JSON to CSV

How do I convert JSON to CSV for Excel?

1. Paste your JSON into the Input box. It should be an array of objects, or an object that contains one such as an API response.
2. Choose the Delimiter: Comma for UK Excel and Google Sheets, Semicolon (Excel in Europe) for continental locales, or Tab.
3. Leave Flatten nested objects (a.b.c) ticked so nested data becomes separate columns.
4. Click Convert to CSV and check the preview in the output panel.
5. Click Download to save a .csv file, or Copy output to paste it elsewhere.

The converter reads every object in the array, collects the full set of keys across all of them, and uses that as the header row, so objects that are missing a key simply get an empty cell rather than shifting the columns. If you paste an object rather than an array, the tool looks for the array of objects inside it, which handles the common API shape of { "data": [ ... ] } without editing.

Flatten nested objects (a.b.c) is what makes real-world JSON usable in a spreadsheet. An address block such as { "address": { "city": "Leeds", "postcode": "LS1" } } becomes two columns headed address.city and address.postcode. Arrays inside objects are written as their JSON text in a single cell, because there is no sensible way to spread a variable-length list across fixed columns. With flattening off, any nested object is written as JSON text instead.

Quoting follows the CSV rules Excel expects: any value containing the delimiter, a double quote or a line break is wrapped in double quotes, and quotes inside it are doubled. That means addresses with commas, product descriptions with line breaks and text containing inch marks all survive the round trip. Numbers and booleans are written plainly, null and missing values as empty cells.

Choose the delimiter to match where the file is going. UK, US and Irish Excel installs, and Google Sheets everywhere, expect commas. Excel in Germany, France, the Netherlands and most of the rest of Europe uses the comma as a decimal separator and so expects semicolons; open a comma file there and everything lands in column A. Tab is the safest choice for pasting into an existing sheet. The conversion runs in your browser tab; nothing is transmitted or stored, and exports of a few hundred thousand rows finish in a couple of seconds.

How it works: this tool uses plain JavaScript running in your browser tab. No server is involved, so Kilnfile never sees your file. Last reviewed 20 September 2026.

Frequently asked questions