As of 13 August 2026, AI can merge data from multiple spreadsheets.

What to actually do

1. Hand it to a person

   The route this page recommends

   A person who owns the outcome does this end to end, worth it when the failure is dear.

2. Use a tool built for this

   Second choice

3. Do it yourself

   The distant third

   A chat interface, chat-fluent skill, and roughly 30 minutes until you can act on the result.

   How to actually do it

   1. Open a working folder and copy in the original spreadsheets without editing them.
   2. Inspect the headers and record the intended matching column, such as customer ID, order number or email address, plus the rows and columns you need in the final file.
   3. Remove passwords or access restrictions from copies only, then upload the copies and paste the prompt into an AI tool that can work with spreadsheet files.
   4. Fill in the bracketed requirements in the prompt and ask the tool to create the merged workbook and its audit report.
   5. Compare the audit report's source and output row counts, unmatched records, duplicate keys and conflict list with the original spreadsheets.
   6. Open the merged workbook with a colleague, check samples from each source sheet and reconcile important totals before saving a versioned final copy or sending it to the report owner.

   Prompt

   Merge the attached spreadsheets into one output workbook.
   
   Before changing anything:
   1. List each file and sheet, including its row count, column names and apparent data types.
   2. Identify possible matching keys and explain which columns you would use to match records.
   3. Do not invent a matching rule. If a match is ambiguous, keep the record unmatched and list it in an exceptions sheet.
   
   Then create the merged output using these requirements:
   - Source files: [file names or descriptions]
   - Desired output: [one row per customer, transaction, case or other unit]
   - Matching key: [column or combination of columns, if known]
   - Columns to retain: [list, or say retain all]
   - Conflict rule when values differ: [rule, or flag the conflict]
   - Duplicate rule: [rule, or retain and flag duplicates]
   - Required output format: [XLSX or CSV]
   
   Preserve the original values and source file or sheet for every output row. Do not silently drop rows, overwrite conflicting values or guess missing data. Produce the merged file if you can. Also produce an audit report containing source row counts, output row count, matched rows, unmatched rows, duplicate keys, conflicting values and any assumptions. If you cannot return a file, provide reproducible Python or spreadsheet steps that perform the merge and explain where I should insert the file names. Finish with a short list of checks I must carry out before using the result.

   Open it prefilled in ChatGPT or Claude, or copy it into Gemini, which takes no prefill link.