CSV Import Doctor: Inspect Delimiters, Encoding and Spreadsheet Risks

A CSV file can look correct in a text editor but import into one column, split in unexpected places or silently change identifiers. CSV Import Doctor helps you inspect the underlying text before opening it in a spreadsheet program. It supports comma, semicolon, tab and pipe delimiters and common text encodings.

This is a diagnostic tool, not a CSV converter or formula executor. It does not rewrite or upload the file. If the application interprets cell contents in a special way, confirm the result in the application before saving. For sensitive files, remember that the website itself also includes ordinary third-party analytics/advertising scripts; the CSV inspector’s code does not transmit file contents to those services.

Why CSV imports go wrong

All your values appear in one column

A file may use semicolons or tabs, even if it has a .csv extension. Check the delimiter shown above and choose that character in your spreadsheet’s text-import dialog. A comma in a quoted field is not a separator. When a row contains "Toronto, Ontario", the quotation marks keep the location together as one field.

Identifiers lose their leading zeros

A value such as 00123 may be treated as a number and become 123. Postal codes, product IDs and account identifiers should generally be imported as text, not converted to numbers. Quotation marks around CSV fields do not always guarantee text treatment in the receiving application.

Dates change unexpectedly

A string such as 03/04/2026 is ambiguous across date conventions. A spreadsheet might interpret it as March 4 or April 3, or as plain text. Review the regional/date import settings and the expected format before importing.

Long identifiers are rounded or displayed in scientific notation

A 17-digit ID is not ordinary numeric data just because it contains digits. A spreadsheet may have numeric precision limits or choose scientific notation. Preserve these fields as text and compare them with the original CSV after import.

Formulas unexpectedly execute

Values beginning with characters such as =, +, - or @ can be interpreted as formulas by spreadsheet software in some contexts. This is especially important for CSV data obtained from other people. Inspect the source before opening it, treat suspect columns as text and avoid assuming that CSV quoting is a universal safety measure. The warning is not proof a cell is malicious.

Different rows have different numbers of columns

Some datasets legitimately have optional empty fields. Other times, a missing quotation mark, unintended delimiter, or partially exported record shifts the columns. The inspection shows the location of inconsistent records, but does not decide which business-data rows are valid.

Import safely in your spreadsheet program

The guidance selector above adapts to your inspection findings. Use the links below to check the official instructions for your installed release.

LibreOffice Calc

Open the CSV with File → Open, then review the Text Import dialog. Confirm the character set, language, separator and column types; set identifier columns to Text. The options for detecting special numbers and formatting quoted fields as text can affect date and identifier conversion. LibreOffice Text Import documentation · Opening CSV files

Apache OpenOffice Calc

Use File → Open and confirm the Text Import separator settings. Review the preview and set important identifier columns to text. The 4.1 Calc guide explains separator selection and special-number detection. Official OpenOffice CSV import guide

Gnumeric

Use File → Open and choose Text import (configurable), or use Data → Import Data → Import Text File where available. Gnumeric’s documented Text Import dialog lets you choose encoding, separators or fixed-width fields, text qualifiers, and column types across three steps. Exact controls may vary by installed version. Gnumeric Text Import manual

Calligra Sheets

Open the text/CSV file using the available import workflow, examine how columns are separated, and check identifiers and dates after import. A current step-by-step CSV dialog was not independently verified in Calligra, so use the help for your installed release rather than assuming Calc controls apply. Calligra project documentation

SoftMaker PlanMaker

Choose File → Open for CSV/text files and use the text import options for separators, text markers, character sets and column types. PlanMaker specifically documents setting a preview column to Text to preserve leading zeros. PlanMaker text format help

ONLYOFFICE Spreadsheet Editor

On the Data tab use Get data → From Local TXT/CSV when supported by your version. Review encoding, delimiter, text qualifier and numeric separators in its text import wizard. ONLYOFFICE CSV import guide

Apple Numbers

Open the delimited text file, then, before editing imported data, select the table and use Format → Table → Adjust Import Settings to review the delimiter, text qualifier and encoding. Apple’s guide notes that import settings can’t be adjusted after editing the imported table. Apple Numbers text import guide

Zoho Sheet

Choose File → Import and select the CSV. Check the import dialog’s delimiter, decimal and thousands separators, and decide whether to add a new sheet or replace existing data. Uploading into Zoho Sheet itself is a separate step from the browser-only inspection on this page. Zoho Sheet import instructions

How the inspector works and what it cannot guarantee

The tool scans text locally in your browser for common patterns. It handles double-quoted fields, escaped quotation marks and embedded line breaks, but is not a full conformance certificate. Detection is heuristic: some unusual or deliberately nonstandard CSV files may require manual separator selection. A warning for formula-like text, dates or identifiers is a possible import risk, not a claim that an application actually changed the value.

The JSON inspection report contains file metadata, issue categories and row/column positions, not the raw cell contents. It is not an automatically repaired file. Maximum file size: 5 MiB. The tool currently supports UTF-8, Windows-1252 and UTF-16LE encodings; encoding cannot always be detected reliably. CSV files are plain text and do not preserve spreadsheet formatting or formulas reliably across programs.

For format conventions, see RFC 4180 and OWASP’s CSV injection guidance. You can also follow the site’s guides organized by task, formula compatibility library or editorial standards.