PHPExcel Accounting Formats
$objPHPExcel->getActiveSheet()->getStyle('C1')->getNumberFormat()->setFormatCode("#,##0.00");
or use
$objPHPExcel->getActiveSheet()->getStyle('C1')->getNumberFormat()->setFormatCode("#.##0,00");
Set in getStyle
CELL.
I reverse engineered the format code from an existing spreadsheet using PHPExcel and got this:
_("$"* #,##0.00_);_("$"* \(#,##0.00\);_("$"* "-"??_);_(@_)
This is the code Excel places on the cell when you select the "Accounting" format... or click that "$" toolbar button in Excel 2007.
If you didn't need currency symbol :
->setFormatCode("_(* #,##0.00_);_(* \(#,##0.00\);_(* \"-\"??_);_(@_)");