OpenSheet

OpenSheet is a fast, lightweight spreadsheet editor that works the same on the web, desktop, and mobile. Open Excel (.xlsx) and CSV files, edit them with formatting preserved, and save them back.

FEATURES • Excel compatible — open/save .xlsx and .csv with fonts, colors, borders, number formats, and merged cells preserved • 400+ functions — SUM, AVERAGE, IF, VLOOKUP and more, powered by a real formula engine • Charts — turn any selection into a bar, line, or pie chart, insert it onto the sheet, and it's embedded in the saved file • Conditional formatting — highlight cells automatically by their value • Data tools — sort, AutoFilter, find & replace, and data validation (dropdown lists) • Editing essentials — undo/redo, copy/cut/paste, auto-fill, freeze panes, and cell notes • Multiple sheets with cross-sheet references • Dark mode and English/Korean UI • Works offline, with autosave and recovery

PRIVACY Your files are opened and processed entirely on your device — nothing is uploaded to a server.

OpenSheet is also available as a free web app and as desktop apps for macOS, Windows, and Linux.