Practical guides on cleaning messy spreadsheets, fixing broken CSV and Excel exports, and preparing data for analysis — written from real, hands-on experience building a spreadsheet cleaning tool.
Blank cells aren't all the same kind of missing. A practical, non-academic guide to figuring out why data is missing and choosing the right fix — deletion, imputation, or leaving it alone — for real small business spreadsheets.
Customer info in one file, order history in another, and you need them combined. Here's how to merge two CSV files on a shared key using VLOOKUP, Power Query, or a no-code merge tool — and how to avoid the mistakes that quietly drop or duplicate rows.
One-hot encoding turns a categorical column like Region or Plan Type into binary indicator columns a model or pivot table can actually use. Here's how to do it by hand, and when to reach for a tool instead.
When a spreadsheet is edited by people in different countries and on different devices, its date column quietly turns into four or five formats at once. Here's how to standardize it safely.
That mysterious number like 44927 in your date column is an Excel serial date. Here's exactly what it means, why it happens, and how to convert it back to a real calendar date reliably.
Your VLOOKUP returns #N/A even though the values look identical on screen. Here's what's actually happening — invisible characters, non-breaking spaces, and how to find and strip them.
A practical, no-code walkthrough of finding and removing duplicate rows in a CSV file — including the sneaky near-duplicates that exact-match tools miss entirely.
Broken date formats and duplicate rows silently destroy analytical accuracy. Here is the definitive, technical guide to cleaning messy spreadsheets fast — entirely inside your browser, with zero data ever transmitted to a server.