Convert CSV to JSON on Mac, Linux, and Windows — Native Commands + Browser

Every major operating system can convert CSV to JSON natively — Mac and Linux with Python, Windows with PowerShell. Here are the exact commands for each platform, plus the cross-platform browser option that skips the terminal entirely.

Mac / Linux: Python One-Liner

macOS ships with Python 3. Most Linux distributions (Ubuntu, Fedora, Debian, Arch) include it too. Open your terminal and run:

python3 -c "import csv,json,sys; print(json.dumps(list(csv.DictReader(open(sys.argv[1], encoding='utf-8-sig'))), indent=2))" data.csv

This prints formatted JSON directly to your terminal. To save it as a file:

python3 -c "import csv,json,sys; print(json.dumps(list(csv.DictReader(open(sys.argv[1], encoding='utf-8-sig'))), indent=2))" data.csv > output.json

What is happening in that one-liner:

• csv.DictReader reads the CSV, using the first row as keys
• list() converts the lazy reader into a list of dictionaries
• json.dumps(indent=2) formats the list as pretty-printed JSON
• encoding='utf-8-sig' strips the invisible BOM bytes that Excel adds
• sys.argv[1] takes the filename from the command line argument

Windows: PowerShell (Zero Install)

PowerShell ships with every Windows 10 and 11 installation. No Python, no npm, no downloads needed:

Import-Csv data.csv | ConvertTo-Json | Out-File output.json

That is the entire command. PowerShell reads the CSV, converts each row to a PowerShell object, serializes to JSON, and writes the file.

For large files, add depth control and encoding:

Import-Csv data.csv -Encoding UTF8 | ConvertTo-Json -Depth 10 | Out-File output.json -Encoding UTF8

PowerShell gotcha: By default, ConvertTo-Json has a depth limit of 2. If your data is simple (flat CSV), this does not matter. If you are processing complex data, set -Depth 10 to avoid truncation.

All Platforms: Browser Tool (No Terminal, No Install)

If you do not want to open a terminal at all:

1. Open the CSV to JSON Converter in any browser
2. Paste your CSV (or open your .csv file in a text editor, select all, copy, paste)
3. Copy the JSON output
4. Paste into your target application or save as a .json file

Works on Mac, Windows, Linux, ChromeOS, tablets, and phones. No Python version issues, no PATH configuration, no terminal familiarity required.

Platform Comparison

Criteria	Mac/Linux Python	Windows PowerShell	Browser Tool
Pre-installed?	✓ Yes (Mac + most Linux)	✓ Yes (Win 10/11)	✓ Just needs a browser
Speed for small files	✓ Instant	✓ Instant	✓ Instant
Speed for large files	✓ Handles millions of rows	~Slower on 100K+ rows	~Slows at 50K+ rows
Encoding handling	✓ utf-8-sig for BOM	✓ -Encoding UTF8	✓ Automatic
Scriptable / automatable	✓ Cron, bash scripts	✓ Task Scheduler	✗ Manual process
Learning curve	~Need terminal basics	~Need PowerShell basics	✓ None — paste and copy
Custom delimiters	✓ delimiter parameter	✓ -Delimiter parameter	✓ Dropdown or auto-detect
Data stays local	✓ Yes	✓ Yes	✓ Yes (no upload)

Advanced: Making It a Reusable Command

Mac/Linux — add to your shell profile:

# Add to ~/.bashrc or ~/.zshrc
csv2json() { python3 -c "import csv,json,sys; print(json.dumps(list(csv.DictReader(open(sys.argv[1], encoding='utf-8-sig'))), indent=2))" "$1"; }

Then convert any file with: csv2json data.csv > output.json

Windows — create a PowerShell function:

# Add to your PowerShell profile
function csv2json { param($f) Import-Csv $f -Encoding UTF8 | ConvertTo-Json -Depth 10 }

Then: csv2json data.csv | Out-File output.json

Platform-Specific Gotchas

Platform	Gotcha	Fix
Mac	python vs python3 — macOS may have Python 2 as default	Always use python3 explicitly
Ubuntu 24+	Python may not be pre-installed on minimal installs	sudo apt install python3
Windows	PowerShell execution policy may block scripts	Run Set-ExecutionPolicy RemoteSigned in admin terminal
Windows	ConvertTo-Json wraps single-row CSV in object, not array	Pipe through @() to force array: @(Import-Csv file) | ConvertTo-Json
All	CSV from Excel has invisible BOM bytes	Python: utf-8-sig encoding. PowerShell: -Encoding UTF8.
All	European CSV uses semicolons, not commas	Python: delimiter=";" — PowerShell: -Delimiter ";"

Complete Data Toolkit

• CSV to JSON Converter — browser-based, works on every platform
• JSON to CSV Converter — reverse direction when teammates need spreadsheets
• JSON Formatter — validate and pretty-print your converted output
• CSV Sanitizer — clean data before converting
• TSV to CSV — convert tab-separated data to CSV first if needed
• Split Spreadsheet — break large files into chunks before processing
• Excel to CSV — export .xlsx to .csv before JSON conversion