Java tutorial
//package com.java2s; public class Main { public static String GetFileSizeStr(long size) { if (size > 1000 * 1000 * 1000) { return String.format("%.2f GB", size / (double) (1000 * 1000 * 1000)); } else if (size > 1000 * 1000) { return String.format("%.2f MB", size / (double) (1000 * 1000)); } else if (size > 1000) { return String.format("%.2f KB", size / (double) (1000)); } else { return String.format("%d B", size); } } }