Convert CSV to JSON, Excel and more

To convert a CSV file, drop it on the converter above and check the table. Pick an output such as JSON or Excel, and press Download. The converter works out the delimiter and the text encoding for you. It runs entirely in your browser, so the file is never uploaded.

How do I convert a CSV file?

1. Drop a file on the converter, choose Open a file, or paste text. Copying cells from Excel or Google Sheets and pasting them works too.
2. Look at the Table tab. Each column shows the kind of values it holds, such as whole numbers, dates or text. If the columns look wrong, change Delimiter or Encoding in the toolbar.
3. Tidy up if you need to. Click a column name to rename, move, trim or remove it, or use Columns to edit them all at once. Remove duplicates drops repeated rows.
4. Pick the output format on the right. The preview updates as you change options.
5. Press Copy or Download. Both include every row, even when the preview shows only the first 500.

Which formats can it read and write?

Format	Read	Write	Good to know
CSV and TSV	Yes	Yes	Any delimiter in; comma, semicolon, tab or pipe out, with an optional UTF-8 mark for Excel.
Excel (.xlsx)	Yes	Yes	Pick the sheet to read. Written workbooks get a bold, frozen, filtered header row.
JSON and JSON Lines	Yes	Yes	A list of objects, a list of lists, or an object keyed by a column. Nested objects become columns like address.city.
SQL	INSERT statements	CREATE TABLE and INSERT	PostgreSQL, MySQL, SQLite and SQL Server, each with its own quoting.
Markdown	Tables	Tables	Pipes inside cells are escaped; number columns can be right-aligned.
HTML	Tables	Tables	Reads the largest table on a page you paste.
YAML	Lists	Lists	Strings that YAML could misread, like no or 1.0, are quoted.

Why do accents or emoji look wrong in my CSV?

A CSV file does not say which text encoding it uses. Most modern files are UTF-8. Older Windows exports often use Windows-1252, and some systems write UTF-16. The converter checks for a byte-order mark, then tries UTF-8. It falls back to Windows-1252 if the bytes are not valid UTF-8, and the status line says so. If names still look like René, pick another encoding from the toolbar and the table reloads at once.

Going the other way, Excel often misreads UTF-8 CSV files that have no byte-order mark. Tick UTF-8 mark for Excel before you download, or download an Excel workbook instead.

How are numbers, dates and blanks handled?

The tool reads every value as text, then checks each column as a whole. A column counts as numbers only if every value in it is a number. So one stray “n/a” keeps the column as text instead of half-converting it. Values with a leading zero stay text. With Numbers as numbers on, JSON, YAML, SQL and Excel get real numbers and true/false values. Turn on Blanks as null to write empty cells as null (or NULL in SQL) instead of empty strings.

How big a file can it handle?

The work runs in a background thread, so the page stays responsive while a file loads, and you can cancel at any time. The table preview draws only the rows on screen, so scrolling a million rows feels like scrolling a hundred. In our test on a recent MacBook in Chromium, a 100,000-row, 8.5 MB CSV opened in about a tenth of a second, became JSON in under a fifth of a second, and became a 5 MB Excel workbook in about two seconds.

Related tools

Checking JSON before you convert it? The JSON Formatter shows exactly where it breaks. Comparing two exports? The Diff Checker shows every change side by side.