PHPSpreadsheet and writing large numbers of decimal places

Question

I'm having difficulty with PHPSpreadsheet when creating an XLSX file and attempting to write large numbers of decimal places to numerical values.

PHPSpreadsheet is rounding my 14 decimal place numbers, but I need them stored exactly as presented.

I'm using setFormatCode('0.00000000000000') as described in the documentation, but it's not working as I would expect.

Here's my test code:

<?php

require __DIR__ . '/vendor/autoload.php'; // Installed via composer

$spreadsheet = new \PhpOffice\PhpSpreadsheet\Spreadsheet();

$array = [
         0.03790728347833,
      1345.28748532874927,
    121345.18248762894914, // all 14 DP
];

$format = '0.00000000000000'; // 14 DP

// write the data
$spreadsheet->getActiveSheet()
    ->fromArray($array, null, 'A1');

// Format the cells
$spreadsheet->getActiveSheet()->getStyle('A1:C1')->getNumberFormat()->setFormatCode($format);

// Column sizing
foreach(range('A','C') as $columnID)
{
    $spreadsheet->getActiveSheet()->getColumnDimension($columnID)->setAutoSize(true);
}

$writer = new \PhpOffice\PhpSpreadsheet\Writer\Xlsx($spreadsheet);
$writer->save("test.xlsx");

// A1 = 0.03790728347833 - same
// A2 = 1345.28748532870000 - rounded
// A3 = 121345.18248763000000 - rounded

Could anyone provide a way to store this many decimal places without rounding?

Answer 1

This appears to be a limitation of Excel rather than PHPSpreadsheet.

Excel is limited to 15 significant figures according to Wikipedia.