03 — 9 tools
Spreadsheet and data tools, offline
Convert between CSV, Excel and JSON. Merge, split, dedupe and inspect tabular data without handing your records to a third party.
- Free forever
- Nothing uploads
- No signup
- No watermark
CSV to Excel
Open full tool →Comma, semicolon or tab separated
All file & data tools
Each tool has its own page, with the settings that matter and an explanation of what it actually does to your file.
CSV to Excel
Get a real .xlsx file with auto-sized columns, without Excel mangling your data on the way in.
Excel to CSV
Pick a sheet from the workbook, preview it, and export a clean UTF-8 CSV.
CSV to JSON
Each row becomes an object keyed by the header row. Values are kept as strings — no silent type guessing.
JSON to CSV
Paste or drop JSON. Nested objects flatten into dotted columns; arrays join with semicolons.
Merge CSV Files
Stack multiple CSVs into a single file. Tell the tool what to do when the headers do not match.
Split CSV
Chunk by row count for upload limits, or split by a column so each value gets its own file.
Remove Duplicate Rows
Untick the columns that should not count towards matching. Keeps the first occurrence of each duplicate.
CSV Viewer
Open a CSV or Excel file, search across every column, and see exactly what is in the cells.
CSV to SQL
Generate INSERT statements, optionally preceded by a CREATE TABLE with inferred column types.
Why browser-based tools
Every other free file & data site works the same way: you upload a file, a server processes it, and you download the result. The upload is the product. Your document sits on someone else's machine, subject to their retention policy, their security, and their commercial interest in what you sent.
The tools on this page never make that request. They use the same JavaScript and WebAssembly libraries a server would run, executed in the tab you already have open. There is no upload endpoint, because there is no server doing the work. You can confirm it: open your browser's network panel, process a file, and watch nothing leave.
The trade is real. Browser processing is bounded by your device's memory, so a two-gigabyte file will fail here and succeed on a server. Some operations — high-quality background removal, OCR, video transcoding — need more compute than a tab reasonably has. Where that is true, this site says so rather than shipping a bad version.