How to use the Data Cleaning Tool
- 1. Load your CSVChoose a file or paste text; a column profile shows types, blanks and distinct values.
- 2. Tick the fixesChoose steps and the columns each one applies to.
- 3. CleanDownload the clean CSV and read exactly what changed.
What it fixes
- Spaces: trims, collapses double spaces and replaces non-breaking spaces.
- Empty rows and columns: removes them.
- Case: Title, UPPER or lower for the columns you pick.
- Numbers: "₹25,000", "1,20,000.50", "(1,500)" and "20000 Rs" become plain numbers. Lakh and crore words are left alone, so 5 lakh never becomes 5.
- Dates: 03/04/2026, 15-Apr-2026, 7.5.26 and Apr 15, 2026 become YYYY-MM-DD, day-first by default.
- Missing values: fills blanks with a value, the mean, the median or the most common value.
- Find and replace: plain text or a regular expression.
- Duplicates: removes repeated rows.
Files are read by your browser and never uploaded.
Worked example
The messy sample has 7 rows. Clean it with the default steps (title case on Name and City, numbers in Fee, dates in Joined) and you get 5 clean rows. One empty row and one duplicate are removed, 5 fees are cleaned ("(1,500)" becomes −1500) and 4 dates become YYYY-MM-DD ("7.5.26" becomes 2026-05-07). One impossible date, 31/13/2026, is left as it was and counted, so you can fix it by hand. Phone numbers keep their leading zeros because Phone wasn't ticked as a number column.
Trust, but check
- Nothing is silently lost: values the tool can't understand are left unchanged and counted in the log.
- The date rules were checked against Python's datetime on 400 random dates, including invalid ones like 31 February.
- "45%" becomes 0.45, as Excel stores percentages.
Frequently asked questions
Day first or month first?
Indian files are usually day first (03/04/2026 = 3 April). Choose month first for US-style exports.
Can I undo a step?
Your original file isn't changed. Untick the step and clean again.
Is the data cleaning tool free?
Yes. You can open the data cleaning tool, load files and set every option without signing up. When you clean a file for the first time, we ask once for your name and WhatsApp number; after that it, and every other Uncodemy tool, opens straight away.