note 97549 deleted from function.pow by hholzgra

Note Submitter: Anonymous ---- You can increase the 'precision' php.ini setting a little to work with larger float numbers here, but this comes at at cost of sacrificing decimal accuracy. The default 'precision' is 14. 5 is about the threshhold that php can handle for decimal accuracy before at least some number corruption starts showing or it cannot output the actual number, and 16 for large number accuracy, as demonstrated by throwing this into the table below: <?php echo "<td>".pow(10, $i) - 1)."</td>"; ?> See the table below for an example, and adjust your php.ini 'precision' setting according to what your OS and PHP version can handle and what number size you want to work with. Alternatively, you can use the bc math functions for more accuracy all around, and not have to rely on the 'precision' ini setting at all, but this moves out of the realm of strictly floats and into strings. Also, PHP just prefers to display the 'E' notation of float values where possible after about 5 decimal places rather than the actual decimal number (1.0E-5 vs 0.00005). <?php echo "<table>"; for($i = 0; $i < 50; $i++) { $precision = $i + 1; ini_set('precision', $precision); echo "<tr>"; echo "<td>".$precision."</td>"; echo "<td>".pow(10, $i)."</td>"; echo "<td>".pow(10, (-1 * $i))."</td>"; echo "<td>".bcpow('10', (string) $i, $precision)."</td>"; echo "<td>".bcpow('10', (string) (-1 * $i), $precision)."</td>"; echo "</tr>"; } echo "</table>"; ?> Bottom line though is, if you're working with larger numbers or require very fine decimal precision or prefer displaying the full decimal number, use the bc math functions instead. And, do check out PHP's considerations about the float type here: http://php.net/manual/en/language.types.float.php