Free online Excel converter for XLSX, XLS, CSV, TSV, ODS and more. Add a spreadsheet, select CSV, TSV, XLSX, XLS, ODS, JSON or HTML, press Convert and download the file.
Spreadsheet format work by OnlinePCApps since 2013
A spreadsheet in the wrong format will not import, will not load into an app or will not open in another program. The free online Excel converter puts the data in the format the job needs.
Databases, ETL pipelines and most import screens expect CSV, not XLSX. Converting a workbook to CSV with the online Excel converter strips the Excel layer and leaves plain rows that load into Postgres, MySQL, a CRM or an analytics tool without a hitch.
An app, an API or a test needs structured data, not a workbook. Converting to JSON with the Excel converter online maps the header row to keys and every row to a record, ready to drop into a request, a seed script or a JavaScript file.
A payroll sheet, a client list or a budget should not sit on an outside server for a format change. SheetJS runs in the browser, so the workbook stays on the device while it converts.
Drag the workbook onto the online Excel converter, or select Open spreadsheet file to browse for it. The panel takes .xlsx, .xls, .csv, .tsv, .ods, .xlsm, .xlsb, .xml and .html files up to 100 MB, one file per run.
A Target Export Format row appears with CSV, TSV, XLSX, XLS, ODS, JSON and HTML. CSV is selected first, and the main button names the choice, like Convert to CSV.
Press the button, then select Download Converted File. It saves as the original name plus -converted and the new extension. A JSON result also opens as Parsed JSON Output before download, and Convert Another clears the panel.
To convert a spreadsheet is to rewrite the same data in a different format. The online Excel converter does that for nine input types and seven output formats.
The same data is rewritten from one format into another, from XLSX to CSV, CSV to XLSX, XLSX to JSON and the rest. The input format is detected on its own, so only the output has to be chosen.
The panel converts the primary worksheet and has no sheet picker. A CSV or a TSV holds one sheet anyway. To convert another tab, save it as its own file and run it through the online Excel converter again.
Converting to JSON opens a Parsed JSON Output box, so the records can be checked before download. Every row becomes a record keyed by the first row, ready for an API or a script.
Excel date serials are written as ISO 8601, so a date reads as 2026-01-31 rather than a raw number. A CSV follows the RFC 4180 rules, wrapping any field that holds a comma or a line break in quotes.
To convert a spreadsheet, to turn an XLSX into CSV and to export Excel as JSON all name one task. A search for Excel converter or spreadsheet converter reaches the online Excel converter above.
The file decides what the online Excel converter returns. The cases below run from clean to not on this page.
| The case | Result | What happens and why |
|---|---|---|
| XLSX and CSV | clean | Excel workbooks and CSV convert between one another, the core of the online Excel converter. For why a CSV can still import badly, see Why CSV files break and what they never tell you. |
| XLS, XLSB, XLSM | read as input | Older, binary and macro-enabled Excel files are accepted by the Excel converter online, XLSB being one that few tools besides Excel open. |
| Password protected | unlock first | A workbook locked with a password is opened and saved without it before converting. |
| ODS | OpenDocument | The Excel converter online handles a genuine LibreOffice ODS in and out, not a renamed CSV. |
| JSON | header keys | The first row maps to keys. A Parsed JSON Output box shows the result before download. |
| Multiple sheets | primary sheet | The panel converts the primary worksheet and has no sheet picker. A CSV or TSV holds one sheet anyway. |
| Formulas | values to CSV | A CSV or JSON from the Excel converter online keeps the computed values, while XLSX and ODS can carry formulas. |
| Formatting | not in CSV | Colors, fonts and charts do not survive a move to CSV, JSON or TSV. |
| Dates | ISO 8601 | Excel date serials are written as a plain date like 2026-01-31. |
| Source file | 9 types | Upload takes .xlsx, .xls, .csv, .tsv, .ods, .xlsm, .xlsb, .xml and .html. For a CSV with broken characters, see Character encoding explained and why text arrives broken. |
| File size | 100 MB | A larger file is rejected before conversion. For a bigger workbook, the desktop edition is the better fit. |
| Files per run | one | The panel takes one file at a time. Convert Another clears it for the next file. |
| Output name | -converted | The file saves as the original name plus -converted and the new extension. |
| Where it runs | on the device | The data is rewritten in the browser, so the workbook is not uploaded. |
Workbooks, Sheets and Plain Data
A spreadsheet format decides how much lives in the file beyond the raw numbers. XLSX, the modern Excel format, is a rich container that holds several sheets, formulas, colors, fonts and charts. CSV is the opposite, plain text with one value per cell, one row per line and nothing else. This gap sets the honest rules of a conversion. Moving XLSX to CSV keeps the values of a single sheet and drops the formulas, the formatting and the extra tabs, which is why CSV loads into a database or a pipeline that an XLSX would choke. Moving the other way, CSV to XLSX or to ODS, wraps the same rows in a workbook that Excel and LibreOffice open natively. Formulas survive a move to another spreadsheet format like XLSX or ODS, while a CSV or a JSON keeps the computed value alone. Dates come across as ISO 8601, and a CSV follows the RFC 4180 rules for quoting. The online Excel converter applies these rules to every run. The references below define the formats.
Both the online Excel converter and a hosted one convert a spreadsheet's format. The trade is real, and business data is often sensitive.
| Point of comparison | This tool This online converter On the device | Hosted converter Uploaded and converted on a server |
|---|---|---|
| Where the data goes | Stays on the device | Uploaded to a server |
| Price and caps | Free with no sign-up | Free tier often capped |
| Millions of rows | Capped at 100 MB a file | Reads straight from disk |
| Keep formulas and charts | Data and formulas to a sheet | Excel keeps charts and macros |
| Hundreds of files | One file per run | Batch on their hardware |
The last three rows favor a desktop program, since millions of rows, live formulas and charts or a run of many files all call for more than one browser tab. For an everyday workbook the first two rows count most. The online Excel converter is free with a 100 MB cap per file, and Online file tools and whether yours uploads goes deeper on where a file goes.
The workbook is read and rewritten inside the browser by SheetJS, so the work is client-side and the data stays on the machine that opened it. No copy is passed to a server for the job.
A spreadsheet can be a private thing, a payroll run, a client list or a budget never meant to sit on an outside server. A hosted converter has to upload the entire file to convert it, far more exposure than a format swap is worth.
All of these work as an Excel converter. They differ on effort, on cost and on where the file goes.
Excel, LibreOffice and the command line convert well but need an install or a terminal. Google Sheets needs an account. The online Excel converter above needs a browser and adds JSON output.
Three pointers lead to a cleaner result from the online Excel converter.
CSV suits a database or an import screen. JSON suits an app or an API. XLSX or ODS suits a person who will open and edit the sheet, and the destination usually points to one. The Excel converter online offers all three.
Moving to CSV keeps the values of one sheet and drops formulas, colors, charts and the other tabs. To hold onto those, convert to XLSX or ODS rather than CSV or JSON.
A workbook with several tabs converts one sheet, the primary worksheet. The panel has no sheet picker, so save the tab that holds the data as its own file first.
The online Excel converter takes one file per run, up to 100 MB. A sheet of millions of rows, or a folder of files to convert together, belongs on the desktop edition, which works from disk and converts the entire set in one pass.
Point it at a folder of workbooks and every file is rewritten to the target format in a single run, saved beside the original.
A sheet with hundreds of thousands or millions of rows works from disk, past the 100 MB cap of the online Excel converter.
Saved presets set the output format, the sheet rule and the date handling in one click, ready for a repeated workflow.
No sign-up and no cost. Add a spreadsheet to the online Excel converter, select a format and download the converted file.