Convert Excel to CSV
A CSV is rows of text separated by commas and nothing else. An XLSX is a workbook: many sheets, formulas, number formats, merged cells, charts. Converting means keeping the first of those and discarding the rest, and the three things people are surprised by are that formulas arrive as values, that only one sheet comes out, and that a number formatted as currency arrives as a bare number.
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What it does
- Formulas are exported as their computed values
- Only the first sheet of the workbook is written
- Number and date formatting is dropped; the underlying value remains
How to use Excel to CSV
- 1
Upload the workbook
An .xlsx from Excel, LibreOffice, Google Sheets or anything that writes the format.
- 2
The first sheet becomes the file
CSV has no concept of multiple sheets, so the first one is exported. Move the sheet you want to the front before uploading if it is not already there.
- 3
Check the numbers, not the formatting
A cell showing 1,234.50 with a currency symbol arrives as 1234.5. The value is intact; the presentation was never in the cell.
How it works
The workbook is opened, the first sheet is selected, and each row is written as a line of comma-separated values. Cells containing formulas contribute their cached computed value, because that is what a data file can hold.
Fields containing a comma, a quotation mark or a line break are quoted so the file parses correctly. This is the part of CSV that most hand-rolled exports get wrong, and it is why a converter is worth using over a copy and paste.
The three things that surprise people
Formulas become values. The CSV is a snapshot, not a live calculation.
Only one sheet comes out. CSV has no notion of a workbook. If the file you needed was on the third tab, it is not in the output.
Formatting is not data. A number displayed as a date, a percentage or a currency is stored as a plain number with a display rule attached. The rule does not travel, so 0.15 shown as 15% arrives as 0.15.
When CSV is the right target
Anything that is going to be read by a program. Databases, statistical tools, data pipelines and import forms all prefer CSV precisely because it has no features: there is nothing to interpret beyond rows, fields and quoting.
When it is not
Anything a person will open and work in. Sending a colleague a CSV of a report strips the formatting, the sheets and the formulas that made it readable. Send the XLSX, or a PDF if it must not be edited.
What you are deliberately throwing away
Everything except the values in one sheet. Formulas become the numbers they last produced, so nothing recalculates afterwards. Formatting, colors, column widths, conditional rules, charts and comments are all gone. Additional sheets are not exported.
That is not a failure of the conversion; it is what CSV is. The format holds rows of values and has no concept of anything else.
It is worth being deliberate about because the loss is silent. A CSV opens without complaint and looks complete, and there is nothing in it to indicate that the workbook it came from had four other sheets and a set of formulas driving the column you are now reading as fixed numbers. Keep the XLSX.
Examples
An export for a data pipeline
The pipeline gets numbers it can parse rather than formulas it would have to evaluate. Two sheets did not come across, which is the thing to check before assuming the export is complete.
A price list with formatted currency
The trailing zero on 4.50 is gone because it was a display rule, not part of the number. Anything downstream that needs two decimals must apply that itself.
Frequently asked questions
Why did my formulas disappear?
They did not disappear; they were resolved. A CSV has no way to store a formula, so each cell is written as the value the formula produced at the time of conversion. This is almost always what is wanted, because the destination is usually a script or a database that needs data rather than a calculation. What it does mean is that the CSV is a snapshot and will not update when the source workbook changes.
What happened to my other sheets?
A CSV file holds exactly one table, so only the first sheet of the workbook is exported. There is no standard way to put several sheets in one CSV, and inventing one would produce a file nothing else could read. If you need every sheet, export them one at a time by moving each to the front, or convert to ODS or XLSX where multiple sheets are native.
Will leading zeros in reference numbers survive?
In the CSV, yes: it is a text file and whatever the cell contained is written out. The risk comes later. Opening that CSV in a spreadsheet application often re-guesses types and can strip a leading zero from something like 00123, turning a reference into a number. If those identifiers matter, import the CSV rather than double-clicking it, and set the column to text.
Further reading
- XLSX Cost 14% More Than the CSV and the Old XLS Cost Nearly Four TimesThe modern spreadsheet formats have a reputation for bloat that they no longer deserve, and the old one has a reputation for compactness it never had. A plain table in four formats puts numbers on both, and the ranking is not the one most people would guess.
- We Sent a CSV Through a Spreadsheet and Watched What DiedOpen a CSV in a spreadsheet, change nothing, save it again, and the file that comes out is not the file that went in. This is well known for postcodes and product codes with leading zeros. We ran a deliberately awkward CSV through the round trip to find out exactly which fields survive and which do not.
- The Three Invisible Bytes at the Start of Your CSVYour CSV has a column called `id`. Your code looks for a column called `id`. It is not there. Print the header and it says `id`. The problem is three bytes at the very start of the file that no editor displays, that Excel on Windows once needed, and that half the software in the world now has to work around.