log('Returns the interest rate for a fully invested security.'); // Create new PhpSpreadsheet object $spreadsheet = new Spreadsheet(); $worksheet = $spreadsheet->getActiveSheet(); // Add some data $arguments = [ ['Settlement Date', DateHelper::getDateValue('01-Apr-2005')], ['Maturity Date', DateHelper::getDateValue('31-Mar-2010')], ['Investment', 1000.00], ['Investment', 2125.00], ]; // Some basic formatting for the data $worksheet->fromArray($arguments, null, 'A1'); $worksheet->getStyle('B1:B2')->getNumberFormat()->setFormatCode('dd-mmm-yyyy'); $worksheet->getStyle('B3:B4')->getNumberFormat()->setFormatCode('$#,##0.00'); // Now the formula $worksheet->setCellValue('B7', '=INTRATE(B1, B2, B3, B4)'); $worksheet->getStyle('B7')->getNumberFormat()->setFormatCode('0.00%'); $helper->log($worksheet->getCell('B7')->getValue()); $helper->log('INTRATE() Result is ' . $worksheet->getCell('B7')->getFormattedValue());