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CSV to Excel converter

Upload or paste a CSV and download it as an .xlsx file. Leading zeros in phone numbers, account numbers and codes are kept as text, so Excel does not strip them.

On-device: your files never leave this device

Choose a CSV file

or drop it anywhere on this page. You can also paste CSV text below.

Or paste CSV text

How to convert CSV to Excel

  1. Upload a CSV file or paste the text into the box.
  2. Check the delimiter it has detected: comma, semicolon or tab.
  3. Look over the preview to make sure the columns line up.
  4. Download the .xlsx file and open it in Excel.

Why Excel strips leading zeros from CSV files

When you double-click a CSV, Excel guesses the type of every value. Anything that looks like a number is stored as a number, and numbers do not have leading zeros. So the phone number 07700 900123 becomes 7700900123, a customer ID of 00451 becomes 451, and the change is saved if you then save the file.

This converter treats values with leading zeros as text when it builds the .xlsx file, so they open in Excel exactly as they appear in the CSV. That matters for UK mobile and landline numbers, sort codes, product codes and IDs exported from other systems.

If you only have Excel, the manual workaround is Data, then From Text/CSV, and setting those columns to Text before loading. It works, but it has to be done every time.

Commas, semicolons and tabs

CSV stands for comma separated values, but not every CSV uses commas. Files exported in countries that use a comma as the decimal point often use semicolons instead, and some systems export tab separated files. A file opened with the wrong delimiter puts every row into a single column.

The converter detects the delimiter for you and shows a preview, so you can see the columns are split correctly before you download. Values wrapped in double quotes, such as an address containing commas, stay together in one cell.

Once the columns look right, download the .xlsx file. Opening that file is safe to repeat as often as you like, because Excel reads the stored cell types instead of guessing again each time.

Questions people ask

Is my CSV uploaded anywhere?

No. The file is read and converted in your browser, which matters for customer lists and bank exports.

Why does my CSV open in one column in Excel?

Excel expected a different delimiter from the one in the file, often commas vs semicolons. Converting to .xlsx here fixes the columns for good.

Will my phone numbers keep the 0 at the start?

Yes. Values with leading zeros are stored as text in the .xlsx file, so 07700 900123 stays as it is.

Can I edit the file in Google Sheets or Numbers?

Yes. Both open .xlsx files, as does LibreOffice.

Why convert to .xlsx at all?

A CSV is plain text, so Excel reinterprets it every time you open it. An .xlsx file stores each cell with its type, so what you see stays fixed, and you can add formatting, formulas and more sheets.