The "comma" in CSV is a misnomer — many CSV files use semicolons (common in Europe, where commas are used as decimal separators), tabs, pipes, or even unusual characters like the caret (^). Incorrect delimiter detection causes all data to appear in a single column. HarmonyPal uses a heuristic that counts candidate delimiter characters per line and selects the one with the most consistent count across rows. A custom delimiter option is available for exotic formats.
Free CSV Converter — Online
Convert CSV to Excel, JSON, PDF & Back
Convert CSV files to Excel XLSX, JSON, PDF, or HTML — and convert Excel, TSV, and JSON back to CSV. Perfect for data engineers, analysts, and developers.
CSV to Excel, JSON & PDF
Excel & TSV to CSV
UTF-8 encoding, custom delimiters
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Up to 100 MB free • Outputs: CSV, XLSX, JSON, PDF
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Simple & Fast
How to Use CSV Converter
Convert your files in three simple steps — no software, no signup.
01
Upload Your CSV
Drop a .csv or .tsv file. Auto-detects delimiter (comma, semicolon, tab, pipe) and encoding.
02
Choose Output Format
Select Excel XLSX for spreadsheet editing, JSON for APIs, PDF for reporting, or another delimiter format.
03
Download Converted
Your converted file downloads instantly — headers, data types, and row structure are all preserved.
Features
Why Use CSV Converter?
Auto-Detect Delimiter
We automatically detect comma, semicolon, tab, and pipe delimiters so you don't need to configure anything before converting.
Excel XLSX Output
CSV to XLSX creates a properly formatted Excel workbook with the first row as column headers and correct data types.
JSON Array Output
CSV converts to a JSON array of objects, using the header row as keys — perfect for REST APIs and JavaScript applications.
PDF Table Export
Render your CSV as a paginated PDF table with column headings — ideal for reports, data snapshots, and printed summaries.
HTML Table Export
Convert CSV to an HTML table that you can embed directly in a web page or wiki. Styled with clean Bootstrap-compatible markup.
Private Data Handling
CSV files may contain sensitive business data. All uploads are processed in isolated sessions and deleted within 2 hours.
Compatibility
Supported Formats
All the formats you need, all in one place.
| Format | Description | Extension | Best Used For |
|---|---|---|---|
| CSV → XLSX | CSV to formatted Excel workbook | .xlsx |
Data analysis, pivot tables, charts |
| CSV → JSON | CSV to JSON array of objects | .json |
REST APIs, JavaScript, NoSQL import |
| CSV → PDF | CSV as a paginated PDF table | .pdf |
Data reports, printed summaries |
| CSV → HTML | CSV to an HTML <table> element | .html |
Web embedding, wiki tables |
| CSV → TSV | Comma-separated to tab-separated | .tsv |
Bioinformatics, PostgreSQL COPY |
| XLSX → CSV | Excel spreadsheet to CSV | .csv |
Data export, database import |
| JSON → CSV | JSON array of objects to flat CSV | .csv |
API response to spreadsheet |
| TSV → CSV | Tab-separated to comma-separated | .csv |
Normalise data pipeline input |
FAQ
Frequently Asked Questions
We auto-detect comma (,), semicolon (;), tab (\t), and pipe (|) delimiters. If your file uses a custom delimiter, specify it in the "Custom Delimiter" option field.
Yes — we attempt to infer data types: numeric strings become JSON numbers, "true"/"false" become JSON booleans, and ISO date strings are preserved as strings. Everything else is a JSON string.
Properly quoted multi-line fields (RFC 4180 compliant) are parsed correctly. Fields containing newlines must be enclosed in double quotes.
We detect UTF-8, UTF-8-BOM, UTF-16, Latin-1 (ISO-8859-1), and Windows-1252 encodings automatically. All output files use UTF-8.
By default the first row is treated as column headers. Toggle the "No Header Row" option if your CSV has no header to prevent the first data row from being used as field names.
Files up to 100 MB are supported. Very large CSV files (millions of rows) converting to XLSX are subject to Excel's 1,048,576 row limit — excess rows are truncated.
Real-World Uses
Who Uses CSV Converter?
From everyday users to professionals — see how people rely on this tool every day.
Business Analyst
CSV to Excel for Data Analysis
Convert raw CSV exports from CRMs and databases to XLSX to add pivot tables, charts, and conditional formatting.
Developer
CSV to JSON for REST APIs
Convert a CSV data file to a JSON array of objects for direct use in REST API responses or JavaScript applications.
Data Reporter
CSV to PDF for Printed Reports
Render a CSV dataset as a paginated PDF table — ideal for printed management reports, board packs, or compliance summaries.
Web Developer
CSV to HTML Table for Web Pages
Convert a CSV file to a clean HTML table that can be embedded directly in a web page, wiki, or CMS content block.
Database Admin
Excel to CSV for Database Import
Convert Excel exports to clean UTF-8 CSV for bulk import into PostgreSQL, MySQL, MongoDB, or BigQuery.
Data Engineer
Normalise Delimiter Formats
Convert TSV (tab-separated) or semicolon-delimited files to standard comma-separated CSV for pipeline compatibility.
Why HarmonyPal?
HarmonyPal vs. Alternatives
See how we compare to desktop software and other online converters.
| Feature |
Our Tool HarmonyPal |
Excel | Other Online |
|---|---|---|---|
| CSV → Excel XLSX | |||
| CSV → JSON array | Limited | ||
| CSV → PDF table | |||
| CSV → HTML table | |||
| Auto-detect delimiter (comma, tab, semicolon, pipe) | Partial | Varies | |
| Excel → CSV | |||
| JSON → CSV | |||
| Free to use | Varies |
Under the Hood
Technical Specifications
Built on industry-standard open-source tools for maximum quality and reliability.
Limits & Restrictions
- Max file size: 100 MB (free)
- XLSX output: max 1,048,576 rows (Excel limit)
- Input: CSV, TSV, XLSX, JSON array
CSV
Excel
XLSX
JSON
PDF
HTML
TSV
Data Conversion
Conversion Engine
Custom Python csv/pandas pipeline · LibreOffice Calc (XLSX output) · GhostScript (PDF output)
Output Quality
UTF-8 output with BOM · ISO 8601 dates · type inference for JSON export
Average Speed
Typical: 1–5 s for most CSVs; large files (50 MB+) may take 10–20 s
Data Security
HTTPS transfer · isolated temp dir · auto-purged in 2 h
Input formats
CSV, TSV, XLSX, XLS, JSON
Output formats
XLSX, JSON, PDF, HTML, TSV, CSV
Delimiter detection
Comma, semicolon, tab, pipe — auto-detected
Complete Guide
CSV Conversion In-Depth: Delimiters, Encoding, Data Types, and the Gotchas Every Data Professional Should Know
CSV is the most widely used data interchange format — and also the most misunderstood. Despite its apparent simplicity, delimiter ambiguity, encoding issues, and data type inference make robust CSV handling genuinely challenging.
Delimiter Detection: Why It Matters
Character Encoding and BOM
CSV files can be encoded in UTF-8, UTF-16, Latin-1, or Windows-1252. The wrong encoding causes mojibake — garbled characters where accented letters, currency symbols, or non-Latin scripts should be. We auto-detect encoding using the chardet library and re-encode output as UTF-8. XLSX output includes a UTF-8 BOM (byte order mark) because Excel on Windows requires it to correctly display UTF-8 CSV files when double-clicked — without the BOM, Excel defaults to the system code page.
CSV to JSON: Data Type Inference
When converting CSV to JSON, raw string values need to be mapped to JSON types. We apply type inference: strings that look like integers (e.g. 42) become JSON numbers; strings matching ISO 8601 date patterns (e.g. 2024-03-15) become strings in the JSON (since JSON has no native date type); true and false (case-insensitive) become JSON booleans; empty cells become null. Everything else is a string. Type inference can be disabled via the "String types only" option.
Multi-Line Fields and Quoting Rules
RFC 4180 defines the standard for CSV quoting: fields containing the delimiter, double quotes, or newline characters must be enclosed in double quotes. Double quotes within a field are escaped by doubling them (""). A field containing a newline is valid and results in a multi-line CSV row. Our parser handles all of these edge cases correctly, including files that mix quoted and unquoted fields within the same file.
CSV to PDF: Rendering Tabular Data
To render a CSV as a PDF table, we first load the data into a LibreOffice Calc sheet and then use GhostScript to produce a print-quality PDF. Column widths are auto-sized to the widest value in each column. Headers are bolded. The table is paginated with headers repeated on each page for readability in multi-page reports. Very wide tables (many columns) are rendered in landscape orientation automatically when they would not fit in portrait at a readable font size.