Can AI clean up a messy spreadsheet?

Yes — AI can help you clean data in Excel, but it drafts the cleanup rather than finishing it. A general assistant can read an uploaded CSV or spreadsheet, tell you what is wrong with it, and write the formulas, Power Query steps or menu paths you need; you still apply them to a copy and check the result. Every major tool says the same thing about its own output: OpenAI warns ChatGPT can produce incorrect or misleading outputs, Anthropic says not to rely on Claude as a single source of truth, and Microsoft says Copilot can make mistakes and misinterpret information. Treat the assistant as a fast first draft, not as a spreadsheet you can trust unread.

Tools that work

ChatGPT. The Free plan includes unlimited text chats with limited messages that include uploads, so you can attach a file and ask about it. File uploads are capped at about 50MB for CSV or spreadsheet files, with a 512MB per-file ceiling overall; Free users get 3 file uploads per day, and users generally up to 80 files every 3 hours. ChatGPT Plus costs $20 per month, billed monthly; Go is the lower-cost paid tier with higher limits than Free for file uploads and data analysis — its price was not shown on the pricing page when checked, so check the current plan on OpenAI's site. If the data is sensitive, turn off "Improve the model for everyone" under Settings > Data controls before you start; OpenAI says new conversations then won't be used to train its models.

Claude. The Free plan is $0 and includes chat on web, desktop and mobile, web search, file creation and code execution, memory and Artifacts; Pro is $17 per month with the annual discount ($200 billed up front) or $20 if billed monthly. For cleanup work the useful detail is file support: Claude accepts CSV and XLSX (XLSX needs code execution enabled), up to 500MB per file and up to 20 files per chat.

Microsoft Copilot. This is the one that sits inside Excel. Microsoft offers a limited free version of Copilot, subject to available capacity and limits; Microsoft 365 Personal ($9.99/month) and Family ($12.99/month) include Copilot in Word, Excel, PowerPoint and Outlook with higher usage than free, and Premium is $19.99/month. Note that in the Family plan the AI features are for the subscription owner only. Copilot in Excel can edit the workbook directly, and Microsoft says you can undo changes or view prior versions if you need to revert.

Is the free tier usually enough? For occasional cleanup of a modest file, generally yes — the free plans do accept spreadsheet files, and the work is mostly one conversation. You are more likely to hit upload limits or daily caps than to hit a missing feature, which is what the paid tiers raise. Plans and prices change, so check the current plan on the tool's site before you pay.

A prompt to paste

You are helping me clean a spreadsheet. The attached file is [file name].
Each row is [what one row represents, e.g. one customer order from our shop].
The columns are: [column names, and what each one should contain].

Do not change my original file. Give me a cleanup plan I can apply myself in Excel:

1. List every problem you can see in the data: duplicate rows, numbers or dates
   stored as text, extra spaces, non-breaking spaces (character 160),
   non-printable characters, blank or inconsistent entries, mixed date formats,
   and columns that should be split into two.

2. For each problem, give the exact Excel fix - the formula, the Power Query step,
   or the menu path - and say which column and which range it applies to,
   using my real column names.

3. Flag anything you are unsure about, and anything that would change what the
   data means. Do not guess: tell me what I need to check instead.

4. Finish with three checks I can run to confirm the row count and the column
   totals still match the original file.

Two follow-ups that usually pay off:

Rewrite step 2 as a Power Query sequence I can follow in order, keeping the
original source unchanged.

Turn the checks in step 4 into actual Excel formulas I can paste below the data,
using my column names.

How far AI gets you

AI drafts, you finish. The assistant is good at finding what is wrong and writing the fix, but the fix acts on real data and the destructive steps are permanent: Excel's Remove Duplicates deletes duplicate data permanently, and the tools themselves warn they can be wrong while sounding confident. That combination puts the last mile with you.

What you still do

Copy the file first. Microsoft recommends moving or copying the original data to another worksheet before removing duplicates. Keep that copy until you have checked the result.
Look before you delete. Use conditional formatting to highlight duplicates so you can review them and decide whether to remove them.
Know what TRIM does not do. TRIM removes extra spaces except single spaces between words, but does not remove the non-breaking space (character 160). CLEAN removes non-printable characters (ASCII 0–31) from imported text, and the two combine as =TRIM(CLEAN(B5)).
Split stubborn columns. The Convert Text to Columns wizard (Data > Text to Columns) splits one column into several using a delimiter such as a comma or space.
Prefer a repeatable path. Power Query (Get & Transform) lets you remove columns, change data types and filter rows while the original source remains unchanged, and you can refresh it later. That matters if the same messy export arrives every month.
Keep a way back. In Excel, version history only works for files stored in OneDrive or SharePoint, and personal Microsoft accounts can retrieve the last 25 versions. In Google Sheets you can open version history and copy an earlier version, or name up to 15 versions per spreadsheet.
Use an official source or a qualified person when the numbers carry consequences. Payroll, tax figures, insurance claims, medical records, regulated reports and anything you will sign off to a third party should be checked against the official source or by a licensed professional, not by a chat answer. Google's own guidance on Gemini is to double-check responses and not rely on them for professional advice.

Common questions

Can AI remove duplicates for me?

It can write the plan and the steps, and Copilot in Excel can edit the workbook directly, but removal itself is permanent — so review highlighted duplicates first and keep a copy of the original.

Why didn't TRIM fix my spaces?

Because the character is probably a non-breaking space (character 160), which TRIM does not remove; it is common in data copied from web pages. Google Sheets has the same gap: its Data > Data cleanup > Trim whitespace also does not remove non-breaking spaces.

Do I need a paid plan just to clean one spreadsheet?

Usually not. The free tiers of ChatGPT, Claude and Copilot all accept files, with lower limits; paid plans mainly raise those limits and, in Copilot's case, put the assistant inside Excel itself.

Sources