Subnet Mask Information

The following figures may be useful in filling in a IPv4 Address Space Request Form

 addrs bits pref   mask             

     1   0  /32    255.255.255.255
     2   1  /31    255.255.255.254
     4   2  /30    255.255.255.252
     8   3  /29    255.255.255.248
    16   4  /28    255.255.255.240
    32   5  /27    255.255.255.224
    64   6  /26    255.255.255.192
   128   7  /25    255.255.255.128
   256   8  /24    255.255.255    
   512   9  /23    255.255.254    
   1 K  10  /22    255.255.252    
   2 K  11  /21    255.255.248    
   4 K  12  /20    255.255.240    
   8 K  13  /19    255.255.224    
  16 K  14  /18    255.255.192    
  32 K  15  /17    255.255.128    
  64 K  16  /16    255.255        
 128 K  17  /15    255.254        
 256 K  18  /14    255.252        
 512 K  19  /13    255.248        
   1 M  20  /12    255.240        
   2 M  21  /11    255.224        
   4 M  22  /10    255.192        
   8 M  23  /9     255.128        
  16 M  24  /8     255            
  32 M  25  /7     254            
  64 M  26  /6     252            
 128 M  27  /5     248            
 256 M  28  /4     240            
 512 M  29  /3     224            
1024 M  30  /2     192            

hosts   subn/c  subn/c  subn/b  subn/b  bits hex-mask dec-mask
                strict          strict

    2     64      62    16384   16382     2  fffffffc 255.255.255.252
    6     32      30     8192    8190     3  fffffff8 255.255.255.248
   14     16      14     4096    4094     4  fffffff0 255.255.255.240
   30      8       6     2048    2046     5  ffffffe0 255.255.255.224
   62      4       2     1024    1022     6  ffffffc0 255.255.255.192
  126      2       0      512     510     7  ffffff80 255.255.255.128
  254                     256     254     8  ffffff00 255.255.255.0
  510                     128     126     9  fffffe00 255.255.254.0
 1022                      64      62    10  fffffc00 255.255.252.0
 2046                      32      30    11  fffff800 255.255.248.0
 4094                      16      14    12  fffff000 255.255.240.0
 8190                       8       6    13  ffffe000 255.255.224.0
16382                       4       2    14  ffffc000 255.255.192.0
32766                       2       0    15  ffff8000 255.255.128.0