Convert Excel to CSV Online — Multi-Sheet, In-Browser

Need a CSV out of an .xlsx file? PondPilot converts Excel to CSV entirely in the browser, with multi-sheet support and SQL filtering before export.

How to Convert

  1. Open app.pondpilot.io
  2. Drop in your .xlsx file
  3. Pick a sheet (or query across sheets)
  4. Export as CSV

The conversion runs locally via DuckDB WebAssembly. Your Excel file never leaves your machine.

Multi-Sheet Workbooks

Real Excel files have more than one sheet — a summary tab, a raw data tab, a notes tab. PondPilot exposes each sheet as a queryable table, so you can pick the one you want or combine them:

SELECT * FROM 'report.xlsx'.Sales
UNION ALL
SELECT * FROM 'report.xlsx'.Refunds;

Export the result as a single clean CSV.

Filter and Clean First

Excel files are messy — merged cells, header rows, trailing totals, blank columns. Convert what you actually need:

SELECT
  TRIM(customer) AS customer,
  TRY_CAST(amount AS DECIMAL(12,2)) AS amount,
  STRPTIME(date_text, '%m/%d/%Y')::DATE AS order_date
FROM 'report.xlsx'.Sales
WHERE customer IS NOT NULL
  AND customer NOT ILIKE '%total%';

Strip out the junk, fix the types, and export a CSV that downstream tools will actually accept.

Why CSV Instead of Parquet?

Sometimes the person on the other end just wants a CSV they can open in their own spreadsheet or import into a legacy tool. CSV is the universal fallback. If you have the choice, Parquet is better — see the Parquet converter.

Privacy

Excel files from finance, HR, and operations almost always contain sensitive data. PondPilot processes everything locally in your browser. No server processes your spreadsheet.

Get Started

Visit app.pondpilot.io and convert your Excel file to CSV.

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