Resources

Guides, reference, and videos for merging messy spreadsheets.

Guides

How to Merge Two Large Spreadsheets by a Shared Column (No VLOOKUP, No Formulas)

Merge two large spreadsheets by a shared column in minutes using AI. Upload both files, review the match plan, refine the list in plain English, then export to Excel.

September 29, 2026 · 12 min read

Reference

TenMil facts

Limits, formats, matching rules, data handling, and pricing in one place.

Phrasebook

Plain-English phrases that work in TenMil's chat, with exact results.

What TenMil won't do

The requests TenMil declines, and what to do instead.

Videos

How to combine two large spreadsheets with AI by matching on a column.

Research

Stress Testing Excel Copilot: Merging Two 700K-Row Excel Files

I asked Excel Copilot to merge two CRM exports totaling 1.47M rows, 15 times. It returned the correct 755,435-contact list in only 4 runs.

October 6, 2026 · 14 min read