Spreadsheet Converter
Excel to CSV / JSON - Extract and convert data from spreadsheets securely.
Turn complex Excel workbooks into clean, developer-ready CSV or JSON files. Keep your financial models, customer lists, and proprietary data completely offline.
Free trial · No account required · Files stay on your device
All conversions happen locally on your computer. No uploads, no subscriptions, and no background syncing.
Excel → CSV / JSON
Real File Studio interface, shown in light and dark mode.
Why not an online converter?
No uploads, no pop-ups, no sign-up walls
Understanding the CSV format
CSV (Comma-Separated Values) is the simplest tabular data format in widespread use. A CSV file is plain text where each line represents a row and fields are separated by a delimiter, typically a comma. There is no formal owner of the format, but RFC 4180 (published in 2005) describes the most commonly accepted conventions: fields containing the delimiter, quotes, or line breaks must be enclosed in double quotes, and embedded double quotes are escaped by doubling them.
Despite its simplicity, CSV has many real-world variations. European locales often use semicolons as delimiters because the comma is the decimal separator. Some systems use tabs (technically TSV) or pipes. Line endings vary between LF (Unix), CRLF (Windows), and CR (legacy Mac). Character encoding is not declared inside the file, so a CSV must be paired with knowledge of its encoding (UTF-8, UTF-16, Windows-1252, ISO 8859-1) or risk garbled non-ASCII characters.
When converting from Excel to CSV, the rich features of XLSX (formulas, formatting, multiple sheets, merged cells, data types) collapse into flat text. Formulas are replaced with their computed values, formatting is lost, and only one sheet can be exported per file. Numbers with currency or date formats become raw values whose interpretation depends on the receiving program. This trade-off is exactly why CSV remains the lingua franca of data interchange between databases, scripts, and analysis tools.
How it works
Convert Excel to CSV / JSON in four simple steps.
The flow mirrors the main File Studio experience: install the app, drop in your files, pick the right tool, and export clean, ready-to-share output. All without sending anything to the cloud.
Install File Studio
Download the app, move it to Applications, and open it. No sign-ups or accounts required.
Add your Excel files
Drag-and-drop your excel files into the window or click to browse from disk.
Choose Excel → CSV / JSON
Pick the dedicated tool, then adjust resolution, quality, and page range until the preview feels right.
Export & keep working
Select an output folder and run the conversion. Your originals stay untouched on your device.
Best practices for cleaner results
- ·Group related files into folders before converting so your output stays organized and easy to archive.
- ·Use higher resolution presets when you know the result will be printed, zoomed in, or reused in design tools.
- ·Keep an unedited copy of your original Excel files for audits, record-keeping, or compliance workflows.
- ·Combine this tool with other File Studio actions like compress, merge, or split to streamline entire document pipelines.
Why File Studio
Built for trustworthy, everyday Excel to CSV / JSON work.
You get precise control over the output, predictable file names, and a private workflow that keeps sensitive documents on your own machine.
Features tuned for this conversion
- ·Support for XLSX, legacy XLS, and ODS files.
- ·JSON output is an array of row objects keyed by the header row.
- ·Batch convert many spreadsheets at once.
Why use File Studio for this conversion?
- ·Convert Excel to CSV or JSON formats.
- ·Pick which sheet to export.
- ·100% offline - your data never leaves your device.
Real-world ways people use it
- ·Prepare customer data for database imports.
- ·Convert financial reports into machine-readable JSON.
- ·Extract specific worksheets from large Excel files.
Settings guide
Understanding your conversion options
Delimiter
File Studio writes standard comma-separated CSV, the most universally supported variant. If your downstream tool needs tab-separated data, choose TSV as the output instead. Semicolon and pipe delimiters are not offered.
Encoding
Output is UTF-8, which handles any language and is preferred by Unix tools and most programming languages. Note that some older versions of Excel may not detect UTF-8 automatically when double-clicking a CSV; use Excel's import option and choose UTF-8 if accented characters look wrong.
Sheet Selection
An Excel workbook can contain many sheets, but a CSV holds only one. Choose which sheet to export from the Sheet menu, and run the conversion again for each additional sheet you need.
Dates
Excel stores dates as serial numbers internally. File Studio writes them as ISO 8601 text (for example 2026-04-08), which sorts correctly as text and is unambiguous across locales.
Quoting
File Studio follows RFC 4180: double quotes are added only around fields that contain a comma, a quote, or a line break, and embedded quotes are doubled. Formulas are exported as their calculated values.
Industry standards and requirements
Database systems (PostgreSQL, MySQL, SQL Server, Snowflake) all support CSV import via dedicated commands like COPY, LOAD DATA INFILE, and BULK INSERT. Each accepts variations on RFC 4180, with options for delimiter, quote character, header row, and null marker. For high-volume data loading, CSV with proper quoting and consistent encoding is faster than JSON or XML by an order of magnitude because the parser is simpler.
Financial regulators in the U.S. (SEC, CFTC) and Europe (ESMA) accept CSV for transaction reporting under MiFID II, Dodd-Frank, and EMIR. These submissions specify exact column orders, date formats (typically ISO 8601), and decimal separators. Validation tools at the receiving agency reject any file that deviates from the schema, so producers must control encoding, delimiter, and quoting precisely.
Open data initiatives such as data.gov and the European Data Portal require CSV files to follow the W3C CSV on the Web (CSVW) recommendations, which include a JSON schema describing column types, units, and constraints. CSVW enables machine-readable validation while keeping the data file itself in the simplest possible format for direct download and analysis.
Troubleshooting
Common issues and how to fix them
Special characters appear as question marks or boxes→
The CSV is UTF-8, but the program opening it assumed a different encoding. In Excel, import the file through Data > From Text/CSV and choose UTF-8, or open it in a UTF-8-aware editor to confirm the characters are intact.
Numbers with leading zeros lose them after conversion→
CSV does not distinguish text from numbers, so '00123' is interpreted as the number 123 by most spreadsheet importers when the CSV is opened. Import the CSV with that column set to Text, or format the source column as Text in Excel before exporting.
Long numbers are converted to scientific notation→
Excel displays numbers longer than 15 digits in scientific notation by default and may store them with reduced precision. For identifiers, account numbers, and tracking codes, format the source column as Text before populating the cells, or prefix values with an apostrophe to force string storage.
Multi-line cells break the row structure→
Cells containing line breaks are enclosed in quotes per RFC 4180. If the importing tool does not respect quoting, replace embedded line breaks with spaces in the source workbook before export. Verify by opening the CSV in a text editor.
Doing this every week?
Point a File Studio watch folder at a folder and every file dropped in is processed automatically, on that computer. Built for teams that can't upload client files. See how firms use it.
Pricing
Simple, fair pricing.
All tools included. No hidden fees. Processing stays on your device.
Yearly
For short-term projects.
- 1 year of updates
- Image, PDF, SVG, and spreadsheet tools
- Batch processing & Watch Folders
- AI integration (CLI & local MCP)
- Works on Mac & Windows
- All processing done on device
Lifetime
One purchase. Keep it forever.
- Unlimited conversions forever
- 1 year of major updates
- Image, PDF, SVG, and spreadsheet tools
- Watch Folders & Automation
- AI integration (CLI & local MCP)
- macOS Notch Drop Zone
- Works on Mac & Windows
Team & Bulk Pricing
Lifetime seats with volume discounts. More seats, bigger discount.
15
lifetime seats
You save
$60
15% off the individual price
Enterprise
50+ seats with custom pricing, one shared license key, and priority support.
FAQ
Frequently asked questions
Is my spreadsheet data uploaded anywhere?→
No. All data processing and conversion happens locally on your computer. Your sensitive spreadsheets are never sent to the cloud.
Can I convert multiple spreadsheets at once?→
Yes. Batch Processing converts many Excel files to CSV or JSON in a single run.
Does it support multiple worksheets?→
You pick which worksheet to export. CSV, TSV, and JSON outputs contain one sheet per file, so convert again to export another sheet. Only XLSX output keeps every sheet.
Are formulas evaluated during conversion?→
Yes, the converter extracts the calculated values from your formulas rather than the formula text itself.
Can I customize the CSV delimiter?→
CSV output uses commas. If you need tabs instead, choose TSV output. Other custom delimiters are not available.
How large of a spreadsheet can I convert?→
File Studio is optimized for performance and can handle very large datasets, limited primarily by your computer's memory.
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