recalculated on every change and can pile up over time.

Check the number of rules

1. Home → Conditional Formatting → Manage Rules
2. Select “This Workbook” in the drop-down
3. How many rules are there? Over 50? That’s a problem.

Clean up and consolidate

Remove duplicates: If the same rule exists several times, remove the duplicates.

Consolidate ranges: Instead of 20 rules on small ranges, create one rule for the whole area.

Remove unused ones: If the formatting is no longer needed, delete the rule entirely.

Alternative: If the formatting is static (doesn’t change), convert it to ordinary formatting: 1. Copy cells with conditional formatting 2. Paste Special → Formats 3. Remove the conditional formatting

Now you get the same look without the calculation cost.

Method 7: Remove or minimise charts and objects

Severity: Low-medium Time required: 10 minutes Expected improvement: 10-20%

Every chart is recalculated when data changes.

Find all objects

1. Press Ctrl+G
2. Click “Special”
3. Select “Objects”
4. Click OK

Now all charts, pictures, buttons, etc. are selected.

Optimise

Remove unused ones: If you have 20 charts but only use 5, delete the rest.

Reduce data points: Charts with 10,000 data points are slow. Aggregate to 100-200 points instead.

Use sparklines: For small trend displays, sparklines are much faster than charts.

Method 8: Save in binary format (.xlsb)

Severity: Low-medium Time required: 1 minute Expected improvement: 50-70% smaller file size, faster opening/saving

Binary format compresses data more than standard .xlsx.

How to do it

1. File → Save As
2. Select “Excel Binary Workbook (*.xlsb)”
3. Save

Benefits

• 50-70% smaller file size
• Faster to open and save
• All functions work normally
• Macros work (as with .xlsm)

Drawbacks

• Can’t be opened in Google Sheets
• A somewhat less widespread format

Method 9: Disable automatic calculation (temporarily)

Severity: High (when building models) Time required: 10 seconds Expected improvement: 100% (Excel doesn’t calculate at all)

When you build or edit large models you can turn calculation off temporarily.

Enable manual calculation

1. Formulas → Calculation Options → Manual
2. Make your changes
3. Press F9 when you want to recalculate
4. Don’t forget to switch back to Automatic when you are done

Keyboard shortcuts: – F9: Recalculate the whole workbook – Shift+F9: Recalculate the current sheet – Ctrl+Alt+F9: Force a full recalculation

Warning: Don’t forget to switch back to Automatic. Otherwise you will get old values when you change data.

Method 10: Remove external links

Severity: High Time required: 15-30 minutes Expected improvement: 30-60% faster opening

External links to other files make opening slow, especially if those files are on network drives.

Find external links

1. Data → Edit Links
2. If nothing happens: There are no external links
3. If the dialog box opens: The list shows all linked files

Remove or break links

Option 1: Break the link 1. Select the link in the list 2. Click “Break Link” 3. Excel replaces formulas with values

Option 2: Find and replace manually 1. Ctrl+F 2. Look in: Workbook 3. Search for: [ (start character for an external reference) 4. Find all cells with external references 5. Replace formulas with values or repoint to local data

Method 11: Disable add-ins

Severity: Medium Time required: 5 minutes Expected improvement: 10-40% faster start-up

Add-ins are loaded at start-up and can slow Excel down.

Check active add-ins

1. File → Options → Add-ins
2. At the bottom: Select “COM Add-ins” → Go
3. The list shows all active add-ins

Disable unused ones

Untick add-ins you don’t use. Common “culprits”: – Adobe Acrobat integration – Old Analysis ToolPak – Third-party add-ins

Test: Start Excel in safe mode (excel /safe) to see performance without add-ins.

Method 12: Use Power Query for data import

Severity: High (for files with external data) Time required: 30-60 minutes (one-off work) Expected improvement: 50-90% for import workflows

If you import data from CSV, databases or other sources repeatedly.

Why Power Query is faster

• Data is loaded only when you refresh (not continuously)
• Efficient compression
• Transformations are done once, not with formulas

How to migrate

1. Data → Get Data → From File/Database
2. Select the data source
3. Build transformations in the Power Query editor
4. Click “Close & Load”

Now you can delete all the import formulas and replace them with a Power Query query.

Read more: Power Query for Excel

Bonus: Professional performance optimisation

If you have tried everything above and Excel is still slow, the problem may be more complex.

Signs that you need expert help

• File size over 50 MB despite a reasonable amount of data
• Calculation time consistently over 10 seconds
• Excel crashes regularly
• Problems affect several users/files

What we offer at Excel Department

Performance analysis: We analyse your file with professional tools and identify exactly where the bottleneck is.

Restructuring: We rebuild the solution for optimal performance — often 10-20x faster.

Automation: We replace manual processes with VBA or Power Query, which eliminates many performance problems.

First step: Call 010-264 20 20 or email info@exceldepartment.se. We make a quick assessment and give guidance — often it costs nothing.

Summary: Your optimisation plan

Quick fixes (5-15 min): 1. Remove unused rows/columns (Method 5) 2. Save as .xlsb (Method 8) 3. Disable unused add-ins (Method 11)

Medium term (30-60 min): 4. Replace volatile functions (Method 1) 5. Simplify complex formulas (Method 2) 6. Avoid whole-column references (Method 3)

Long term (projects): 7. Convert historical formulas to values (Method 4) 8. Migrate to Power Query (Method 12) 9. Get professional optimisation (Excel Department)

With these methods you can expect Excel to be 50-90% faster for most files.

Related content

• Excel troubleshooting guide — Systematic problem solving
• Common Excel problems — Quick solutions
• Excel automation with VBA — Automate to save time
• Power Query guide — Efficient data import
• Excel help and support — Professional help

Excel Department Slottsbacken 8, Stockholm Phone: +46-10-264-20-20 / 010-264 20 20 Email: info@exceldepartment.se

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