That is Scientific Notation.
AND you are getting 388 instead of 311 because you are dividing by 1000000 instead of 1048576 (1024 * 1024)
EDIT: 311 is not achieved even with 1048576, that way you get 370... so the error is probably in your calc ;)
As described here , you just have to convert your Scientific Notation to a Decimal Notation through a Formatter.
DecimalFormat df = new DecimalFormat("#.########");
return df.format(fileLengthMegabytes);
Running Example: http://ideone.com/2lkKv7
import java.util.*;
import java.lang.*;
import java.text.*;
class Main
{
public static void main (String[] args) throws java.lang.Exception
{
DecimalFormat df = new DecimalFormat("#.##########");
float fileLengthMegabytes1 = (float) 388 / 1000000;
float fileLengthMegabytes2 = (float) 388 / 1048576;
System.out.println("MB1 in Scientific Notation: " +
fileLengthMegabytes1);
System.out.println("MB1 in Decimal Notation: " +
df.format(fileLengthMegabytes1));
System.out.println("MB2 in Scientific Notation: " +
fileLengthMegabytes2);
System.out.println("MB2 in Decimal Notation: " +
df.format(fileLengthMegabytes2));
}
}
Output:
MB1 in Scientific Notation: 3.88E-4
MB1 in Decimal Notation: 0.000388
MB2 in Scientific Notation: 3.7002563E-4
MB2 in Decimal Notation: 0.0003700256
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