Third-party implementations of Office Open XML exist on the Windows platform (LibreOffice, all platforms), OS X platform (iWork '08, LibreOffice) and Linux (LibreOffice and OpenOffice.org 3.0).
Доступен под Windows и Apple Mac OS X. Программы-эквиваленты: OpenOffice.org Calc, LibreOffice Calc, KSpread, StarOffice, Gnumeric, Corel Quattro Pro и Apple Numbers (только на платформе Mac OS).