Files stay in your browser
Free CSV tools that process files locally
Inspect and prepare a local CSV without sending its contents to DataOlllo, Vercel, or another processing service. Choose a focused tool, get the result, and continue with the next step.
CSV Row Counter
Count logical CSV records, data rows, physical lines, columns, blank records, and inconsistent row widths.
Count CSV recordsCSV Delimiter Detector
Compare commas, tabs, semicolons, pipes, and colons while checking line endings and encoding clues.
Detect a delimiterLarge CSV Splitter
Create smaller local outputs by data-record count, number of files, or approximate file size.
Split a CSV locallyOne local workflow
Start by counting records and checking file structure. Confirm the detected separator when a destination opens the CSV incorrectly. Then split the source into parts that fit an import limit, review process, or transfer requirement.
No processing backend
The site serves static code. After you choose a file, a browser Web Worker reads local chunks and calculates results on your device. The implementation has no processing API, Vercel function, temporary upload, or cloud result file.
Learn the complete workflow
Large, local, and private CSV guides
Continue from a free utility to a practical guide for opening, filtering, splitting, or analyzing large CSV files on your own computer.
Large CSV viewer
Open, inspect, filter, clean, split, and export oversized CSV files locally.
Read the guideCSV too large for spreadsheet-style tools
Understand common size and memory limits and create a smaller usable output.
Read the guideOpen large CSV locally
Work from local storage without adding an upload-first processing step.
Read the guideSplit a large CSV file
Divide a source by rows, target size, or unique column values.
Read the guideFilter a large CSV file
Select the rows and columns needed from a large local dataset.
Read the guidePrivate CSV analyzer
Inspect sensitive data locally and export only a purpose-specific result.
Read the guideOffline CSV viewer
View and prepare CSV files while keeping the source on your computer.
Read the guideAnalyze CSV without uploading
Inspect, filter, clean, summarize, and export a local CSV without sending the source to a cloud tool.
Read the guideSplit a large CSV by column value
Create separate local outputs for regions, dates, categories, or another meaningful field.
Read the guideView CSV without uploading
Inspect sensitive or large CSV files locally before deciding what to do next.
Read the guideOpen a 20GB CSV file
Use a controlled local workflow for a very large source instead of forcing it into a spreadsheet.
Read the guideMerge large CSV files
Inspect, combine, and validate recurring CSV exports on your computer.
Read the guideCSV file too big to upload
Prepare a smaller, upload-ready result locally while retaining the original source.
Read the guideNeed to open, filter, split, or analyze very large CSV files locally?
Browser tools are convenient for focused checks. For multi-gigabyte sources, advanced filtering, splitting by column values, or repeatable local workflows, download DataOlllo desktop.