What quoting dialect does the converter support?

RFC 4180 — the standard CSV spec. Fields containing commas, quotes, or newlines should be wrapped in double quotes, with embedded quotes escaped as two quote characters.

Does the first row become object keys?

Yes. The first row of your CSV is treated as headers; every subsequent row becomes an object with those headers as keys. Uncheck 'first row is headers' to get an array of arrays instead.

Can it handle large CSV files?

Up to about 5 MB comfortably. Larger files may slow your browser since parsing happens client-side. For multi-GB files, use a desktop tool or a streaming parser like PapaParse.

Is my CSV sent to a server?

No. Parsing happens entirely in your browser — nothing you paste leaves the tab.

How does the converter handle missing values?

Empty fields in CSV become empty strings in the JSON output by default. Toggle the 'treat empty as null' option to convert them to JSON null instead. Some CSVs use 'NULL', 'N/A', or '-' as missing-value markers — those convert to literal strings unless you preprocess. For numeric fields where empty should mean 'no data,' null is preferable to empty string for downstream consumers (avoids 'NaN' from Number('')).

Can it auto-detect data types (numbers, booleans)?

Yes — toggle the 'auto-detect types' option. The parser will convert numeric strings ('123' → 123), boolean-like strings ('true', 'false' → true, false), and 'null' literals → null. Off by default to preserve original CSV-as-text fidelity, since some seemingly-numeric values are actually IDs that shouldn't be converted (zip codes 02134 would lose the leading zero if treated as numbers). Toggle on for clean numerical / categorical data; off for raw text imports.

File & Format Converters · Free tool

CSV to JSON

Convert your CSV data into clean, well-formatted JSON instantly. This free tool handles quoted fields and custom delimiters, no upload required.

Updated June 2026

DelimiterFirst row is headerPretty print

CSV input

JSON output (3 rows)

[
  {
    "name": "Ada",
    "age": "36",
    "city": "London"
  },
  {
    "name": "Alan",
    "age": "41",
    "city": "Manchester"
  },
  {
    "name": "Grace",
    "age": "79",
    "city": "New York"
  }
]

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What it does

A free CSV to JSON converter that runs entirely in your browser. Paste CSV, pick the delimiter (comma, semicolon, tab, or pipe), and get a JSON array of objects — with the first row as keys by default. Handles quoted fields with embedded commas, escaped quotes, and both Unix and Windows line endings.

CSV is the universal data language everyone exports but no one enjoys parsing. JSON is what every API speaks. Going between them is a constant chore — this tool makes it a paste-and-copy in three seconds. For the opposite direction, see our JSON to CSV converter.

Embed this tool on your siteShow snippet

Paste this snippet into any page. Loads on-demand (lazy), no tracking scripts, and sized to most dashboards. Replace the height to fit your layout.

<iframe src="https://freetoolarena.com/embed/csv-to-json" width="100%" height="720" frameborder="0" loading="lazy" title="CSV to JSON" style="border:1px solid #e2e8f0;border-radius:12px;max-width:720px;"></iframe>

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How to use it

Paste your CSV into the input box.
Pick the delimiter if it's not a comma.
Toggle 'First row is header' if your CSV doesn't have one.
Copy the JSON output or paste it straight into your code.

When to use this tool

Quickly building test JSON fixtures from spreadsheet data.
Importing CSV data into a JSON-first API or NoSQL database.
Migrating legacy CSV exports into a modern web app expecting JSON.
Sharing tabular data with a developer who prefers JSON over CSV.

When not to use it

Very large CSVs (50MB+) — browser performance degrades; use a streaming parser instead.
CSV with inconsistent column counts per row — JSON requires consistent schema.
Binary or BLOB-containing CSVs — those need specialized handling.

Common use cases

Converting an Excel-exported product catalog CSV to JSON for headless CMS upload.
Migrating a 5,000-row contact list from CSV to JSON for API import.
Building seed data for a development database from a spreadsheet template.
Quickly inspecting CSV fields by converting to JSON and using a JSON viewer.

Frequently asked questions

What quoting dialect does the converter support?: RFC 4180 — the standard CSV spec. Fields containing commas, quotes, or newlines should be wrapped in double quotes, with embedded quotes escaped as two quote characters.
Does the first row become object keys?: Yes. The first row of your CSV is treated as headers; every subsequent row becomes an object with those headers as keys. Uncheck 'first row is headers' to get an array of arrays instead.
Can it handle large CSV files?: Up to about 5 MB comfortably. Larger files may slow your browser since parsing happens client-side. For multi-GB files, use a desktop tool or a streaming parser like PapaParse.
Is my CSV sent to a server?: No. Parsing happens entirely in your browser — nothing you paste leaves the tab.
How does the converter handle missing values?: Empty fields in CSV become empty strings in the JSON output by default. Toggle the 'treat empty as null' option to convert them to JSON null instead. Some CSVs use 'NULL', 'N/A', or '-' as missing-value markers — those convert to literal strings unless you preprocess. For numeric fields where empty should mean 'no data,' null is preferable to empty string for downstream consumers (avoids 'NaN' from Number('')).
Can it auto-detect data types (numbers, booleans)?: Yes — toggle the 'auto-detect types' option. The parser will convert numeric strings ('123' → 123), boolean-like strings ('true', 'false' → true, false), and 'null' literals → null. Off by default to preserve original CSV-as-text fidelity, since some seemingly-numeric values are actually IDs that shouldn't be converted (zip codes 02134 would lose the leading zero if treated as numbers). Toggle on for clean numerical / categorical data; off for raw text imports.

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