Convert CSV to XLS
Free, fast CSV → XLS. No watermarks, no sign-up.
How to convert CSV to XLS
1. Upload CSV
Drop your CSV file into the converter above.
2. Confirm XLS
Output is already set to XLS. Adjust only if you need to.
3. Download
Convert and download your XLS file instantly.
Format Details
CSV
CSV (Comma-Separated Values) is a plain-text tabular data format that uses commas to delimit column values and line breaks to separate rows. It is one of the most universally supported data interchange formats, readable by any spreadsheet application, database, or programming language. CSV is ideal for exporting and importing data between different systems due to its simplicity, human readability, and near-universal compatibility.
dataXLS
XLS is the legacy binary spreadsheet format used by Microsoft Excel from 1987 through the Office 2003 era, based on Microsoft's proprietary Binary Interchange File Format (BIFF). It stores worksheets, formulas, charts, and macros in a binary structure that requires Microsoft's format specification to parse correctly. XLS remains common in older enterprise systems and when compatibility with legacy versions of Excel is required.
dataConverting CSV to XLS: what actually changes
CSV to XLS is one of the conversions this site performs, but the two formats are not interchangeable containers. Here is what the file keeps, what it loses, and how to get a result you can use.
What .CSV and .XLS each hold
.CSV is a data format built for analysing, importing or exchanging records, storing rows, columns and value types. .XLS is a data format built for analysing, importing or exchanging records, storing rows, columns and value types. Converting between them is a decision about which of those two jobs the result needs to do.
What changes in the conversion
Both files belong to the data category, so this is a like-for-like repackage: the same kind of content, stored in a different container. What changes is how .XLS encodes rows, columns and value types — not what the file is about.
When this conversion is the right one
Reach for .XLS when the software, device or platform you are sending to expects it — the content is the same data, only the packaging differs. The reverse direction works the same way, so you can always convert back from .XLS to .CSV using the same tool.
Tips for a clean CSV to XLS conversion
Start from the original file
Convert the .CSV you started with, not an earlier .XLS output. Every extra round trip costs quality and can accumulate formatting drift.
Check the real type, not the extension
Text/csv becomes application/vnd.ms-excel. If a file was renamed rather than converted, it will fail to open — rename it back to its true extension before uploading and the conversion will recognise it.
Confirm the structure first
Open the .CSV briefly and check delimiters, headers and encoding. A misplaced separator or a stray quote is the usual reason the output looks wrong even though the conversion succeeded.
Limits worth knowing
Uploads are capped per file (30 MB, or 100 MB for video) and processed temporarily — nothing is kept as a permanent copy. For huge data files, split or compress the source first.
Frequently Asked Questions
How do I convert CSV to XLS?
Upload your CSV file on Convertek, select XLS as the output format, then click Convert. Your XLS file will be ready to download instantly.
Is the CSV to XLS converter free?
Yes. Converting CSV to XLS on Convertek is completely free with no watermarks. Fair upload limits apply (typically 30 MB per file).
Is my file kept after conversion?
No. Files are processed temporarily and not stored permanently. Converted downloads are available only in your browser session.
What is the difference between CSV and XLS?
CSV and XLS are different file formats with distinct use cases. Converting between them lets you use your file in software or workflows that require the XLS format.