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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.

Network0.0.0.0/3
Usable hosts536,870,910
Subnet mask224.0.0.0
Addresses536,870,912
Network address
0.0.0.0
Broadcast address
31.255.255.255
First usable
0.0.0.1
Last usable
31.255.255.254
Usable hosts
536,870,910 (536,870,912 less the network and broadcast addresses)
Subnet mask
224.0.0.0
Wildcard mask
31.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/3
Type
Public public
Old class
A (default /8)
As numbers
Hex 00000000 · Integer 0 to 536870911
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 16 more
/3 is not on a 8-bit boundary, so it takes 32 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00000000.00000000.00000000.000000000.0.0.0
Subnet mask11100000.00000000.00000000.00000000224.0.0.0
Network00000000.00000000.00000000.000000000.0.0.0
Broadcast00011111.11111111.11111111.1111111131.255.255.255
Split into smaller subnets/11
/4 (2)/5 (4)/6 (8)/7 (16)/8 (32)/9 (64)/10 (128)/11 (256)/12 (512)/13 (1,024)/14 (2,048)/15 (4,096)

0.0.0.0/3 makes 256 subnets of /11.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
10.0.0.0/110.0.0.1 to 0.31.255.2540.31.255.2552,097,150
20.32.0.0/110.32.0.1 to 0.63.255.2540.63.255.2552,097,150
30.64.0.0/110.64.0.1 to 0.95.255.2540.95.255.2552,097,150
40.96.0.0/110.96.0.1 to 0.127.255.2540.127.255.2552,097,150
50.128.0.0/110.128.0.1 to 0.159.255.2540.159.255.2552,097,150
60.160.0.0/110.160.0.1 to 0.191.255.2540.191.255.2552,097,150
70.192.0.0/110.192.0.1 to 0.223.255.2540.223.255.2552,097,150
80.224.0.0/110.224.0.1 to 0.255.255.2540.255.255.2552,097,150
91.0.0.0/111.0.0.1 to 1.31.255.2541.31.255.2552,097,150
101.32.0.0/111.32.0.1 to 1.63.255.2541.63.255.2552,097,150
111.64.0.0/111.64.0.1 to 1.95.255.2541.95.255.2552,097,150
121.96.0.0/111.96.0.1 to 1.127.255.2541.127.255.2552,097,150
131.128.0.0/111.128.0.1 to 1.159.255.2541.159.255.2552,097,150
141.160.0.0/111.160.0.1 to 1.191.255.2541.191.255.2552,097,150
151.192.0.0/111.192.0.1 to 1.223.255.2541.223.255.2552,097,150
161.224.0.0/111.224.0.1 to 1.255.255.2541.255.255.2552,097,150
172.0.0.0/112.0.0.1 to 2.31.255.2542.31.255.2552,097,150
182.32.0.0/112.32.0.1 to 2.63.255.2542.63.255.2552,097,150
192.64.0.0/112.64.0.1 to 2.95.255.2542.95.255.2552,097,150
202.96.0.0/112.96.0.1 to 2.127.255.2542.127.255.2552,097,150
212.128.0.0/112.128.0.1 to 2.159.255.2542.159.255.2552,097,150
222.160.0.0/112.160.0.1 to 2.191.255.2542.191.255.2552,097,150
232.192.0.0/112.192.0.1 to 2.223.255.2542.223.255.2552,097,150
242.224.0.0/112.224.0.1 to 2.255.255.2542.255.255.2552,097,150
253.0.0.0/113.0.0.1 to 3.31.255.2543.31.255.2552,097,150
263.32.0.0/113.32.0.1 to 3.63.255.2543.63.255.2552,097,150
273.64.0.0/113.64.0.1 to 3.95.255.2543.95.255.2552,097,150
283.96.0.0/113.96.0.1 to 3.127.255.2543.127.255.2552,097,150
293.128.0.0/113.128.0.1 to 3.159.255.2543.159.255.2552,097,150
303.160.0.0/113.160.0.1 to 3.191.255.2543.191.255.2552,097,150
313.192.0.0/113.192.0.1 to 3.223.255.2543.223.255.2552,097,150
323.224.0.0/113.224.0.1 to 3.255.255.2543.255.255.2552,097,150
334.0.0.0/114.0.0.1 to 4.31.255.2544.31.255.2552,097,150
344.32.0.0/114.32.0.1 to 4.63.255.2544.63.255.2552,097,150
354.64.0.0/114.64.0.1 to 4.95.255.2544.95.255.2552,097,150
364.96.0.0/114.96.0.1 to 4.127.255.2544.127.255.2552,097,150
374.128.0.0/114.128.0.1 to 4.159.255.2544.159.255.2552,097,150
384.160.0.0/114.160.0.1 to 4.191.255.2544.191.255.2552,097,150
394.192.0.0/114.192.0.1 to 4.223.255.2544.223.255.2552,097,150
404.224.0.0/114.224.0.1 to 4.255.255.2544.255.255.2552,097,150
415.0.0.0/115.0.0.1 to 5.31.255.2545.31.255.2552,097,150
425.32.0.0/115.32.0.1 to 5.63.255.2545.63.255.2552,097,150
435.64.0.0/115.64.0.1 to 5.95.255.2545.95.255.2552,097,150
445.96.0.0/115.96.0.1 to 5.127.255.2545.127.255.2552,097,150
455.128.0.0/115.128.0.1 to 5.159.255.2545.159.255.2552,097,150
465.160.0.0/115.160.0.1 to 5.191.255.2545.191.255.2552,097,150
475.192.0.0/115.192.0.1 to 5.223.255.2545.223.255.2552,097,150
485.224.0.0/115.224.0.1 to 5.255.255.2545.255.255.2552,097,150
496.0.0.0/116.0.0.1 to 6.31.255.2546.31.255.2552,097,150
506.32.0.0/116.32.0.1 to 6.63.255.2546.63.255.2552,097,150
516.64.0.0/116.64.0.1 to 6.95.255.2546.95.255.2552,097,150
526.96.0.0/116.96.0.1 to 6.127.255.2546.127.255.2552,097,150
536.128.0.0/116.128.0.1 to 6.159.255.2546.159.255.2552,097,150
546.160.0.0/116.160.0.1 to 6.191.255.2546.191.255.2552,097,150
556.192.0.0/116.192.0.1 to 6.223.255.2546.223.255.2552,097,150
566.224.0.0/116.224.0.1 to 6.255.255.2546.255.255.2552,097,150
577.0.0.0/117.0.0.1 to 7.31.255.2547.31.255.2552,097,150
587.32.0.0/117.32.0.1 to 7.63.255.2547.63.255.2552,097,150
597.64.0.0/117.64.0.1 to 7.95.255.2547.95.255.2552,097,150
607.96.0.0/117.96.0.1 to 7.127.255.2547.127.255.2552,097,150
617.128.0.0/117.128.0.1 to 7.159.255.2547.159.255.2552,097,150
627.160.0.0/117.160.0.1 to 7.191.255.2547.191.255.2552,097,150
637.192.0.0/117.192.0.1 to 7.223.255.2547.223.255.2552,097,150
647.224.0.0/117.224.0.1 to 7.255.255.2547.255.255.2552,097,150
658.0.0.0/118.0.0.1 to 8.31.255.2548.31.255.2552,097,150
668.32.0.0/118.32.0.1 to 8.63.255.2548.63.255.2552,097,150
678.64.0.0/118.64.0.1 to 8.95.255.2548.95.255.2552,097,150
688.96.0.0/118.96.0.1 to 8.127.255.2548.127.255.2552,097,150
698.128.0.0/118.128.0.1 to 8.159.255.2548.159.255.2552,097,150
708.160.0.0/118.160.0.1 to 8.191.255.2548.191.255.2552,097,150
718.192.0.0/118.192.0.1 to 8.223.255.2548.223.255.2552,097,150
728.224.0.0/118.224.0.1 to 8.255.255.2548.255.255.2552,097,150
739.0.0.0/119.0.0.1 to 9.31.255.2549.31.255.2552,097,150
749.32.0.0/119.32.0.1 to 9.63.255.2549.63.255.2552,097,150
759.64.0.0/119.64.0.1 to 9.95.255.2549.95.255.2552,097,150
769.96.0.0/119.96.0.1 to 9.127.255.2549.127.255.2552,097,150
779.128.0.0/119.128.0.1 to 9.159.255.2549.159.255.2552,097,150
789.160.0.0/119.160.0.1 to 9.191.255.2549.191.255.2552,097,150
799.192.0.0/119.192.0.1 to 9.223.255.2549.223.255.2552,097,150
809.224.0.0/119.224.0.1 to 9.255.255.2549.255.255.2552,097,150
8110.0.0.0/1110.0.0.1 to 10.31.255.25410.31.255.2552,097,150
8210.32.0.0/1110.32.0.1 to 10.63.255.25410.63.255.2552,097,150
8310.64.0.0/1110.64.0.1 to 10.95.255.25410.95.255.2552,097,150
8410.96.0.0/1110.96.0.1 to 10.127.255.25410.127.255.2552,097,150
8510.128.0.0/1110.128.0.1 to 10.159.255.25410.159.255.2552,097,150
8610.160.0.0/1110.160.0.1 to 10.191.255.25410.191.255.2552,097,150
8710.192.0.0/1110.192.0.1 to 10.223.255.25410.223.255.2552,097,150
8810.224.0.0/1110.224.0.1 to 10.255.255.25410.255.255.2552,097,150
8911.0.0.0/1111.0.0.1 to 11.31.255.25411.31.255.2552,097,150
9011.32.0.0/1111.32.0.1 to 11.63.255.25411.63.255.2552,097,150
9111.64.0.0/1111.64.0.1 to 11.95.255.25411.95.255.2552,097,150
9211.96.0.0/1111.96.0.1 to 11.127.255.25411.127.255.2552,097,150
9311.128.0.0/1111.128.0.1 to 11.159.255.25411.159.255.2552,097,150
9411.160.0.0/1111.160.0.1 to 11.191.255.25411.191.255.2552,097,150
9511.192.0.0/1111.192.0.1 to 11.223.255.25411.223.255.2552,097,150
9611.224.0.0/1111.224.0.1 to 11.255.255.25411.255.255.2552,097,150
9712.0.0.0/1112.0.0.1 to 12.31.255.25412.31.255.2552,097,150
9812.32.0.0/1112.32.0.1 to 12.63.255.25412.63.255.2552,097,150
9912.64.0.0/1112.64.0.1 to 12.95.255.25412.95.255.2552,097,150
10012.96.0.0/1112.96.0.1 to 12.127.255.25412.127.255.2552,097,150
10112.128.0.0/1112.128.0.1 to 12.159.255.25412.159.255.2552,097,150
10212.160.0.0/1112.160.0.1 to 12.191.255.25412.191.255.2552,097,150
10312.192.0.0/1112.192.0.1 to 12.223.255.25412.223.255.2552,097,150
10412.224.0.0/1112.224.0.1 to 12.255.255.25412.255.255.2552,097,150
10513.0.0.0/1113.0.0.1 to 13.31.255.25413.31.255.2552,097,150
10613.32.0.0/1113.32.0.1 to 13.63.255.25413.63.255.2552,097,150
10713.64.0.0/1113.64.0.1 to 13.95.255.25413.95.255.2552,097,150
10813.96.0.0/1113.96.0.1 to 13.127.255.25413.127.255.2552,097,150
10913.128.0.0/1113.128.0.1 to 13.159.255.25413.159.255.2552,097,150
11013.160.0.0/1113.160.0.1 to 13.191.255.25413.191.255.2552,097,150
11113.192.0.0/1113.192.0.1 to 13.223.255.25413.223.255.2552,097,150
11213.224.0.0/1113.224.0.1 to 13.255.255.25413.255.255.2552,097,150
11314.0.0.0/1114.0.0.1 to 14.31.255.25414.31.255.2552,097,150
11414.32.0.0/1114.32.0.1 to 14.63.255.25414.63.255.2552,097,150
11514.64.0.0/1114.64.0.1 to 14.95.255.25414.95.255.2552,097,150
11614.96.0.0/1114.96.0.1 to 14.127.255.25414.127.255.2552,097,150
11714.128.0.0/1114.128.0.1 to 14.159.255.25414.159.255.2552,097,150
11814.160.0.0/1114.160.0.1 to 14.191.255.25414.191.255.2552,097,150
11914.192.0.0/1114.192.0.1 to 14.223.255.25414.223.255.2552,097,150
12014.224.0.0/1114.224.0.1 to 14.255.255.25414.255.255.2552,097,150
12115.0.0.0/1115.0.0.1 to 15.31.255.25415.31.255.2552,097,150
12215.32.0.0/1115.32.0.1 to 15.63.255.25415.63.255.2552,097,150
12315.64.0.0/1115.64.0.1 to 15.95.255.25415.95.255.2552,097,150
12415.96.0.0/1115.96.0.1 to 15.127.255.25415.127.255.2552,097,150
12515.128.0.0/1115.128.0.1 to 15.159.255.25415.159.255.2552,097,150
12615.160.0.0/1115.160.0.1 to 15.191.255.25415.191.255.2552,097,150
12715.192.0.0/1115.192.0.1 to 15.223.255.25415.223.255.2552,097,150
12815.224.0.0/1115.224.0.1 to 15.255.255.25415.255.255.2552,097,150
12916.0.0.0/1116.0.0.1 to 16.31.255.25416.31.255.2552,097,150
13016.32.0.0/1116.32.0.1 to 16.63.255.25416.63.255.2552,097,150
13116.64.0.0/1116.64.0.1 to 16.95.255.25416.95.255.2552,097,150
13216.96.0.0/1116.96.0.1 to 16.127.255.25416.127.255.2552,097,150
13316.128.0.0/1116.128.0.1 to 16.159.255.25416.159.255.2552,097,150
13416.160.0.0/1116.160.0.1 to 16.191.255.25416.191.255.2552,097,150
13516.192.0.0/1116.192.0.1 to 16.223.255.25416.223.255.2552,097,150
13616.224.0.0/1116.224.0.1 to 16.255.255.25416.255.255.2552,097,150
13717.0.0.0/1117.0.0.1 to 17.31.255.25417.31.255.2552,097,150
13817.32.0.0/1117.32.0.1 to 17.63.255.25417.63.255.2552,097,150
13917.64.0.0/1117.64.0.1 to 17.95.255.25417.95.255.2552,097,150
14017.96.0.0/1117.96.0.1 to 17.127.255.25417.127.255.2552,097,150
14117.128.0.0/1117.128.0.1 to 17.159.255.25417.159.255.2552,097,150
14217.160.0.0/1117.160.0.1 to 17.191.255.25417.191.255.2552,097,150
14317.192.0.0/1117.192.0.1 to 17.223.255.25417.223.255.2552,097,150
14417.224.0.0/1117.224.0.1 to 17.255.255.25417.255.255.2552,097,150
14518.0.0.0/1118.0.0.1 to 18.31.255.25418.31.255.2552,097,150
14618.32.0.0/1118.32.0.1 to 18.63.255.25418.63.255.2552,097,150
14718.64.0.0/1118.64.0.1 to 18.95.255.25418.95.255.2552,097,150
14818.96.0.0/1118.96.0.1 to 18.127.255.25418.127.255.2552,097,150
14918.128.0.0/1118.128.0.1 to 18.159.255.25418.159.255.2552,097,150
15018.160.0.0/1118.160.0.1 to 18.191.255.25418.191.255.2552,097,150
15118.192.0.0/1118.192.0.1 to 18.223.255.25418.223.255.2552,097,150
15218.224.0.0/1118.224.0.1 to 18.255.255.25418.255.255.2552,097,150
15319.0.0.0/1119.0.0.1 to 19.31.255.25419.31.255.2552,097,150
15419.32.0.0/1119.32.0.1 to 19.63.255.25419.63.255.2552,097,150
15519.64.0.0/1119.64.0.1 to 19.95.255.25419.95.255.2552,097,150
15619.96.0.0/1119.96.0.1 to 19.127.255.25419.127.255.2552,097,150
15719.128.0.0/1119.128.0.1 to 19.159.255.25419.159.255.2552,097,150
15819.160.0.0/1119.160.0.1 to 19.191.255.25419.191.255.2552,097,150
15919.192.0.0/1119.192.0.1 to 19.223.255.25419.223.255.2552,097,150
16019.224.0.0/1119.224.0.1 to 19.255.255.25419.255.255.2552,097,150
16120.0.0.0/1120.0.0.1 to 20.31.255.25420.31.255.2552,097,150
16220.32.0.0/1120.32.0.1 to 20.63.255.25420.63.255.2552,097,150
16320.64.0.0/1120.64.0.1 to 20.95.255.25420.95.255.2552,097,150
16420.96.0.0/1120.96.0.1 to 20.127.255.25420.127.255.2552,097,150
16520.128.0.0/1120.128.0.1 to 20.159.255.25420.159.255.2552,097,150
16620.160.0.0/1120.160.0.1 to 20.191.255.25420.191.255.2552,097,150
16720.192.0.0/1120.192.0.1 to 20.223.255.25420.223.255.2552,097,150
16820.224.0.0/1120.224.0.1 to 20.255.255.25420.255.255.2552,097,150
16921.0.0.0/1121.0.0.1 to 21.31.255.25421.31.255.2552,097,150
17021.32.0.0/1121.32.0.1 to 21.63.255.25421.63.255.2552,097,150
17121.64.0.0/1121.64.0.1 to 21.95.255.25421.95.255.2552,097,150
17221.96.0.0/1121.96.0.1 to 21.127.255.25421.127.255.2552,097,150
17321.128.0.0/1121.128.0.1 to 21.159.255.25421.159.255.2552,097,150
17421.160.0.0/1121.160.0.1 to 21.191.255.25421.191.255.2552,097,150
17521.192.0.0/1121.192.0.1 to 21.223.255.25421.223.255.2552,097,150
17621.224.0.0/1121.224.0.1 to 21.255.255.25421.255.255.2552,097,150
17722.0.0.0/1122.0.0.1 to 22.31.255.25422.31.255.2552,097,150
17822.32.0.0/1122.32.0.1 to 22.63.255.25422.63.255.2552,097,150
17922.64.0.0/1122.64.0.1 to 22.95.255.25422.95.255.2552,097,150
18022.96.0.0/1122.96.0.1 to 22.127.255.25422.127.255.2552,097,150
18122.128.0.0/1122.128.0.1 to 22.159.255.25422.159.255.2552,097,150
18222.160.0.0/1122.160.0.1 to 22.191.255.25422.191.255.2552,097,150
18322.192.0.0/1122.192.0.1 to 22.223.255.25422.223.255.2552,097,150
18422.224.0.0/1122.224.0.1 to 22.255.255.25422.255.255.2552,097,150
18523.0.0.0/1123.0.0.1 to 23.31.255.25423.31.255.2552,097,150
18623.32.0.0/1123.32.0.1 to 23.63.255.25423.63.255.2552,097,150
18723.64.0.0/1123.64.0.1 to 23.95.255.25423.95.255.2552,097,150
18823.96.0.0/1123.96.0.1 to 23.127.255.25423.127.255.2552,097,150
18923.128.0.0/1123.128.0.1 to 23.159.255.25423.159.255.2552,097,150
19023.160.0.0/1123.160.0.1 to 23.191.255.25423.191.255.2552,097,150
19123.192.0.0/1123.192.0.1 to 23.223.255.25423.223.255.2552,097,150
19223.224.0.0/1123.224.0.1 to 23.255.255.25423.255.255.2552,097,150
19324.0.0.0/1124.0.0.1 to 24.31.255.25424.31.255.2552,097,150
19424.32.0.0/1124.32.0.1 to 24.63.255.25424.63.255.2552,097,150
19524.64.0.0/1124.64.0.1 to 24.95.255.25424.95.255.2552,097,150
19624.96.0.0/1124.96.0.1 to 24.127.255.25424.127.255.2552,097,150
19724.128.0.0/1124.128.0.1 to 24.159.255.25424.159.255.2552,097,150
19824.160.0.0/1124.160.0.1 to 24.191.255.25424.191.255.2552,097,150
19924.192.0.0/1124.192.0.1 to 24.223.255.25424.223.255.2552,097,150
20024.224.0.0/1124.224.0.1 to 24.255.255.25424.255.255.2552,097,150
20125.0.0.0/1125.0.0.1 to 25.31.255.25425.31.255.2552,097,150
20225.32.0.0/1125.32.0.1 to 25.63.255.25425.63.255.2552,097,150
20325.64.0.0/1125.64.0.1 to 25.95.255.25425.95.255.2552,097,150
20425.96.0.0/1125.96.0.1 to 25.127.255.25425.127.255.2552,097,150
20525.128.0.0/1125.128.0.1 to 25.159.255.25425.159.255.2552,097,150
20625.160.0.0/1125.160.0.1 to 25.191.255.25425.191.255.2552,097,150
20725.192.0.0/1125.192.0.1 to 25.223.255.25425.223.255.2552,097,150
20825.224.0.0/1125.224.0.1 to 25.255.255.25425.255.255.2552,097,150
20926.0.0.0/1126.0.0.1 to 26.31.255.25426.31.255.2552,097,150
21026.32.0.0/1126.32.0.1 to 26.63.255.25426.63.255.2552,097,150
21126.64.0.0/1126.64.0.1 to 26.95.255.25426.95.255.2552,097,150
21226.96.0.0/1126.96.0.1 to 26.127.255.25426.127.255.2552,097,150
21326.128.0.0/1126.128.0.1 to 26.159.255.25426.159.255.2552,097,150
21426.160.0.0/1126.160.0.1 to 26.191.255.25426.191.255.2552,097,150
21526.192.0.0/1126.192.0.1 to 26.223.255.25426.223.255.2552,097,150
21626.224.0.0/1126.224.0.1 to 26.255.255.25426.255.255.2552,097,150
21727.0.0.0/1127.0.0.1 to 27.31.255.25427.31.255.2552,097,150
21827.32.0.0/1127.32.0.1 to 27.63.255.25427.63.255.2552,097,150
21927.64.0.0/1127.64.0.1 to 27.95.255.25427.95.255.2552,097,150
22027.96.0.0/1127.96.0.1 to 27.127.255.25427.127.255.2552,097,150
22127.128.0.0/1127.128.0.1 to 27.159.255.25427.159.255.2552,097,150
22227.160.0.0/1127.160.0.1 to 27.191.255.25427.191.255.2552,097,150
22327.192.0.0/1127.192.0.1 to 27.223.255.25427.223.255.2552,097,150
22427.224.0.0/1127.224.0.1 to 27.255.255.25427.255.255.2552,097,150
22528.0.0.0/1128.0.0.1 to 28.31.255.25428.31.255.2552,097,150
22628.32.0.0/1128.32.0.1 to 28.63.255.25428.63.255.2552,097,150
22728.64.0.0/1128.64.0.1 to 28.95.255.25428.95.255.2552,097,150
22828.96.0.0/1128.96.0.1 to 28.127.255.25428.127.255.2552,097,150
22928.128.0.0/1128.128.0.1 to 28.159.255.25428.159.255.2552,097,150
23028.160.0.0/1128.160.0.1 to 28.191.255.25428.191.255.2552,097,150
23128.192.0.0/1128.192.0.1 to 28.223.255.25428.223.255.2552,097,150
23228.224.0.0/1128.224.0.1 to 28.255.255.25428.255.255.2552,097,150
23329.0.0.0/1129.0.0.1 to 29.31.255.25429.31.255.2552,097,150
23429.32.0.0/1129.32.0.1 to 29.63.255.25429.63.255.2552,097,150
23529.64.0.0/1129.64.0.1 to 29.95.255.25429.95.255.2552,097,150
23629.96.0.0/1129.96.0.1 to 29.127.255.25429.127.255.2552,097,150
23729.128.0.0/1129.128.0.1 to 29.159.255.25429.159.255.2552,097,150
23829.160.0.0/1129.160.0.1 to 29.191.255.25429.191.255.2552,097,150
23929.192.0.0/1129.192.0.1 to 29.223.255.25429.223.255.2552,097,150
24029.224.0.0/1129.224.0.1 to 29.255.255.25429.255.255.2552,097,150
24130.0.0.0/1130.0.0.1 to 30.31.255.25430.31.255.2552,097,150
24230.32.0.0/1130.32.0.1 to 30.63.255.25430.63.255.2552,097,150
24330.64.0.0/1130.64.0.1 to 30.95.255.25430.95.255.2552,097,150
24430.96.0.0/1130.96.0.1 to 30.127.255.25430.127.255.2552,097,150
24530.128.0.0/1130.128.0.1 to 30.159.255.25430.159.255.2552,097,150
24630.160.0.0/1130.160.0.1 to 30.191.255.25430.191.255.2552,097,150
24730.192.0.0/1130.192.0.1 to 30.223.255.25430.223.255.2552,097,150
24830.224.0.0/1130.224.0.1 to 30.255.255.25430.255.255.2552,097,150
24931.0.0.0/1131.0.0.1 to 31.31.255.25431.31.255.2552,097,150
25031.32.0.0/1131.32.0.1 to 31.63.255.25431.63.255.2552,097,150
25131.64.0.0/1131.64.0.1 to 31.95.255.25431.95.255.2552,097,150
25231.96.0.0/1131.96.0.1 to 31.127.255.25431.127.255.2552,097,150
25331.128.0.0/1131.128.0.1 to 31.159.255.25431.159.255.2552,097,150
25431.160.0.0/1131.160.0.1 to 31.191.255.25431.191.255.2552,097,150
25531.192.0.0/1131.192.0.1 to 31.223.255.25431.223.255.2552,097,150
25631.224.0.0/1131.224.0.1 to 31.255.255.25431.255.255.2552,097,150

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.