Excel Changes Codes into Dates: Preserve the Column as Text

Decide that these values are identifiers

The field's purpose determines its type. In this example, 3-4 names an item; it is not March 4, April 3, a subtraction, or a fraction. Quantity is numeric because it is counted. Keeping the two columns different avoids forcing the whole file into one interpretation.

Record the code's exact spelling in the source system. Punctuation, leading zeros, and letter case can matter to another application even when two entries look similar to a person. Do not add spaces or remove punctuation merely to prevent Excel's date detection: that creates a different identifier.

Prevent conversion during manual entry

Select the empty code cells before typing. In Excel desktop, open Format Cells with Ctrl+1, choose Text, and confirm. Then enter 3-4, 12/2, and A-17. Keep the quantity column General or Number. A formula such as =ISTEXT(A2) should return TRUE for the code.

For an isolated entry, typing an apostrophe before the code is another Excel entry method. Enter '3-4 in the cell; Excel displays 3-4. This is an instruction to Excel during cell entry, not a general CSV escaping convention. Do not add apostrophes to the raw CSV unless the receiving system explicitly requires them.

C2: =ISTEXT(A2)        Expected: TRUE
D2: =LEN(A2)           Expected: 3
E2: =EXACT(A2,"3-4")   Expected: TRUE

Import the CSV with an explicit code type

Use Data > Get Data > From File > From Text/CSV, then Transform Data. In the query editor, inspect the Applied Steps before loading. If a guessed type step already converted item_code, remove or edit that conversion and return to the original text values. Merely adding a Text step after the conversion preserves the converted date's text, not necessarily the original code.

Set item_code to Text and quantity to Whole Number, check the preview against the sample, and load the table. If you use the legacy Text Import Wizard instead, select the code column in its final data preview and choose Text. Menu availability differs by Excel version.

1. Start from a preserved copy of the CSV.
2. Inspect every code column, including columns that currently contain only digits.
3. Load the typed result and compare the first, last, and date-like codes with the source.
4. Save a workbook copy as XLSX if you need to retain workbook cell types.

Related help: Keep other identifier columns as text during import

Recover from the source, not the date display

Suppose a converted cell now displays a calendar date. Formatting it as Text may reveal a serial number or another representation of that date. Neither tells you whether the source was 3-4, 03-04, or another spelling that Excel accepted. A reconstruction formula would be guessing.

Return to the untouched export, source application, or a known-good version and repeat the import with Text selected. Keep the damaged workbook separately until record counts and identifiers agree. If no original remains, mark uncertain codes for review instead of presenting reconstructed values as verified.

Do not rely on a single global setting

Some current Excel versions expose Automatic Data Conversion options, including a control for continuous letter-and-number strings that resemble dates. That control does not justify assuming every slash or hyphen code is protected. An explicit Text import remains a clear rule for an identifier column across mixed data and different recipients.

Quoting 3-4 as a CSV field also does not declare a text data type: CSV quotes organize fields. After exporting, reopen a copy through the same controlled import route and compare exact values. The Column Harbor checker can flag selected risks in UTF-8 CSV; it cannot reverse Excel's earlier conversion or modify the workbook.