Get free space on internal memory

this post might fit well to your question.

also check this thread. there is so much info here on SO.

googled a bit and here is the solution (found at android git)

File path = Environment.getDataDirectory();StatFs stat = new StatFs(path.getPath());long blockSize = stat.getBlockSize();long availableBlocks = stat.getAvailableBlocks();return Formatter.formatFileSize(this, availableBlocks * blockSize);

/*************************************************************************************************Returns size in bytes.If you need calculate external memory, change this:     StatFs statFs = new StatFs(Environment.getRootDirectory().getAbsolutePath());to this:     StatFs statFs = new StatFs(Environment.getExternalStorageDirectory().getAbsolutePath());        **************************************************************************************************/    public long TotalMemory()    {        StatFs statFs = new StatFs(Environment.getRootDirectory().getAbsolutePath());           long   Total  = ( (long) statFs.getBlockCount() * (long) statFs.getBlockSize());        return Total;    }    public long FreeMemory()    {        StatFs statFs = new StatFs(Environment.getRootDirectory().getAbsolutePath());        long   Free   = (statFs.getAvailableBlocks() * (long) statFs.getBlockSize());        return Free;    }    public long BusyMemory()    {        StatFs statFs = new StatFs(Environment.getRootDirectory().getAbsolutePath());           long   Total  = ((long) statFs.getBlockCount() * (long) statFs.getBlockSize());        long   Free   = (statFs.getAvailableBlocks()   * (long) statFs.getBlockSize());        long   Busy   = Total - Free;        return Busy;    }

Converting bytes to human readable format (like 1 Mb, 1 Gb)

    public static String floatForm (double d)    {       return new DecimalFormat("#.##").format(d);    }    public static String bytesToHuman (long size)    {        long Kb = 1  * 1024;        long Mb = Kb * 1024;        long Gb = Mb * 1024;        long Tb = Gb * 1024;        long Pb = Tb * 1024;        long Eb = Pb * 1024;        if (size <  Kb)                 return floatForm(        size     ) + " byte";        if (size >= Kb && size < Mb)    return floatForm((double)size / Kb) + " Kb";        if (size >= Mb && size < Gb)    return floatForm((double)size / Mb) + " Mb";        if (size >= Gb && size < Tb)    return floatForm((double)size / Gb) + " Gb";        if (size >= Tb && size < Pb)    return floatForm((double)size / Tb) + " Tb";        if (size >= Pb && size < Eb)    return floatForm((double)size / Pb) + " Pb";        if (size >= Eb)                 return floatForm((double)size / Eb) + " Eb";        return "???";    }

It looks like the StatFs class might be what you need to use. I'm not sure what path would be considered the root of the device, but I believe the result would be the same regardless of directory, as long as it's part of the internal storage. Something like this may work:

StatFs stats = new StatFs("/data");int availableBlocks = stats.getAvailableBlocks();int blockSizeInBytes = stats.getBlockSize();int freeSpaceInBytes = availableBlocks * blockSizeInBytes;

If nothing else, the StatFs class should give you a good start on where to look.