Tool 03

📅 Fix Date and Number Formats in Excel

Turns dates stored as text into real Excel dates, shows long numbers in full, converts numbers stored as text and restores lost ZIP code zeros.

🔒 Works offline — your file never leaves your computer

What it does

Text dates like "3/4/2026", "2026-03-04" or "March 4, 2026" become real Excel dates that sort and calculate correctly
All dates get one display format of your choice (MM/DD/YYYY, M/D/YYYY, MMM D, YYYY or YYYY-MM-DD)
Long numbers that Excel shows as 1.23457E+11 are displayed with all their digits again
Numbers stored as text — "1,250", "$1,250.00", "(45.10)", "12.5%" — become real numbers
ZIP codes that lost their leading zero are repaired: 2110 → 02110

Example

Before	After
March 4, 2026 (text)	03/04/2026 (real date)
1.23457E+11	123456789012
$1,250.00 (text)	$1,250.00 (number)
2110	02110

Real output of the tool with the default settings.

⬇ Download Tool — Free

or use it right here in your browser →

Single HTML file · opens in Chrome, Edge, Firefox or Safari · no installation, no sign-up

How it works

Download the toolClick the red button and save the file to your computer.

Open it in your web browserDouble-click the downloaded file. It opens in your browser — not in Excel. No installation, no account.

Choose your Excel file and save the cleaned copyClick "Run", check the before/after examples on screen, then save. Your original file stays untouched.

Good to know

Always keep a copy of your original file as a backup and check the cleaned copy before you use it.
Dates like 03/04/2026 are read month-first (March 4) by default. For data from Europe, switch to day-first before running.
If a number arrives as text that already reads "1.23E+11", the missing digits were lost before — they cannot be restored and the tool tells you where.
Phone, ZIP and ID columns and values with leading zeros are never turned into numbers.
Reads .xlsx, .xls and .csv files and saves the result as a new .xlsx file.
Only the first worksheet is cleaned. Other worksheets and title rows above your table are kept unchanged.
Values, dates and number formats are kept. Cell colors and fonts are not carried over to the cleaned copy.
The tools are provided free of charge and "as is". We have built and tested them with great care, but we cannot guarantee that every entry is recognized or changed correctly. As far as permitted by law, we accept no liability for results or any damage arising from their use. See Legal Notice & Disclaimer.

More about this tool

Dates and numbers that come from exports, websites or other programs often end up as text in Excel. They look right, but they won't sort, filters don't work and formulas return errors. At the same time Excel likes to "help" by turning long account numbers into 1.23457E+11 and dropping the leading zero of ZIP codes like 02110.

This tool repairs these problems column by column. Text that is clearly a date becomes a real Excel date in the format you choose. Long numbers are shown in full again. Amounts stored as text become numbers you can add up, and ZIP codes get their zeros back.

The tool is careful: it only converts values it can read without guessing. Phone numbers, ZIP codes, IDs and anything with a leading zero stay text. Numbers whose digits were already cut off before the file reached you are listed on screen instead of being "fixed" with made-up zeros.

You open the tool in your browser, choose your file and save a cleaned copy. Nothing is uploaded and your original stays untouched.

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