How to Clean Spreadsheet Data Before Importing It

Check whitespace, duplicates, dates, and identifiers before an import.

A spreadsheet can look tidy while still containing problems that break an import. Cleaning the data first is easier than repairing a report after incorrect values have spread to other systems.

Protect identifiers

Make a working copy and identify columns that contain codes, dates, amounts, or free text. A code such as 00127 may need its leading zeros; treating it as a number changes the value.

Normalize with care

Trim accidental spaces, but do not automatically change capitalization in names, product codes, or case-sensitive fields. Decide what blank cells mean before replacing them with a standard value.

Test representative rows

Import a few rows containing commas, blank values, non-English characters, and leading zeros. Confirm that each field lands in the correct column before processing the full file.

Before relying on the result, test a small example, keep an original copy when a file or value is transformed, and check the output in the application where you plan to use it. Browse the tools directory for a utility that matches your task, and use the other practical guides for related checks.

Editorial note: This guide provides general educational information. Follow the requirements of the software, service, or organization involved when a task has specific rules.