Google Sheets: How to Use FLATTEN + INDEX Together (2025)

2/10/2025

Google Sheets: How to Use FLATTEN + INDEX Together (2025)

To use FLATTEN + INDEX in Google Sheets, combine them inside a LET() block and reference the array directly. This removes the need for helper columns and massively improves performance.

Quick Fix

  • Combine into a single array using LET()
  • Remove helper columns
  • Use INDEX/SEQUENCE to structure the output

Full Steps

  1. Step-by-step instructions…

Why This Happens

Technical explanation…

Extra Tips

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FAQ

Why does this formula lag?
Explanation…

Conclusion

Short wrap-up here.