Free Online Data Tools
A collection of free browser-based tools for data scientists and analysts: convert CSV to JSON, format and validate JSON, compute descriptive statistics, visualize datasets, analyze text and clean data. Everything runs locally in your browser - nothing is uploaded to any server.
CSV / JSON Converter
Convert CSV data to JSON and back. Supports custom delimiters, header rows and nested output. Everything runs in your browser.
Open toolJSON Formatter & Validator
Pretty-print, minify and validate JSON with precise error positions. Ideal for cleaning up API responses and config files.
Open toolStatistics Calculator
Paste a column of numbers to get mean, median, mode, standard deviation, variance, quartiles, min/max and outlier hints instantly.
Open toolData Visualizer
Paste CSV or JSON data to explore every column: numeric summaries, category counts and interactive charts. No upload required.
Open toolText Analyzer
Count words, characters, sentences and reading time; extract keyword frequency to prepare text datasets for NLP tasks.
Open toolData Cleaner
Deduplicate lines, trim whitespace, sort, filter and find-and-replace. Quick cleanups for lists and dataset columns.
Open toolFree Online Data Tools for Data Scientists
These tools were built to complement the datasets on this platform. Instead of installing Python libraries or uploading sensitive files to unknown websites, you can convert CSV to JSON, compute statistics, draw charts and clean up lists directly in your browser. All processing happens on your own device using JavaScript, which means your data stays private and the tools work even on large files.
Each tool is designed to work well with the datasets offered on Jizhi Datasets: paste a downloaded CSV into the Data Visualizer to explore it, use the Statistics Calculator to check column distributions, or use the Data Cleaner to deduplicate keyword lists before building NLP training sets.
All Tools
Frequently Asked Questions
Are these online data tools really free?
Yes. All tools on Jizhi Datasets are completely free with no sign-up, no watermarks and no usage limits. They are maintained by our team as a companion to our free dataset library.
Is my data safe when I use these tools?
Yes. Every tool runs entirely in your browser using JavaScript. Nothing you paste or type is ever uploaded to our servers or any third party, so your data never leaves your device.
Do the tools work offline?
Once a tool page is loaded, all calculations happen locally, so they keep working even if you go offline. You only need a connection to load the page initially.