What are some alternatives?
When comparing Keikai and Microsoft Office Excel, you can also consider the following products
EtherCalc - EtherCalc is a web spreadsheet.
LibreOffice - Calc - LibreOffice Calc is the spreadsheet program you've always needed. A fork of OpenOffice.
Google Sheets - Synchronizing, online-based word processor, part of Google Drive.
Magic Spreadsheet - Human workforce and AI plugged into your Google Spreadsheets
Apache OpenOffice Calc - Calc, part of the https://alternativeto.
Gnumeric - Gnumeric