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CSV to JSON Converter — Free, Local, No Upload

The short answer: APIs and JavaScript tooling consume JSON, and a CSV export is often where the data already lives. Converting CSV to JSON turns the first row into object keys and every following row into one record, producing a plain array you can paste into code, pipe into jq, or feed to an importer. Choose the delimiter and whether column names are trimmed. Press Convert, then use Download in the result panel to save the array.

How to convert CSV to JSON

Convert CSV to JSON now

The button opens the Excel Converter with CSV → JSON preselected — it runs entirely in your browser and nothing is uploaded.

Open Excel Converter

Local in your browser — nothing is uploaded

  1. Open the converter

    The button above opens the Excel Converter with the JSON output already selected.

  2. Drop your CSV file

    Add the file (up to 50.0 MiB); .xlsx workbooks are read sheet by sheet and CSV files are parsed with explicit quoting rules.

  3. Convert and download

    Press Convert to process the workbook in a dedicated worker. When the result appears, press Download to save it. Cancel stops an in-progress run.

Conversion facts

Input format
CSV
Output format
JSON
Max file size
50.0 MiB
Max dimensions
Worksheet XML ≤ 200.0 MiB · Output ≤ 32.0 MiB · ≤ 256 columns
Quality
Value-level — formulas use cached values, styles dropped
Processing
Local in your browser — nothing is uploaded

CSV

CSV → JSON

What to watch

Values only, exactly as text: no types are guessed, so leading zeros, long numbers and formula-like strings survive intact. Blank or duplicate header names are rejected instead of silently overwriting each other. Input files are capped at 50 MiB and the JSON output at 32 MiB; for pasted text rather than whole files, the structured-data converter handles text-level CSV to JSON.

Keep converting

Related conversions

Continue with Toolars

  • The tool behind this page

    Excel Converter

    Convert .xlsx workbooks to CSV or JSON, or CSV back to .xlsx, entirely in the browser — values only, with an optional UTF-8 BOM marker (EF BB BF) for CSV. Check decoding in your target app. Inputs up to 50 MiB, outputs up to 32 MiB.

  • Not sure which tool fits the job?

    Structured Data Converter

    It also handles CSV ⇄ JSON from pasted text up to 256 KiB — this matrix covers whole files up to 50 MiB instead.

Frequently asked questions

What exactly survives the conversion?
Only cell values. Formulas contribute the value cached by the app that saved the file — they are never recalculated — and styles, merged cells, and column widths are dropped. Date cells become ISO strings like 2026-09-20.
What are the file limits?
Inputs up to 50.0 MiB are converted locally in your browser (a .xlsx ZIP may expand to 200 MiB of worksheet XML), and outputs are capped at 32 MiB with at most 256 columns. Anything past a limit is refused with a clear message instead of being silently truncated.