Convert a Large CSV to Parquet

Convert a CSV of 500 MB or more to Parquet in your browser. Smaller files, faster queries and no upload.

Quick answer: Convert JSON, CSV, Parquet and Excel – one file or a whole folder.

Related: JSON, CSV, Parquet and Excel Converter · JSON to CSV Converter · CSV to JSON Converter · CSV to Parquet Converter · Parquet Guides and Free Parquet Tools

How to use the Convert a Large CSV to Parquet

Convert JSON, CSV, Parquet and Excel – one file or a whole folder.

The Format Converter moves data between JSON, CSV, Parquet and Excel without code or an install. It reads your file in the browser, flattens nested JSON into columns, keeps or guesses column types, and writes the format you choose. Use it to open API data in Excel, load a spreadsheet into an app, shrink a big CSV into Parquet, or look inside a Parquet file. Nothing is uploaded, so it is safe for customer and business data.

  1. Pick From and To
  2. Drop or paste your data
  3. Convert and download

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Example

Input: events.csv (500 MB)

Output: events.parquet

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Who uses Data Utility

Frequently asked questions · Data format benchmark

Frequently asked questions

How much smaller is Parquet?

Usually 5 to 10 times smaller than CSV, depending on your data.

How big can a file be?

It depends on your device. A few hundred MB usually works.

Which conversions does the Format Converter support?

Any direction between JSON, CSV, Parquet and Excel (.xlsx), for one file or a whole folder. Nested JSON is flattened into columns such as address.city. For Excel, the first sheet is read; old .xls files are not supported.

Why did my number or date change after converting?

Types are detected from the values. Turn off "Detect types" to keep everything as text, which also keeps leading zeros in IDs and phone numbers.

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