Guides
Guides
Longer walkthroughs for the problems that bring people here: the file that will not open, the CSV that came out as one column, the dedupe nobody can audit.
- 4 min read
How to Anonymize a Data File Before You Share It
Find the personal data in a file and mask, hash, tokenize or generalize it — on your own machine, with every finding shown for you to confirm before anything is rewritten.
Read more - 5 min read
How to Clean a Data File Without Writing a Script
Fix the twenty things wrong with every export — whitespace, mixed date formats, numbers stored as text, lost leading zeros, bad encoding — in one previewable pass on your own PC.
Read more - 4 min read
How to Compare Two Excel Files and See Exactly What Changed
Compare two Excel, CSV or Parquet files on your own PC: schema drift, added and removed rows, and cell-level differences — with tolerances so float noise is not reported as a change.
Read more - 4 min read
How to Open a CSV File That Excel Will Not Open
Open and read CSV files of any size on Windows. Filter and sort against the file itself rather than a loaded copy, see the detected delimiter and encoding, and never upload anything.
Read more - 4 min read
How to Generate a Data Dictionary From a File You Already Have
Produce a data dictionary from a CSV, Excel or Parquet file: every column with its type, semantic role, null rate, range and sample values. Exports to .xlsx and Table Schema JSON.
Read more - 4 min read
How to Profile a Data File Before You Build Anything On It
Profile every column in a CSV, Excel or Parquet file: inferred type, semantic role, nulls, distinct counts, ranges, outliers and candidate keys — on your own machine, at any file size.
Read more - 4 min read
How to Score the Quality of a Data File — and Show Your Working
Measure a file's data quality across completeness, validity, uniqueness, consistency and structure — with the weights shown, so the score is auditable rather than a black box.
Read more - 3 min read
How to Merge Many CSV Files Into One
Combine a folder of CSV, Excel or Parquet files into a single table on your own PC — even when the columns do not match — with a source-file column so you can tell where each row came from.
Read more - 3 min read
How to Remove Duplicates and Prove What You Removed
Find and remove duplicate rows in Excel, CSV and Parquet files using exact, normalized or fuzzy matching — and get a report naming every row that went and what it matched.
Read more - 3 min read
How to Run SQL Against a CSV File Without a Database
Query CSV, Parquet, Excel and JSON files directly with SQL — join across formats, no import step, no server to set up, and nothing uploaded. Free for Windows.
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Looking for a one-off conversion instead? The free converters cover the common pairs.