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IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Network0.0.0.0/2
Usable hosts1,073,741,822
Subnet mask192.0.0.0
Addresses1,073,741,824
Network address
0.0.0.0
Broadcast address
63.255.255.255
First usable
0.0.0.1
Last usable
63.255.255.254
Usable hosts
1,073,741,822 (1,073,741,824 less the network and broadcast addresses)
Subnet mask
192.0.0.0
Wildcard mask
63.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/2
Type
Public public
Old class
A (default /8)
As numbers
Hex 00000000 · Integer 0 to 1073741823
Reverse DNS zones
0.in-addr.arpa
1.in-addr.arpa
2.in-addr.arpa
3.in-addr.arpa
4.in-addr.arpa
5.in-addr.arpa
6.in-addr.arpa
7.in-addr.arpa
8.in-addr.arpa
9.in-addr.arpa
10.in-addr.arpa
11.in-addr.arpa
12.in-addr.arpa
13.in-addr.arpa
14.in-addr.arpa
15.in-addr.arpa
and 48 more
/2 is not on a 8-bit boundary, so it takes 64 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000000.00000000.00000000.000000000.0.0.0
Subnet mask11000000.00000000.00000000.00000000192.0.0.0
Network00000000.00000000.00000000.000000000.0.0.0
Broadcast00111111.11111111.11111111.1111111163.255.255.255
Split into smaller subnets/12
/3 (2)/4 (4)/5 (8)/6 (16)/7 (32)/8 (64)/9 (128)/10 (256)/11 (512)/12 (1,024)/13 (2,048)/14 (4,096)

0.0.0.0/2 makes 1,024 subnets of /12; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
10.0.0.0/120.0.0.1 to 0.15.255.2540.15.255.2551,048,574
20.16.0.0/120.16.0.1 to 0.31.255.2540.31.255.2551,048,574
30.32.0.0/120.32.0.1 to 0.47.255.2540.47.255.2551,048,574
40.48.0.0/120.48.0.1 to 0.63.255.2540.63.255.2551,048,574
50.64.0.0/120.64.0.1 to 0.79.255.2540.79.255.2551,048,574
60.80.0.0/120.80.0.1 to 0.95.255.2540.95.255.2551,048,574
70.96.0.0/120.96.0.1 to 0.111.255.2540.111.255.2551,048,574
80.112.0.0/120.112.0.1 to 0.127.255.2540.127.255.2551,048,574
90.128.0.0/120.128.0.1 to 0.143.255.2540.143.255.2551,048,574
100.144.0.0/120.144.0.1 to 0.159.255.2540.159.255.2551,048,574
110.160.0.0/120.160.0.1 to 0.175.255.2540.175.255.2551,048,574
120.176.0.0/120.176.0.1 to 0.191.255.2540.191.255.2551,048,574
130.192.0.0/120.192.0.1 to 0.207.255.2540.207.255.2551,048,574
140.208.0.0/120.208.0.1 to 0.223.255.2540.223.255.2551,048,574
150.224.0.0/120.224.0.1 to 0.239.255.2540.239.255.2551,048,574
160.240.0.0/120.240.0.1 to 0.255.255.2540.255.255.2551,048,574
171.0.0.0/121.0.0.1 to 1.15.255.2541.15.255.2551,048,574
181.16.0.0/121.16.0.1 to 1.31.255.2541.31.255.2551,048,574
191.32.0.0/121.32.0.1 to 1.47.255.2541.47.255.2551,048,574
201.48.0.0/121.48.0.1 to 1.63.255.2541.63.255.2551,048,574
211.64.0.0/121.64.0.1 to 1.79.255.2541.79.255.2551,048,574
221.80.0.0/121.80.0.1 to 1.95.255.2541.95.255.2551,048,574
231.96.0.0/121.96.0.1 to 1.111.255.2541.111.255.2551,048,574
241.112.0.0/121.112.0.1 to 1.127.255.2541.127.255.2551,048,574
251.128.0.0/121.128.0.1 to 1.143.255.2541.143.255.2551,048,574
261.144.0.0/121.144.0.1 to 1.159.255.2541.159.255.2551,048,574
271.160.0.0/121.160.0.1 to 1.175.255.2541.175.255.2551,048,574
281.176.0.0/121.176.0.1 to 1.191.255.2541.191.255.2551,048,574
291.192.0.0/121.192.0.1 to 1.207.255.2541.207.255.2551,048,574
301.208.0.0/121.208.0.1 to 1.223.255.2541.223.255.2551,048,574
311.224.0.0/121.224.0.1 to 1.239.255.2541.239.255.2551,048,574
321.240.0.0/121.240.0.1 to 1.255.255.2541.255.255.2551,048,574
332.0.0.0/122.0.0.1 to 2.15.255.2542.15.255.2551,048,574
342.16.0.0/122.16.0.1 to 2.31.255.2542.31.255.2551,048,574
352.32.0.0/122.32.0.1 to 2.47.255.2542.47.255.2551,048,574
362.48.0.0/122.48.0.1 to 2.63.255.2542.63.255.2551,048,574
372.64.0.0/122.64.0.1 to 2.79.255.2542.79.255.2551,048,574
382.80.0.0/122.80.0.1 to 2.95.255.2542.95.255.2551,048,574
392.96.0.0/122.96.0.1 to 2.111.255.2542.111.255.2551,048,574
402.112.0.0/122.112.0.1 to 2.127.255.2542.127.255.2551,048,574
412.128.0.0/122.128.0.1 to 2.143.255.2542.143.255.2551,048,574
422.144.0.0/122.144.0.1 to 2.159.255.2542.159.255.2551,048,574
432.160.0.0/122.160.0.1 to 2.175.255.2542.175.255.2551,048,574
442.176.0.0/122.176.0.1 to 2.191.255.2542.191.255.2551,048,574
452.192.0.0/122.192.0.1 to 2.207.255.2542.207.255.2551,048,574
462.208.0.0/122.208.0.1 to 2.223.255.2542.223.255.2551,048,574
472.224.0.0/122.224.0.1 to 2.239.255.2542.239.255.2551,048,574
482.240.0.0/122.240.0.1 to 2.255.255.2542.255.255.2551,048,574
493.0.0.0/123.0.0.1 to 3.15.255.2543.15.255.2551,048,574
503.16.0.0/123.16.0.1 to 3.31.255.2543.31.255.2551,048,574
513.32.0.0/123.32.0.1 to 3.47.255.2543.47.255.2551,048,574
523.48.0.0/123.48.0.1 to 3.63.255.2543.63.255.2551,048,574
533.64.0.0/123.64.0.1 to 3.79.255.2543.79.255.2551,048,574
543.80.0.0/123.80.0.1 to 3.95.255.2543.95.255.2551,048,574
553.96.0.0/123.96.0.1 to 3.111.255.2543.111.255.2551,048,574
563.112.0.0/123.112.0.1 to 3.127.255.2543.127.255.2551,048,574
573.128.0.0/123.128.0.1 to 3.143.255.2543.143.255.2551,048,574
583.144.0.0/123.144.0.1 to 3.159.255.2543.159.255.2551,048,574
593.160.0.0/123.160.0.1 to 3.175.255.2543.175.255.2551,048,574
603.176.0.0/123.176.0.1 to 3.191.255.2543.191.255.2551,048,574
613.192.0.0/123.192.0.1 to 3.207.255.2543.207.255.2551,048,574
623.208.0.0/123.208.0.1 to 3.223.255.2543.223.255.2551,048,574
633.224.0.0/123.224.0.1 to 3.239.255.2543.239.255.2551,048,574
643.240.0.0/123.240.0.1 to 3.255.255.2543.255.255.2551,048,574
654.0.0.0/124.0.0.1 to 4.15.255.2544.15.255.2551,048,574
664.16.0.0/124.16.0.1 to 4.31.255.2544.31.255.2551,048,574
674.32.0.0/124.32.0.1 to 4.47.255.2544.47.255.2551,048,574
684.48.0.0/124.48.0.1 to 4.63.255.2544.63.255.2551,048,574
694.64.0.0/124.64.0.1 to 4.79.255.2544.79.255.2551,048,574
704.80.0.0/124.80.0.1 to 4.95.255.2544.95.255.2551,048,574
714.96.0.0/124.96.0.1 to 4.111.255.2544.111.255.2551,048,574
724.112.0.0/124.112.0.1 to 4.127.255.2544.127.255.2551,048,574
734.128.0.0/124.128.0.1 to 4.143.255.2544.143.255.2551,048,574
744.144.0.0/124.144.0.1 to 4.159.255.2544.159.255.2551,048,574
754.160.0.0/124.160.0.1 to 4.175.255.2544.175.255.2551,048,574
764.176.0.0/124.176.0.1 to 4.191.255.2544.191.255.2551,048,574
774.192.0.0/124.192.0.1 to 4.207.255.2544.207.255.2551,048,574
784.208.0.0/124.208.0.1 to 4.223.255.2544.223.255.2551,048,574
794.224.0.0/124.224.0.1 to 4.239.255.2544.239.255.2551,048,574
804.240.0.0/124.240.0.1 to 4.255.255.2544.255.255.2551,048,574
815.0.0.0/125.0.0.1 to 5.15.255.2545.15.255.2551,048,574
825.16.0.0/125.16.0.1 to 5.31.255.2545.31.255.2551,048,574
835.32.0.0/125.32.0.1 to 5.47.255.2545.47.255.2551,048,574
845.48.0.0/125.48.0.1 to 5.63.255.2545.63.255.2551,048,574
855.64.0.0/125.64.0.1 to 5.79.255.2545.79.255.2551,048,574
865.80.0.0/125.80.0.1 to 5.95.255.2545.95.255.2551,048,574
875.96.0.0/125.96.0.1 to 5.111.255.2545.111.255.2551,048,574
885.112.0.0/125.112.0.1 to 5.127.255.2545.127.255.2551,048,574
895.128.0.0/125.128.0.1 to 5.143.255.2545.143.255.2551,048,574
905.144.0.0/125.144.0.1 to 5.159.255.2545.159.255.2551,048,574
915.160.0.0/125.160.0.1 to 5.175.255.2545.175.255.2551,048,574
925.176.0.0/125.176.0.1 to 5.191.255.2545.191.255.2551,048,574
935.192.0.0/125.192.0.1 to 5.207.255.2545.207.255.2551,048,574
945.208.0.0/125.208.0.1 to 5.223.255.2545.223.255.2551,048,574
955.224.0.0/125.224.0.1 to 5.239.255.2545.239.255.2551,048,574
965.240.0.0/125.240.0.1 to 5.255.255.2545.255.255.2551,048,574
976.0.0.0/126.0.0.1 to 6.15.255.2546.15.255.2551,048,574
986.16.0.0/126.16.0.1 to 6.31.255.2546.31.255.2551,048,574
996.32.0.0/126.32.0.1 to 6.47.255.2546.47.255.2551,048,574
1006.48.0.0/126.48.0.1 to 6.63.255.2546.63.255.2551,048,574
1016.64.0.0/126.64.0.1 to 6.79.255.2546.79.255.2551,048,574
1026.80.0.0/126.80.0.1 to 6.95.255.2546.95.255.2551,048,574
1036.96.0.0/126.96.0.1 to 6.111.255.2546.111.255.2551,048,574
1046.112.0.0/126.112.0.1 to 6.127.255.2546.127.255.2551,048,574
1056.128.0.0/126.128.0.1 to 6.143.255.2546.143.255.2551,048,574
1066.144.0.0/126.144.0.1 to 6.159.255.2546.159.255.2551,048,574
1076.160.0.0/126.160.0.1 to 6.175.255.2546.175.255.2551,048,574
1086.176.0.0/126.176.0.1 to 6.191.255.2546.191.255.2551,048,574
1096.192.0.0/126.192.0.1 to 6.207.255.2546.207.255.2551,048,574
1106.208.0.0/126.208.0.1 to 6.223.255.2546.223.255.2551,048,574
1116.224.0.0/126.224.0.1 to 6.239.255.2546.239.255.2551,048,574
1126.240.0.0/126.240.0.1 to 6.255.255.2546.255.255.2551,048,574
1137.0.0.0/127.0.0.1 to 7.15.255.2547.15.255.2551,048,574
1147.16.0.0/127.16.0.1 to 7.31.255.2547.31.255.2551,048,574
1157.32.0.0/127.32.0.1 to 7.47.255.2547.47.255.2551,048,574
1167.48.0.0/127.48.0.1 to 7.63.255.2547.63.255.2551,048,574
1177.64.0.0/127.64.0.1 to 7.79.255.2547.79.255.2551,048,574
1187.80.0.0/127.80.0.1 to 7.95.255.2547.95.255.2551,048,574
1197.96.0.0/127.96.0.1 to 7.111.255.2547.111.255.2551,048,574
1207.112.0.0/127.112.0.1 to 7.127.255.2547.127.255.2551,048,574
1217.128.0.0/127.128.0.1 to 7.143.255.2547.143.255.2551,048,574
1227.144.0.0/127.144.0.1 to 7.159.255.2547.159.255.2551,048,574
1237.160.0.0/127.160.0.1 to 7.175.255.2547.175.255.2551,048,574
1247.176.0.0/127.176.0.1 to 7.191.255.2547.191.255.2551,048,574
1257.192.0.0/127.192.0.1 to 7.207.255.2547.207.255.2551,048,574
1267.208.0.0/127.208.0.1 to 7.223.255.2547.223.255.2551,048,574
1277.224.0.0/127.224.0.1 to 7.239.255.2547.239.255.2551,048,574
1287.240.0.0/127.240.0.1 to 7.255.255.2547.255.255.2551,048,574
1298.0.0.0/128.0.0.1 to 8.15.255.2548.15.255.2551,048,574
1308.16.0.0/128.16.0.1 to 8.31.255.2548.31.255.2551,048,574
1318.32.0.0/128.32.0.1 to 8.47.255.2548.47.255.2551,048,574
1328.48.0.0/128.48.0.1 to 8.63.255.2548.63.255.2551,048,574
1338.64.0.0/128.64.0.1 to 8.79.255.2548.79.255.2551,048,574
1348.80.0.0/128.80.0.1 to 8.95.255.2548.95.255.2551,048,574
1358.96.0.0/128.96.0.1 to 8.111.255.2548.111.255.2551,048,574
1368.112.0.0/128.112.0.1 to 8.127.255.2548.127.255.2551,048,574
1378.128.0.0/128.128.0.1 to 8.143.255.2548.143.255.2551,048,574
1388.144.0.0/128.144.0.1 to 8.159.255.2548.159.255.2551,048,574
1398.160.0.0/128.160.0.1 to 8.175.255.2548.175.255.2551,048,574
1408.176.0.0/128.176.0.1 to 8.191.255.2548.191.255.2551,048,574
1418.192.0.0/128.192.0.1 to 8.207.255.2548.207.255.2551,048,574
1428.208.0.0/128.208.0.1 to 8.223.255.2548.223.255.2551,048,574
1438.224.0.0/128.224.0.1 to 8.239.255.2548.239.255.2551,048,574
1448.240.0.0/128.240.0.1 to 8.255.255.2548.255.255.2551,048,574
1459.0.0.0/129.0.0.1 to 9.15.255.2549.15.255.2551,048,574
1469.16.0.0/129.16.0.1 to 9.31.255.2549.31.255.2551,048,574
1479.32.0.0/129.32.0.1 to 9.47.255.2549.47.255.2551,048,574
1489.48.0.0/129.48.0.1 to 9.63.255.2549.63.255.2551,048,574
1499.64.0.0/129.64.0.1 to 9.79.255.2549.79.255.2551,048,574
1509.80.0.0/129.80.0.1 to 9.95.255.2549.95.255.2551,048,574
1519.96.0.0/129.96.0.1 to 9.111.255.2549.111.255.2551,048,574
1529.112.0.0/129.112.0.1 to 9.127.255.2549.127.255.2551,048,574
1539.128.0.0/129.128.0.1 to 9.143.255.2549.143.255.2551,048,574
1549.144.0.0/129.144.0.1 to 9.159.255.2549.159.255.2551,048,574
1559.160.0.0/129.160.0.1 to 9.175.255.2549.175.255.2551,048,574
1569.176.0.0/129.176.0.1 to 9.191.255.2549.191.255.2551,048,574
1579.192.0.0/129.192.0.1 to 9.207.255.2549.207.255.2551,048,574
1589.208.0.0/129.208.0.1 to 9.223.255.2549.223.255.2551,048,574
1599.224.0.0/129.224.0.1 to 9.239.255.2549.239.255.2551,048,574
1609.240.0.0/129.240.0.1 to 9.255.255.2549.255.255.2551,048,574
16110.0.0.0/1210.0.0.1 to 10.15.255.25410.15.255.2551,048,574
16210.16.0.0/1210.16.0.1 to 10.31.255.25410.31.255.2551,048,574
16310.32.0.0/1210.32.0.1 to 10.47.255.25410.47.255.2551,048,574
16410.48.0.0/1210.48.0.1 to 10.63.255.25410.63.255.2551,048,574
16510.64.0.0/1210.64.0.1 to 10.79.255.25410.79.255.2551,048,574
16610.80.0.0/1210.80.0.1 to 10.95.255.25410.95.255.2551,048,574
16710.96.0.0/1210.96.0.1 to 10.111.255.25410.111.255.2551,048,574
16810.112.0.0/1210.112.0.1 to 10.127.255.25410.127.255.2551,048,574
16910.128.0.0/1210.128.0.1 to 10.143.255.25410.143.255.2551,048,574
17010.144.0.0/1210.144.0.1 to 10.159.255.25410.159.255.2551,048,574
17110.160.0.0/1210.160.0.1 to 10.175.255.25410.175.255.2551,048,574
17210.176.0.0/1210.176.0.1 to 10.191.255.25410.191.255.2551,048,574
17310.192.0.0/1210.192.0.1 to 10.207.255.25410.207.255.2551,048,574
17410.208.0.0/1210.208.0.1 to 10.223.255.25410.223.255.2551,048,574
17510.224.0.0/1210.224.0.1 to 10.239.255.25410.239.255.2551,048,574
17610.240.0.0/1210.240.0.1 to 10.255.255.25410.255.255.2551,048,574
17711.0.0.0/1211.0.0.1 to 11.15.255.25411.15.255.2551,048,574
17811.16.0.0/1211.16.0.1 to 11.31.255.25411.31.255.2551,048,574
17911.32.0.0/1211.32.0.1 to 11.47.255.25411.47.255.2551,048,574
18011.48.0.0/1211.48.0.1 to 11.63.255.25411.63.255.2551,048,574
18111.64.0.0/1211.64.0.1 to 11.79.255.25411.79.255.2551,048,574
18211.80.0.0/1211.80.0.1 to 11.95.255.25411.95.255.2551,048,574
18311.96.0.0/1211.96.0.1 to 11.111.255.25411.111.255.2551,048,574
18411.112.0.0/1211.112.0.1 to 11.127.255.25411.127.255.2551,048,574
18511.128.0.0/1211.128.0.1 to 11.143.255.25411.143.255.2551,048,574
18611.144.0.0/1211.144.0.1 to 11.159.255.25411.159.255.2551,048,574
18711.160.0.0/1211.160.0.1 to 11.175.255.25411.175.255.2551,048,574
18811.176.0.0/1211.176.0.1 to 11.191.255.25411.191.255.2551,048,574
18911.192.0.0/1211.192.0.1 to 11.207.255.25411.207.255.2551,048,574
19011.208.0.0/1211.208.0.1 to 11.223.255.25411.223.255.2551,048,574
19111.224.0.0/1211.224.0.1 to 11.239.255.25411.239.255.2551,048,574
19211.240.0.0/1211.240.0.1 to 11.255.255.25411.255.255.2551,048,574
19312.0.0.0/1212.0.0.1 to 12.15.255.25412.15.255.2551,048,574
19412.16.0.0/1212.16.0.1 to 12.31.255.25412.31.255.2551,048,574
19512.32.0.0/1212.32.0.1 to 12.47.255.25412.47.255.2551,048,574
19612.48.0.0/1212.48.0.1 to 12.63.255.25412.63.255.2551,048,574
19712.64.0.0/1212.64.0.1 to 12.79.255.25412.79.255.2551,048,574
19812.80.0.0/1212.80.0.1 to 12.95.255.25412.95.255.2551,048,574
19912.96.0.0/1212.96.0.1 to 12.111.255.25412.111.255.2551,048,574
20012.112.0.0/1212.112.0.1 to 12.127.255.25412.127.255.2551,048,574
20112.128.0.0/1212.128.0.1 to 12.143.255.25412.143.255.2551,048,574
20212.144.0.0/1212.144.0.1 to 12.159.255.25412.159.255.2551,048,574
20312.160.0.0/1212.160.0.1 to 12.175.255.25412.175.255.2551,048,574
20412.176.0.0/1212.176.0.1 to 12.191.255.25412.191.255.2551,048,574
20512.192.0.0/1212.192.0.1 to 12.207.255.25412.207.255.2551,048,574
20612.208.0.0/1212.208.0.1 to 12.223.255.25412.223.255.2551,048,574
20712.224.0.0/1212.224.0.1 to 12.239.255.25412.239.255.2551,048,574
20812.240.0.0/1212.240.0.1 to 12.255.255.25412.255.255.2551,048,574
20913.0.0.0/1213.0.0.1 to 13.15.255.25413.15.255.2551,048,574
21013.16.0.0/1213.16.0.1 to 13.31.255.25413.31.255.2551,048,574
21113.32.0.0/1213.32.0.1 to 13.47.255.25413.47.255.2551,048,574
21213.48.0.0/1213.48.0.1 to 13.63.255.25413.63.255.2551,048,574
21313.64.0.0/1213.64.0.1 to 13.79.255.25413.79.255.2551,048,574
21413.80.0.0/1213.80.0.1 to 13.95.255.25413.95.255.2551,048,574
21513.96.0.0/1213.96.0.1 to 13.111.255.25413.111.255.2551,048,574
21613.112.0.0/1213.112.0.1 to 13.127.255.25413.127.255.2551,048,574
21713.128.0.0/1213.128.0.1 to 13.143.255.25413.143.255.2551,048,574
21813.144.0.0/1213.144.0.1 to 13.159.255.25413.159.255.2551,048,574
21913.160.0.0/1213.160.0.1 to 13.175.255.25413.175.255.2551,048,574
22013.176.0.0/1213.176.0.1 to 13.191.255.25413.191.255.2551,048,574
22113.192.0.0/1213.192.0.1 to 13.207.255.25413.207.255.2551,048,574
22213.208.0.0/1213.208.0.1 to 13.223.255.25413.223.255.2551,048,574
22313.224.0.0/1213.224.0.1 to 13.239.255.25413.239.255.2551,048,574
22413.240.0.0/1213.240.0.1 to 13.255.255.25413.255.255.2551,048,574
22514.0.0.0/1214.0.0.1 to 14.15.255.25414.15.255.2551,048,574
22614.16.0.0/1214.16.0.1 to 14.31.255.25414.31.255.2551,048,574
22714.32.0.0/1214.32.0.1 to 14.47.255.25414.47.255.2551,048,574
22814.48.0.0/1214.48.0.1 to 14.63.255.25414.63.255.2551,048,574
22914.64.0.0/1214.64.0.1 to 14.79.255.25414.79.255.2551,048,574
23014.80.0.0/1214.80.0.1 to 14.95.255.25414.95.255.2551,048,574
23114.96.0.0/1214.96.0.1 to 14.111.255.25414.111.255.2551,048,574
23214.112.0.0/1214.112.0.1 to 14.127.255.25414.127.255.2551,048,574
23314.128.0.0/1214.128.0.1 to 14.143.255.25414.143.255.2551,048,574
23414.144.0.0/1214.144.0.1 to 14.159.255.25414.159.255.2551,048,574
23514.160.0.0/1214.160.0.1 to 14.175.255.25414.175.255.2551,048,574
23614.176.0.0/1214.176.0.1 to 14.191.255.25414.191.255.2551,048,574
23714.192.0.0/1214.192.0.1 to 14.207.255.25414.207.255.2551,048,574
23814.208.0.0/1214.208.0.1 to 14.223.255.25414.223.255.2551,048,574
23914.224.0.0/1214.224.0.1 to 14.239.255.25414.239.255.2551,048,574
24014.240.0.0/1214.240.0.1 to 14.255.255.25414.255.255.2551,048,574
24115.0.0.0/1215.0.0.1 to 15.15.255.25415.15.255.2551,048,574
24215.16.0.0/1215.16.0.1 to 15.31.255.25415.31.255.2551,048,574
24315.32.0.0/1215.32.0.1 to 15.47.255.25415.47.255.2551,048,574
24415.48.0.0/1215.48.0.1 to 15.63.255.25415.63.255.2551,048,574
24515.64.0.0/1215.64.0.1 to 15.79.255.25415.79.255.2551,048,574
24615.80.0.0/1215.80.0.1 to 15.95.255.25415.95.255.2551,048,574
24715.96.0.0/1215.96.0.1 to 15.111.255.25415.111.255.2551,048,574
24815.112.0.0/1215.112.0.1 to 15.127.255.25415.127.255.2551,048,574
24915.128.0.0/1215.128.0.1 to 15.143.255.25415.143.255.2551,048,574
25015.144.0.0/1215.144.0.1 to 15.159.255.25415.159.255.2551,048,574
25115.160.0.0/1215.160.0.1 to 15.175.255.25415.175.255.2551,048,574
25215.176.0.0/1215.176.0.1 to 15.191.255.25415.191.255.2551,048,574
25315.192.0.0/1215.192.0.1 to 15.207.255.25415.207.255.2551,048,574
25415.208.0.0/1215.208.0.1 to 15.223.255.25415.223.255.2551,048,574
25515.224.0.0/1215.224.0.1 to 15.239.255.25415.239.255.2551,048,574
25615.240.0.0/1215.240.0.1 to 15.255.255.25415.255.255.2551,048,574

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.