How it is calculated
Choose the original file and check its name and preview. Select the original encoding yourself if the automatic suggestion looks wrong. With a BOM, UTF-8 or UTF-16 is used; without one, UTF-8 is tested first. This English page suggests Windows-1252 for other byte sequences. Bytes alone cannot always establish the encoding.
For example, if UTF-8 Peña appears as Peña, choose UTF-8 as the original encoding. If the original was saved as Windows-1252, choose Windows-1252. Characters already saved as ? require a fresh original.
When the preview matches, save UTF-8 BOM CSV or XLSX. CSV writes the decoded text in UTF-8 with a BOM; XLSX stores cells as strings. Check the receiving system’s delimiter and encoding requirements separately.
Download an encoding practice CSV
This file contains no personal data. Choose Windows-1252 and check Peña, áéíóúñ and the leading zero.
Examples
| Situation | Detection | Download |
|---|---|---|
Shopify order export shows José in Excel | UTF-8 (no BOM) | CSV (UTF-8 BOM) → opens correctly |
| CSV saved from Excel breaks accents when uploaded to a web app | Windows-1252 | CSV (UTF-8 BOM) → works in both |
Order ID 202609060001234 displays as 2.02609E+14 | any | .xlsx (all cells stored as text) |
Common mistakes
- Re-saving in Excel undoes the fix if you choose "CSV (Comma delimited)". Pick "CSV UTF-8 (Comma delimited)" instead.
- This does not repair characters already lost. If a previous save replaced letters with
?, that information is gone — re-export the original file and convert that. - All data in one column is a delimiter/locale issue (semicolon vs comma), not encoding. The preview will show a single column in that case.
- Files containing customer data are processed locally, but where you store or send the converted file remains your responsibility under privacy law.
FAQ
Is my file uploaded anywhere?
No. The file is read and converted entirely in your browser tab. Open the Network tab in developer tools and you will see no upload request. Close the page and the data is gone.
Why does Excel show é or ’ instead of é or ’?
Depending on its version and import method, Excel may read a BOM-less UTF-8 file using the system code page, while most web exports are UTF-8 without BOM. Check the original encoding and preview before saving.
Should I download the CSV (UTF-8 BOM) or the .xlsx?
Choose CSV if you will import the file into another system (shipping carrier, accounting software). Choose .xlsx if a person will open it in Excel — it also stores every cell as text, so order numbers do not turn into 1.23E+11 and leading zeros in ZIP codes and phone numbers survive.
Can it convert UTF-8 back to a legacy code page?
Not yet. Save as .xlsx here, then in Excel use Save As → "CSV (Comma delimited)", which writes the legacy encoding your locale uses.
What is the size limit?
50 MB. Everything runs in browser memory, so split larger exports first. There is no row limit; the preview shows the first 20 rows.