Press F9 to recalculate formulas in all open workbooks.
Press Shift+F9 to recalculate formulas in the active worksheet.
Press Ctrl+Alt+F9 to recalculate all formulas in all open workbooks, regardless of whether formulas have changed.
Press Ctrl+Shift+Alt+F9 to recheck dependent formulas in all open workbooks, regardless of whether formulas have changed.