Can I change CSV separators without replacing punctuation inside cells?

Yes. The parser recognizes quoted fields, embedded quotes and line breaks. It changes field separators, rather than blindly replacing every comma or semicolon in your text.

Does the tool preserve leading zeros and long identifiers?

Columns stay as text by default. Leading-zero values are retained and flagged even in a selected numeric column. The tool does not use floating-point arithmetic for number normalization. When opening the result in Excel, import identifier columns as text to prevent Excel from changing them.

What happens to invalid dates or unclear numbers?

They remain unchanged and receive review notes. Select the source date order and number conventions explicitly, then review the before-and-after preview before downloading.

Are my files or CSV values stored in saved presets?

No. Presets store only conversion settings and column indexes in your browser. They do not contain filenames, column headings or cell values.

CSV Delimiter Converter & Format Fixer

Change a CSV separator and review number or date changes column by column before downloading the result.

Your file stays on your device. Up to 5 MB, 50,000 rows and 200 columns. File contents are never saved.

Choose file

CSV file or text

Input separatorOutput separator

First row contains headings

My presets

Only settings are saved in this browser, never files or their contents.

Output and limitations

Change separators without replacing text inside cells

Select the source and destination separators, then build the preview. The parser treats quoted values as fields, so punctuation inside a quoted address or note is not the same as the separator between columns.

Choose number and date columns explicitly

Leave identifiers and codes as text. Select only columns that should be normalized, specify the source decimal/thousands marks and date order, and inspect changed cells. Ambiguous or invalid values remain unchanged with a warning.

Open the result carefully in Excel

Download UTF-8 CSV with the delimiter your destination expects. The output is still CSV, not an Excel workbook. Excel may reinterpret identifiers when opening a file; use its text/CSV import and mark important code columns as text.

Privacy and processing

CSV processing runs in this tab. Presets store only settings and column indexes in this browser, never filenames, headings or cell contents. Optional analytics sends fixed action labels only.

How to use CSV Delimiter Converter & Format Fixer

1Choose a CSV, TSV or text file, paste data, or try the European sample. Files can be up to 5 MB.
2Select the input and output separator, then build a preview. Leave identifiers as text.
3Choose exactly which columns contain numbers or dates. Set the source decimal, thousands separator and date order; review highlighted changes and notes.
4Download the cleaned CSV. Save a named preset if you want to reuse these settings; file contents and headings are not stored.

What you can do

Proper CSV parsing
Preserve quoted delimiters, embedded quotes and multiline cells.
Selected columns
Normalize decimal or date columns without changing unrelated text.
Safe review
Preserve leading-zero identifiers and flag values that do not match the chosen format.
Repeat use
Save and delete up to ten local settings presets without uploading documents.

When this tool helps

European CSV exports

Switch separators and decimal conventions with a visible review.

Calendar or contact preparation

Clean a source table before using a specific import tool.

About CSV Delimiter Converter & Format Fixer

This CSV format fixer changes field separators without blindly replacing punctuation inside cells. It supports comma, semicolon, tab and pipe delimiters. Selected numeric columns can use a decimal comma or decimal point and validated thousands groups; arithmetic uses text normalization rather than floating-point rounding, so long reference values do not silently lose precision. Date conversion requires an explicit order and outputs ISO dates. Unrecognized numbers and invalid dates are left unchanged with review notes. Leading-zero values remain unchanged. UTF-8 BOM output helps Excel recognize accented text, but Excel can still infer its own types: import identifiers through Data → From Text/CSV as text. Formula protection prefixes potentially executable text with an apostrophe; review these intentional changes in the preview. The tool does not create XLSX files, repair arbitrary encodings or guarantee downstream software will preserve types. For calendar files, use the ICS and CSV converter; for contacts, use CSV to VCF. Follow the calendar CSV preparation and import steps for event columns, date order and time zones. For phone-number columns and contact mapping, read how to prepare and import an Excel contact list.

ToolsWebPro provides this tool free with no account required. Each tool explains its supported formats, processing limits and privacy behavior.

Frequently asked questions

Can I change CSV separators without replacing punctuation inside cells?: Yes. The parser recognizes quoted fields, embedded quotes and line breaks. It changes field separators, rather than blindly replacing every comma or semicolon in your text.
Does the tool preserve leading zeros and long identifiers?: Columns stay as text by default. Leading-zero values are retained and flagged even in a selected numeric column. The tool does not use floating-point arithmetic for number normalization. When opening the result in Excel, import identifier columns as text to prevent Excel from changing them.
What happens to invalid dates or unclear numbers?: They remain unchanged and receive review notes. Select the source date order and number conventions explicitly, then review the before-and-after preview before downloading.
Are my files or CSV values stored in saved presets?: No. Presets store only conversion settings and column indexes in your browser. They do not contain filenames, column headings or cell values.

Step-by-step tutorials and troubleshooting written for this tool.

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