Excel Price History to Parquet for Research

A price history kept in Excel loads slowly in research code. Parquet fixes that and keeps the column types.

Open the Excel to Parquet converter

Open the Excel to Parquet converter, drop the workbook and turn on type detection. Only the first sheet of an .xlsx file is read, and old .xls files must be saved as .xlsx first.

Parquet keeps a type for every column, so set numbers, dates and text before you export, and read the file back to check it.

Look at the dates before you export. A column with some real dates and some text dates will stay text, so sort by date and check the first and last rows. Run the Data Profiler to count blanks and duplicates.

Everything runs in your browser and nothing is uploaded.

Open the Excel to Parquet converter

Related tool pages

  • JSON, CSV, Parquet and Excel Converter: Convert between JSON, CSV, Parquet and Excel online for free, one file or a whole folder. It runs in your browser, so nothing is uploaded.
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  • CSV to Parquet Converter: Convert CSV to Parquet in seconds. Drop a file or paste data and download the result. Private: it runs in your browser and nothing is uploaded. Large files too.
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How to use the Excel to Parquet converter: step by step

  1. Put the table on the first sheet.
  2. Open the Excel to Parquet converter.
  3. Check dates and prices.
  4. Download Parquet.

When to use the Excel to Parquet converter

  • Speed up loading of a price history
  • Move research from Excel to code
  • Keep types in a shared file
  • Shrink an archive

Example

Input: report.xlsx

Output: report.parquet

Frequently asked questions

Why convert Excel to Parquet?

Parquet is smaller and faster to load in tools like pandas, Spark, DuckDB and BigQuery.

Are numbers and dates kept as types?

Yes. Turn on type detection and numbers, dates and booleans are written as real column types.

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.

Tip: Sort by date and look at both ends. Mixed text and real dates show up there.