File tools

12 tools for the data files and archives that land on your desk: spreadsheets that will not import, CSVs that are too big, JSON that will not parse and files that are not what they say.

Data

Files

Which tool for which job

You want toUse
Get a CSV out of a workbook, including an old .xlsExcel to CSV
Open a CSV in Excel without losing leading zerosCSV to Excel
Import a CSV that is over a row or size limitSplit CSV
Combine monthly exports into one fileMerge CSV
Fix stray spaces, blank rows and duplicatesClean CSV
Turn a spreadsheet into JSON for code or backCSV to JSON, JSON to CSV
Find the error in JSON that’ll not parseJSON formatter
Find out what a file with the wrong name really isFile type checker
Check a download matches its published checksumFile hash
Open a zip without installing anything or make oneUnzip, Create zip

Data and files

The Data tools work on the contents of tabular and structured files. They parse properly rather than splitting on commas, so a quoted value containing a comma or a line break stays in its column and they read the semicolon and tab separated files that European Excel and many exports produce. The Files tools work on files as a whole: what they’re, whether they are intact and packing or unpacking them.

Why data files go wrong

Most problems come from a program guessing. Excel guesses that 00501 is a number and drops the zeros, that a 16-digit reference is a number and rounds it and that 3-4 is a date. A system exporting CSV guesses an encoding and an importer guesses a different one. JSON parsers guess that every number fits in a double. Each tool here is built around not guessing or telling you when it has to.

Privacy

The files these tools handle are some of the most sensitive anyone works with: customer lists, payroll, orders, logs, API responses with keys in them. None of it is uploaded. The work happens in this tab and closing it discards everything.

Guides

Common questions

Are my files uploaded?

No. CSV, Excel, JSON and zip files are read and rewritten in your browser and nothing you paste into a box is transmitted. That matters for the customer lists, payroll exports and API responses that make up most of what people clean and convert.

How large a file can these tools handle?

Hundreds of megabytes for CSV splitting and merging and whatever your browser’s memory allows for the rest. There is no upload, so there is no upload limit. The file type checker and hash tool read files of any size, since they only need part of the file or read it in pieces.

Will converting change my data?

Only where a format forces it and the tools say so. CSV to Excel keeps values like 00123 and long ID numbers exactly as written instead of letting Excel reinterpret them. Excel to CSV writes each cell’s value, since CSV can’t hold formulas or formatting.

Do I need Excel installed?

No. The spreadsheet tools read .xlsx, the older .xls, .ods and Numbers files themselves and write standard .xlsx that Excel, Google Sheets, Numbers and LibreOffice all open.

Can these tools open password-protected files?

No. A protected workbook or zip needs its password to be read at all and the tools say so rather than failing silently. Remove the password in the program that created the file, then try again.