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Data Type Detection

Infer the real type of each column and flag bad values.

About Data Type Detection

Scan a dataset and infer whether each column is an integer, decimal, date, boolean, email, URL or free text — then list the rows that do not match, so you can find the three malformed dates hiding in fifty thousand records.

A column is either numeric or it is not, and one stray cell breaks the distinction. The consequences are quiet: sums skip text cells, sorting puts 100 before 20, charts drop what they cannot read.

Scan the sheet and see what each column actually contains.

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How Data Type Detection works in your browser

Every value in a column is tested against a series of patterns — integer, decimal, date, boolean, email, URL, plain text — and the column is reported as the type that fits all of its values, along with the count of any that do not.

The exceptions are the point. A column reported as 998 integers and 2 text values is telling you exactly where to look, and finding those two cells by scrolling is what the tool saves you.

Dates deserve particular attention, because a date column is the one most likely to be silently wrong. A spreadsheet stores a date as a number wearing a display format, and ambiguous values like 03/04/2026 read two ways — a misreading that is invisible for any day above the twelfth and wrong for the rest.

When to use it

  • Finding the one text cell that is stopping a column from summing.
  • Validating a dataset before importing it into a system with typed columns.
  • Checking whether a date column was parsed the way you assumed.
  • Identifying which columns hold email addresses or URLs before processing them.

Read more about this

Why your Excel dates break when you export to CSVDates turn into numbers, days and months swap places, and leading zeros vanish. Here is what a spreadsheet actually stores in a date cell, and how to export so the other side reads it correctly.How to clean up a messy spreadsheetThe order to do it in, why trailing spaces defeat duplicate detection, how a single text cell poisons a numeric column, and how to clean a spreadsheet without uploading the data in it.

Frequently asked questions

Which types can it recognise?

Integers, decimals, dates, booleans, emails, URLs and free text, inferred from the values actually present rather than from the header.

How does it help me find bad data?

It lists the rows that do not match the inferred type — the three malformed dates in ten thousand rows, or the email column with two entries missing an @.

What if a column is genuinely mixed?

It is reported as text with the exceptions listed, so you can decide whether the mixture is intentional or a data quality problem.

Related tools

Excel to JSON Convert sheets into arrays of objects. Spreadsheet Cleaner Trim, normalise and tidy messy data in one pass. Remove Duplicate Rows Deduplicate on all columns or a chosen key. Remove Blank Rows & Columns Delete empty rows, columns and trailing whitespace. Column Statistics Profile every column: count, mean, median, min, max, unique. Excel to Word Turn spreadsheet sheets into formatted Word tables.