Preview first
Open the dataset and inspect columns, row samples, and structure before deciding how to clean or transform it.
10 million row CSV
Open a 10 million row CSV without uploading it
DataOlllo gives analysts a local desktop workflow for very large CSV files, from quick previews to filtering, cleanup, splitting, and summaries.
Filter at scale
Narrow millions of rows by column values, ranges, and text patterns so you can focus on the records that matter.
Export only what matters
Create smaller CSV outputs from selected rows or columns for reporting, review, sharing, or downstream processing.
Common questions
Can I open a 10 million row CSV on a laptop?
Yes, with the right local workflow. DataOlllo is designed for large datasets that are uncomfortable in general-purpose spreadsheet-style tools.
Do I need to write code?
No. DataOlllo provides visual tools for opening, filtering, merging, splitting, and summarizing large files.
Explore the local CSV workflow
Related CSV Tools and Guides
Use a free browser utility for a focused check, or continue with a guide for opening, filtering, splitting, and analyzing large CSV files locally.
Free CSV tools
Count rows, detect delimiters, and split CSV files with browser-only utilities.
View the CSV tools hubOpen a huge CSV file
Learn a practical local workflow for CSV files with millions of records.
Read moreLarge CSV viewer
Preview and reduce large datasets before sending results downstream.
Read moreFilter a large CSV file
Select only the rows and columns needed from a multi-million-row source.
Read moreCSV row count estimator
Verify the exact record count without uploading the CSV.
Read moreCSV delimiter detector
Check the file separator and expected column structure locally.
Read moreWork with very large CSV files on your computer
Open, filter, split, clean, and analyze large or sensitive CSV files locally with DataOlllo desktop.