Open an Excel or CSV file, switch on the clean-up steps you need and see exactly which cells and rows change before you download the result — all on your device.
Excel Data Cleaner
Open an Excel or CSV file, switch on the clean-up steps you need and see exactly which cells and rows change before you download the result — all on your device.
The Excel Data Cleaner reads and cleans your spreadsheet in your browser. The file, its contents and the cleaned result stay on your device and are never uploaded.
Messy spreadsheets break lookups, pivot tables and imports for the same few reasons: stray spaces, hidden characters, blank rows, duplicate records, dates in five formats and numbers stored as text. The Excel Data Cleaner opens a workbook or CSV and lets you stack the fixes as ordered steps — trim, strip hidden characters, drop blank rows and columns, de-duplicate on chosen key columns, change case, standardise dates (including Excel serial numbers), convert text to numbers, find and replace, fill blanks, split and merge columns, and tidy headers. Each step shows how many cells or rows it changed, with a before-and-after sample, and changed cells are highlighted in a live preview. Your original file is never touched, and nothing is uploaded.
Features
Sixteen reorderable cleaning steps you can switch on and off, with live counts for each one
Before and after examples for the first changes of every step, and highlighted cells in the preview
Duplicate removal on the whole row or on chosen key columns, keeping the first or last match
Date standardising that reads mixed formats and Excel serial numbers, with a day-first or month-first setting
Text-to-number conversion for currency symbols, thousands separators, parentheses negatives and 1.234,56 style values
Leading zeros and long ID numbers stay as text so zip codes and account numbers survive
Find and replace with optional regular expressions, fill-down, split, merge and header tidying
Download the cleaned sheet as .xlsx or CSV, plus a copyable report of what changed
How to use the Excel Data Cleaner
Drop in an .xlsx, .xls, .csv or .tsv file, or try the sample sheet, and choose the sheet and header row
Switch on the steps you need, point each one at the right columns and move them into a sensible order
Check the counts, the before and after examples and the highlighted preview
Download the cleaned .xlsx or CSV and copy the change report if you need a record
Example
Input
Name: ' alice JOHNSON ' Email: 'ALICE@Example.com '
Date: '03/04/2025' Amount: '$1,200.00'
(the same row appears twice)
Output
Name: 'Alice Johnson' Email: 'alice@example.com'
Date: '2025-04-03' Amount: 1200 (a real number)
Duplicate row removed: 1 of 6 data rows
Steps ran in order: trim, remove duplicates, title case, email, date (day first) and text to number.
Common errors & troubleshooting
A duplicate row was not removed. — Rows only match when every compared cell is identical after trimming. Put the trim step before the duplicate step, turn on Ignore upper/lower case, or choose just the key columns such as the email address.
Dates came out with the day and month swapped. — A value like 03/04/2025 can be read two ways. Change the ambiguity setting on the date step between Day first and Month first; values such as 13/04/2025 are always read correctly.
Some numbers were left as text. — IDs with leading zeros and strings longer than 15 digits are kept as text on purpose. Turn off Keep IDs like 00123 as text if you really want them converted, and check the note under the step for skipped values.
The hidden-character step did not make a blank row disappear. — Order matters. Move Remove hidden characters above Remove blank rows so cells holding only invisible characters are empty by the time blank rows are checked.
Frequently asked questions
How does the Excel Data Cleaner decide a row is a duplicate?
It builds a key from the columns you pick, or from every column when none are picked, after trimming spaces. Rows with the same key are duplicates; you choose whether the first or the last one is kept and whether case matters.
Can the Excel Data Cleaner standardise dates that arrive in different formats?
Yes. The date step reads ISO dates, day-month-year and month-day-year numbers, month names like 5 Jan 2025, compact 20250105 values and Excel serial numbers such as 45000, then writes one format you choose, as text or as real date cells.
Will the Excel Data Cleaner change my original workbook?
No. The file you open is only read. Cleaning happens on a copy in memory and you download a new .xlsx or CSV, so the original stays exactly as it was.
What happens to formulas and formatting when I clean an Excel file?
Formulas are read as their last calculated values and written back as plain values, and cell styling, merged cells and charts are not carried over. The download is a clean data sheet rather than a copy of the original layout.
Why do some steps in the Excel Data Cleaner need a column chosen?
Steps such as case, dates, numbers and split need to know where to act, so you pick the columns with chips. Leaving the selection on All columns applies a step everywhere, while split and merge ask for specific columns.
Can I clean a large spreadsheet in the Excel Data Cleaner?
Yes, within what your browser can hold in memory. Tens of thousands of rows are handled comfortably, though the preview shows only the first 50 rows to keep the page responsive.
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