CSV to Excel

When Excel opens a CSV directly, it guesses the type of every cell. 00142 becomes 142, a 16-digit order ID becomes 1.23457E+15 and loses its last digits, and values such as 3-4 or MARCH1 can turn into dates. Saving the file then writes those changes back. Our article on moving between Excel and CSV without data loss covers the common cases.

This converter avoids the guessing. It writes every value into the workbook as a text cell, exactly as it appears in the CSV, so the workbook opens with your data unchanged.

Because every cell is text, Excel marks numeric-looking cells with a small green triangle, and formulas such as SUM skip them. When you need to calculate on a column, select it and choose Convert to Number from the warning menu, or use Data > Text to Columns > Finish. Columns you leave alone keep their leading zeros.

The workbook has one sheet named Sheet1, with your header row in row 1. No formatting, column widths, or formulas are added.

A sheet is limited to 100,000 data rows and 500 columns. Larger inputs are rejected with a message rather than silently cut off. The workbook is built entirely in your browser, so very large files depend on your device's memory.

Comma- and tab-separated input are both accepted; tabs are detected from the header line. Quoted fields with commas or line breaks are parsed correctly, and a line break inside a cell becomes a line break inside the Excel cell.