Open huge CSV, Excel, JSON and XML files in a grid

A 345 MB Excel workbook with 1,048,575 rows and 14 columns — the largest a .xlsx can hold. Opened in 9.9 s, using 119 MB of memory. The workbook was produced by converting a JSON file with DataFileConverter and then opened here; the numbers are the program's own status bar.

What it opens

• Delimited text: CSV, TSV, TXT (delimiter and header row detected, both can be changed)
• Excel .xlsx / .xlsm — choose the worksheet; numbers and dates are shown the way Excel formats them
• JSON / JSON Lines — a JSON viewer for files of any size: pick the record array from a structure tree, then read it as a grid; optionally expand nested objects into columns
• XML — an XML viewer that handles 700 MB documents: pick the record node the same way; attributes and child elements become columns

What you can do with a 12-million-row file

• Scroll, or type a row number in Go to row, or press Ctrl+Home / Ctrl+End
• Find a value in the whole file, browse the hits and jump to one
• Copy a selection, a whole column, a whole row or the whole page as TSV
• Export the current view as CSV or TSV
• Auto-fit the columns, hover a clipped cell to read it in full
• Open several files in tabs and reload them from the recent-files list

What it does not do

• It is a viewer: no editing, no sorting, no filters
• Formulas are not calculated — the cached value stored by Excel is shown
• Legacy .xls / .xlsb and password-protected workbooks are not supported (it says so, and suggests saving as .xlsx)

Try it, then buy it

Version 1.0. Free for 30 days with no limits; after the trial the free version keeps opening files up to 100 MB and 1,000,000 rows.

Download the free trial   Buy a license — 45.00