How to Convert CSV to JSON Free Online (With Real Examples)

What the conversion produces

A CSV like this:

name,email,age,active
John Doe,john@example.com,30,true
Jane Smith,jane@example.com,25,false

Becomes a JSON array of objects, one per row, using the header row as property names:

[
  {
    "name": "John Doe",
    "email": "john@example.com",
    "age": "30",
    "active": "true"
  },
  {
    "name": "Jane Smith",
    "email": "jane@example.com",
    "age": "25",
    "active": "false"
  }
]

Notice: all values are strings by default. CSV has no type system — everything is text. If you need age as a number and activeas a boolean, you'll need to handle type coercion after conversion.

Convert any CSV file using the free CSV to JSON converter — paste CSV or upload a file, get formatted JSON instantly.

Handling the common problems

Commas inside field values

RFC 4180 (the CSV standard) handles commas inside field values by wrapping the field in double quotes:

name,address,city
John,"123 Main St, Apt 4B",Springfield

The addressfield contains a comma but is correctly parsed as one value because it's quoted. Any proper CSV parser handles this — but if you're writing a simple split-on-comma parser yourself, you'll miss this and get the wrong result. Use the converter or a proper library.

Quotes inside quoted fields

name,bio
John,"He said ""hello"" to everyone"

Double-quote characters inside a quoted field are escaped by doubling them (""). The resulting JSON:

{"name": "John", "bio": "He said "hello" to everyone"}

Different delimiters (TSV, semicolons)

Not all "CSV" files use commas. European locales often export with semicolons (;) because commas are used as decimal separators. Tab-separated values (TSV) use tabs.

The converter lets you specify the delimiter — choose comma, semicolon, tab, or pipe (|) depending on your source file.

Type conversion after parsing

Since CSV values are all strings, you'll often need to convert types in code. In JavaScript:

const raw = [
  { name: "John", age: "30", active: "true" }
];

const typed = raw.map(row => ({
  ...row,
  age: Number(row.age),
  active: row.active === 'true'
}));
// Result: { name: "John", age: 30, active: true }

For large datasets, consider using a library like Papa Parse (browser) or fast-csv (Node.js) which supports type inference options.

Converting in code (no tool needed)

If you need to convert CSV to JSON programmatically:

JavaScript (browser/Node.js, simple case):

function csvToJson(csv) {
  const lines = csv.trim().split('\n');
  const headers = lines[0].split(',');
  return lines.slice(1).map(line => {
    const values = line.split(',');
    return headers.reduce((obj, header, i) => {
      obj[header.trim()] = values[i]?.trim() ?? '';
      return obj;
    }, {});
  });
}

Note: this simple approach doesn't handle quoted fields with commas inside them. For production use, use Papa Parse or a proper CSV library.

Python:

import csv, json

with open('data.csv', newline='') as f:
    reader = csv.DictReader(f)
    data = list(reader)

print(json.dumps(data, indent=2))

Common use cases

• Google Sheets → API payload: Export as CSV → convert to JSON → POST to a REST API that expects JSON
• Excel data → database seed: Convert CSV export to JSON for seeding a database via a script
• Product catalog import: Many e-commerce platforms accept JSON imports — convert your spreadsheet product data
• Data analysis prototype: Convert CSV data to JSON to use with JavaScript charting libraries (Chart.js, D3.js) that expect JSON arrays

Related tools

• Free CSV to JSON Converter — convert CSV files or paste CSV text to JSON instantly
• Free JSON Formatter — format and validate the resulting JSON

Written by Achraf A., founder of TheFreeAITools.