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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.

Network104.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
104.0.0.0
Broadcast address
105.255.255.255
First usable
104.0.0.1
Last usable
105.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
A (default /8)
As numbers
Hex 68000000 · Integer 1744830464 to 1778384895
Reverse DNS zones
104.in-addr.arpa
105.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01101000.00000000.00000000.00000000104.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network01101000.00000000.00000000.00000000104.0.0.0
Broadcast01101001.11111111.11111111.11111111105.255.255.255
Split into smaller subnets/16
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

104.0.0.0/7 makes 512 subnets of /16; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1104.0.0.0/16104.0.0.1 to 104.0.255.254104.0.255.25565,534
2104.1.0.0/16104.1.0.1 to 104.1.255.254104.1.255.25565,534
3104.2.0.0/16104.2.0.1 to 104.2.255.254104.2.255.25565,534
4104.3.0.0/16104.3.0.1 to 104.3.255.254104.3.255.25565,534
5104.4.0.0/16104.4.0.1 to 104.4.255.254104.4.255.25565,534
6104.5.0.0/16104.5.0.1 to 104.5.255.254104.5.255.25565,534
7104.6.0.0/16104.6.0.1 to 104.6.255.254104.6.255.25565,534
8104.7.0.0/16104.7.0.1 to 104.7.255.254104.7.255.25565,534
9104.8.0.0/16104.8.0.1 to 104.8.255.254104.8.255.25565,534
10104.9.0.0/16104.9.0.1 to 104.9.255.254104.9.255.25565,534
11104.10.0.0/16104.10.0.1 to 104.10.255.254104.10.255.25565,534
12104.11.0.0/16104.11.0.1 to 104.11.255.254104.11.255.25565,534
13104.12.0.0/16104.12.0.1 to 104.12.255.254104.12.255.25565,534
14104.13.0.0/16104.13.0.1 to 104.13.255.254104.13.255.25565,534
15104.14.0.0/16104.14.0.1 to 104.14.255.254104.14.255.25565,534
16104.15.0.0/16104.15.0.1 to 104.15.255.254104.15.255.25565,534
17104.16.0.0/16104.16.0.1 to 104.16.255.254104.16.255.25565,534
18104.17.0.0/16104.17.0.1 to 104.17.255.254104.17.255.25565,534
19104.18.0.0/16104.18.0.1 to 104.18.255.254104.18.255.25565,534
20104.19.0.0/16104.19.0.1 to 104.19.255.254104.19.255.25565,534
21104.20.0.0/16104.20.0.1 to 104.20.255.254104.20.255.25565,534
22104.21.0.0/16104.21.0.1 to 104.21.255.254104.21.255.25565,534
23104.22.0.0/16104.22.0.1 to 104.22.255.254104.22.255.25565,534
24104.23.0.0/16104.23.0.1 to 104.23.255.254104.23.255.25565,534
25104.24.0.0/16104.24.0.1 to 104.24.255.254104.24.255.25565,534
26104.25.0.0/16104.25.0.1 to 104.25.255.254104.25.255.25565,534
27104.26.0.0/16104.26.0.1 to 104.26.255.254104.26.255.25565,534
28104.27.0.0/16104.27.0.1 to 104.27.255.254104.27.255.25565,534
29104.28.0.0/16104.28.0.1 to 104.28.255.254104.28.255.25565,534
30104.29.0.0/16104.29.0.1 to 104.29.255.254104.29.255.25565,534
31104.30.0.0/16104.30.0.1 to 104.30.255.254104.30.255.25565,534
32104.31.0.0/16104.31.0.1 to 104.31.255.254104.31.255.25565,534
33104.32.0.0/16104.32.0.1 to 104.32.255.254104.32.255.25565,534
34104.33.0.0/16104.33.0.1 to 104.33.255.254104.33.255.25565,534
35104.34.0.0/16104.34.0.1 to 104.34.255.254104.34.255.25565,534
36104.35.0.0/16104.35.0.1 to 104.35.255.254104.35.255.25565,534
37104.36.0.0/16104.36.0.1 to 104.36.255.254104.36.255.25565,534
38104.37.0.0/16104.37.0.1 to 104.37.255.254104.37.255.25565,534
39104.38.0.0/16104.38.0.1 to 104.38.255.254104.38.255.25565,534
40104.39.0.0/16104.39.0.1 to 104.39.255.254104.39.255.25565,534
41104.40.0.0/16104.40.0.1 to 104.40.255.254104.40.255.25565,534
42104.41.0.0/16104.41.0.1 to 104.41.255.254104.41.255.25565,534
43104.42.0.0/16104.42.0.1 to 104.42.255.254104.42.255.25565,534
44104.43.0.0/16104.43.0.1 to 104.43.255.254104.43.255.25565,534
45104.44.0.0/16104.44.0.1 to 104.44.255.254104.44.255.25565,534
46104.45.0.0/16104.45.0.1 to 104.45.255.254104.45.255.25565,534
47104.46.0.0/16104.46.0.1 to 104.46.255.254104.46.255.25565,534
48104.47.0.0/16104.47.0.1 to 104.47.255.254104.47.255.25565,534
49104.48.0.0/16104.48.0.1 to 104.48.255.254104.48.255.25565,534
50104.49.0.0/16104.49.0.1 to 104.49.255.254104.49.255.25565,534
51104.50.0.0/16104.50.0.1 to 104.50.255.254104.50.255.25565,534
52104.51.0.0/16104.51.0.1 to 104.51.255.254104.51.255.25565,534
53104.52.0.0/16104.52.0.1 to 104.52.255.254104.52.255.25565,534
54104.53.0.0/16104.53.0.1 to 104.53.255.254104.53.255.25565,534
55104.54.0.0/16104.54.0.1 to 104.54.255.254104.54.255.25565,534
56104.55.0.0/16104.55.0.1 to 104.55.255.254104.55.255.25565,534
57104.56.0.0/16104.56.0.1 to 104.56.255.254104.56.255.25565,534
58104.57.0.0/16104.57.0.1 to 104.57.255.254104.57.255.25565,534
59104.58.0.0/16104.58.0.1 to 104.58.255.254104.58.255.25565,534
60104.59.0.0/16104.59.0.1 to 104.59.255.254104.59.255.25565,534
61104.60.0.0/16104.60.0.1 to 104.60.255.254104.60.255.25565,534
62104.61.0.0/16104.61.0.1 to 104.61.255.254104.61.255.25565,534
63104.62.0.0/16104.62.0.1 to 104.62.255.254104.62.255.25565,534
64104.63.0.0/16104.63.0.1 to 104.63.255.254104.63.255.25565,534
65104.64.0.0/16104.64.0.1 to 104.64.255.254104.64.255.25565,534
66104.65.0.0/16104.65.0.1 to 104.65.255.254104.65.255.25565,534
67104.66.0.0/16104.66.0.1 to 104.66.255.254104.66.255.25565,534
68104.67.0.0/16104.67.0.1 to 104.67.255.254104.67.255.25565,534
69104.68.0.0/16104.68.0.1 to 104.68.255.254104.68.255.25565,534
70104.69.0.0/16104.69.0.1 to 104.69.255.254104.69.255.25565,534
71104.70.0.0/16104.70.0.1 to 104.70.255.254104.70.255.25565,534
72104.71.0.0/16104.71.0.1 to 104.71.255.254104.71.255.25565,534
73104.72.0.0/16104.72.0.1 to 104.72.255.254104.72.255.25565,534
74104.73.0.0/16104.73.0.1 to 104.73.255.254104.73.255.25565,534
75104.74.0.0/16104.74.0.1 to 104.74.255.254104.74.255.25565,534
76104.75.0.0/16104.75.0.1 to 104.75.255.254104.75.255.25565,534
77104.76.0.0/16104.76.0.1 to 104.76.255.254104.76.255.25565,534
78104.77.0.0/16104.77.0.1 to 104.77.255.254104.77.255.25565,534
79104.78.0.0/16104.78.0.1 to 104.78.255.254104.78.255.25565,534
80104.79.0.0/16104.79.0.1 to 104.79.255.254104.79.255.25565,534
81104.80.0.0/16104.80.0.1 to 104.80.255.254104.80.255.25565,534
82104.81.0.0/16104.81.0.1 to 104.81.255.254104.81.255.25565,534
83104.82.0.0/16104.82.0.1 to 104.82.255.254104.82.255.25565,534
84104.83.0.0/16104.83.0.1 to 104.83.255.254104.83.255.25565,534
85104.84.0.0/16104.84.0.1 to 104.84.255.254104.84.255.25565,534
86104.85.0.0/16104.85.0.1 to 104.85.255.254104.85.255.25565,534
87104.86.0.0/16104.86.0.1 to 104.86.255.254104.86.255.25565,534
88104.87.0.0/16104.87.0.1 to 104.87.255.254104.87.255.25565,534
89104.88.0.0/16104.88.0.1 to 104.88.255.254104.88.255.25565,534
90104.89.0.0/16104.89.0.1 to 104.89.255.254104.89.255.25565,534
91104.90.0.0/16104.90.0.1 to 104.90.255.254104.90.255.25565,534
92104.91.0.0/16104.91.0.1 to 104.91.255.254104.91.255.25565,534
93104.92.0.0/16104.92.0.1 to 104.92.255.254104.92.255.25565,534
94104.93.0.0/16104.93.0.1 to 104.93.255.254104.93.255.25565,534
95104.94.0.0/16104.94.0.1 to 104.94.255.254104.94.255.25565,534
96104.95.0.0/16104.95.0.1 to 104.95.255.254104.95.255.25565,534
97104.96.0.0/16104.96.0.1 to 104.96.255.254104.96.255.25565,534
98104.97.0.0/16104.97.0.1 to 104.97.255.254104.97.255.25565,534
99104.98.0.0/16104.98.0.1 to 104.98.255.254104.98.255.25565,534
100104.99.0.0/16104.99.0.1 to 104.99.255.254104.99.255.25565,534
101104.100.0.0/16104.100.0.1 to 104.100.255.254104.100.255.25565,534
102104.101.0.0/16104.101.0.1 to 104.101.255.254104.101.255.25565,534
103104.102.0.0/16104.102.0.1 to 104.102.255.254104.102.255.25565,534
104104.103.0.0/16104.103.0.1 to 104.103.255.254104.103.255.25565,534
105104.104.0.0/16104.104.0.1 to 104.104.255.254104.104.255.25565,534
106104.105.0.0/16104.105.0.1 to 104.105.255.254104.105.255.25565,534
107104.106.0.0/16104.106.0.1 to 104.106.255.254104.106.255.25565,534
108104.107.0.0/16104.107.0.1 to 104.107.255.254104.107.255.25565,534
109104.108.0.0/16104.108.0.1 to 104.108.255.254104.108.255.25565,534
110104.109.0.0/16104.109.0.1 to 104.109.255.254104.109.255.25565,534
111104.110.0.0/16104.110.0.1 to 104.110.255.254104.110.255.25565,534
112104.111.0.0/16104.111.0.1 to 104.111.255.254104.111.255.25565,534
113104.112.0.0/16104.112.0.1 to 104.112.255.254104.112.255.25565,534
114104.113.0.0/16104.113.0.1 to 104.113.255.254104.113.255.25565,534
115104.114.0.0/16104.114.0.1 to 104.114.255.254104.114.255.25565,534
116104.115.0.0/16104.115.0.1 to 104.115.255.254104.115.255.25565,534
117104.116.0.0/16104.116.0.1 to 104.116.255.254104.116.255.25565,534
118104.117.0.0/16104.117.0.1 to 104.117.255.254104.117.255.25565,534
119104.118.0.0/16104.118.0.1 to 104.118.255.254104.118.255.25565,534
120104.119.0.0/16104.119.0.1 to 104.119.255.254104.119.255.25565,534
121104.120.0.0/16104.120.0.1 to 104.120.255.254104.120.255.25565,534
122104.121.0.0/16104.121.0.1 to 104.121.255.254104.121.255.25565,534
123104.122.0.0/16104.122.0.1 to 104.122.255.254104.122.255.25565,534
124104.123.0.0/16104.123.0.1 to 104.123.255.254104.123.255.25565,534
125104.124.0.0/16104.124.0.1 to 104.124.255.254104.124.255.25565,534
126104.125.0.0/16104.125.0.1 to 104.125.255.254104.125.255.25565,534
127104.126.0.0/16104.126.0.1 to 104.126.255.254104.126.255.25565,534
128104.127.0.0/16104.127.0.1 to 104.127.255.254104.127.255.25565,534
129104.128.0.0/16104.128.0.1 to 104.128.255.254104.128.255.25565,534
130104.129.0.0/16104.129.0.1 to 104.129.255.254104.129.255.25565,534
131104.130.0.0/16104.130.0.1 to 104.130.255.254104.130.255.25565,534
132104.131.0.0/16104.131.0.1 to 104.131.255.254104.131.255.25565,534
133104.132.0.0/16104.132.0.1 to 104.132.255.254104.132.255.25565,534
134104.133.0.0/16104.133.0.1 to 104.133.255.254104.133.255.25565,534
135104.134.0.0/16104.134.0.1 to 104.134.255.254104.134.255.25565,534
136104.135.0.0/16104.135.0.1 to 104.135.255.254104.135.255.25565,534
137104.136.0.0/16104.136.0.1 to 104.136.255.254104.136.255.25565,534
138104.137.0.0/16104.137.0.1 to 104.137.255.254104.137.255.25565,534
139104.138.0.0/16104.138.0.1 to 104.138.255.254104.138.255.25565,534
140104.139.0.0/16104.139.0.1 to 104.139.255.254104.139.255.25565,534
141104.140.0.0/16104.140.0.1 to 104.140.255.254104.140.255.25565,534
142104.141.0.0/16104.141.0.1 to 104.141.255.254104.141.255.25565,534
143104.142.0.0/16104.142.0.1 to 104.142.255.254104.142.255.25565,534
144104.143.0.0/16104.143.0.1 to 104.143.255.254104.143.255.25565,534
145104.144.0.0/16104.144.0.1 to 104.144.255.254104.144.255.25565,534
146104.145.0.0/16104.145.0.1 to 104.145.255.254104.145.255.25565,534
147104.146.0.0/16104.146.0.1 to 104.146.255.254104.146.255.25565,534
148104.147.0.0/16104.147.0.1 to 104.147.255.254104.147.255.25565,534
149104.148.0.0/16104.148.0.1 to 104.148.255.254104.148.255.25565,534
150104.149.0.0/16104.149.0.1 to 104.149.255.254104.149.255.25565,534
151104.150.0.0/16104.150.0.1 to 104.150.255.254104.150.255.25565,534
152104.151.0.0/16104.151.0.1 to 104.151.255.254104.151.255.25565,534
153104.152.0.0/16104.152.0.1 to 104.152.255.254104.152.255.25565,534
154104.153.0.0/16104.153.0.1 to 104.153.255.254104.153.255.25565,534
155104.154.0.0/16104.154.0.1 to 104.154.255.254104.154.255.25565,534
156104.155.0.0/16104.155.0.1 to 104.155.255.254104.155.255.25565,534
157104.156.0.0/16104.156.0.1 to 104.156.255.254104.156.255.25565,534
158104.157.0.0/16104.157.0.1 to 104.157.255.254104.157.255.25565,534
159104.158.0.0/16104.158.0.1 to 104.158.255.254104.158.255.25565,534
160104.159.0.0/16104.159.0.1 to 104.159.255.254104.159.255.25565,534
161104.160.0.0/16104.160.0.1 to 104.160.255.254104.160.255.25565,534
162104.161.0.0/16104.161.0.1 to 104.161.255.254104.161.255.25565,534
163104.162.0.0/16104.162.0.1 to 104.162.255.254104.162.255.25565,534
164104.163.0.0/16104.163.0.1 to 104.163.255.254104.163.255.25565,534
165104.164.0.0/16104.164.0.1 to 104.164.255.254104.164.255.25565,534
166104.165.0.0/16104.165.0.1 to 104.165.255.254104.165.255.25565,534
167104.166.0.0/16104.166.0.1 to 104.166.255.254104.166.255.25565,534
168104.167.0.0/16104.167.0.1 to 104.167.255.254104.167.255.25565,534
169104.168.0.0/16104.168.0.1 to 104.168.255.254104.168.255.25565,534
170104.169.0.0/16104.169.0.1 to 104.169.255.254104.169.255.25565,534
171104.170.0.0/16104.170.0.1 to 104.170.255.254104.170.255.25565,534
172104.171.0.0/16104.171.0.1 to 104.171.255.254104.171.255.25565,534
173104.172.0.0/16104.172.0.1 to 104.172.255.254104.172.255.25565,534
174104.173.0.0/16104.173.0.1 to 104.173.255.254104.173.255.25565,534
175104.174.0.0/16104.174.0.1 to 104.174.255.254104.174.255.25565,534
176104.175.0.0/16104.175.0.1 to 104.175.255.254104.175.255.25565,534
177104.176.0.0/16104.176.0.1 to 104.176.255.254104.176.255.25565,534
178104.177.0.0/16104.177.0.1 to 104.177.255.254104.177.255.25565,534
179104.178.0.0/16104.178.0.1 to 104.178.255.254104.178.255.25565,534
180104.179.0.0/16104.179.0.1 to 104.179.255.254104.179.255.25565,534
181104.180.0.0/16104.180.0.1 to 104.180.255.254104.180.255.25565,534
182104.181.0.0/16104.181.0.1 to 104.181.255.254104.181.255.25565,534
183104.182.0.0/16104.182.0.1 to 104.182.255.254104.182.255.25565,534
184104.183.0.0/16104.183.0.1 to 104.183.255.254104.183.255.25565,534
185104.184.0.0/16104.184.0.1 to 104.184.255.254104.184.255.25565,534
186104.185.0.0/16104.185.0.1 to 104.185.255.254104.185.255.25565,534
187104.186.0.0/16104.186.0.1 to 104.186.255.254104.186.255.25565,534
188104.187.0.0/16104.187.0.1 to 104.187.255.254104.187.255.25565,534
189104.188.0.0/16104.188.0.1 to 104.188.255.254104.188.255.25565,534
190104.189.0.0/16104.189.0.1 to 104.189.255.254104.189.255.25565,534
191104.190.0.0/16104.190.0.1 to 104.190.255.254104.190.255.25565,534
192104.191.0.0/16104.191.0.1 to 104.191.255.254104.191.255.25565,534
193104.192.0.0/16104.192.0.1 to 104.192.255.254104.192.255.25565,534
194104.193.0.0/16104.193.0.1 to 104.193.255.254104.193.255.25565,534
195104.194.0.0/16104.194.0.1 to 104.194.255.254104.194.255.25565,534
196104.195.0.0/16104.195.0.1 to 104.195.255.254104.195.255.25565,534
197104.196.0.0/16104.196.0.1 to 104.196.255.254104.196.255.25565,534
198104.197.0.0/16104.197.0.1 to 104.197.255.254104.197.255.25565,534
199104.198.0.0/16104.198.0.1 to 104.198.255.254104.198.255.25565,534
200104.199.0.0/16104.199.0.1 to 104.199.255.254104.199.255.25565,534
201104.200.0.0/16104.200.0.1 to 104.200.255.254104.200.255.25565,534
202104.201.0.0/16104.201.0.1 to 104.201.255.254104.201.255.25565,534
203104.202.0.0/16104.202.0.1 to 104.202.255.254104.202.255.25565,534
204104.203.0.0/16104.203.0.1 to 104.203.255.254104.203.255.25565,534
205104.204.0.0/16104.204.0.1 to 104.204.255.254104.204.255.25565,534
206104.205.0.0/16104.205.0.1 to 104.205.255.254104.205.255.25565,534
207104.206.0.0/16104.206.0.1 to 104.206.255.254104.206.255.25565,534
208104.207.0.0/16104.207.0.1 to 104.207.255.254104.207.255.25565,534
209104.208.0.0/16104.208.0.1 to 104.208.255.254104.208.255.25565,534
210104.209.0.0/16104.209.0.1 to 104.209.255.254104.209.255.25565,534
211104.210.0.0/16104.210.0.1 to 104.210.255.254104.210.255.25565,534
212104.211.0.0/16104.211.0.1 to 104.211.255.254104.211.255.25565,534
213104.212.0.0/16104.212.0.1 to 104.212.255.254104.212.255.25565,534
214104.213.0.0/16104.213.0.1 to 104.213.255.254104.213.255.25565,534
215104.214.0.0/16104.214.0.1 to 104.214.255.254104.214.255.25565,534
216104.215.0.0/16104.215.0.1 to 104.215.255.254104.215.255.25565,534
217104.216.0.0/16104.216.0.1 to 104.216.255.254104.216.255.25565,534
218104.217.0.0/16104.217.0.1 to 104.217.255.254104.217.255.25565,534
219104.218.0.0/16104.218.0.1 to 104.218.255.254104.218.255.25565,534
220104.219.0.0/16104.219.0.1 to 104.219.255.254104.219.255.25565,534
221104.220.0.0/16104.220.0.1 to 104.220.255.254104.220.255.25565,534
222104.221.0.0/16104.221.0.1 to 104.221.255.254104.221.255.25565,534
223104.222.0.0/16104.222.0.1 to 104.222.255.254104.222.255.25565,534
224104.223.0.0/16104.223.0.1 to 104.223.255.254104.223.255.25565,534
225104.224.0.0/16104.224.0.1 to 104.224.255.254104.224.255.25565,534
226104.225.0.0/16104.225.0.1 to 104.225.255.254104.225.255.25565,534
227104.226.0.0/16104.226.0.1 to 104.226.255.254104.226.255.25565,534
228104.227.0.0/16104.227.0.1 to 104.227.255.254104.227.255.25565,534
229104.228.0.0/16104.228.0.1 to 104.228.255.254104.228.255.25565,534
230104.229.0.0/16104.229.0.1 to 104.229.255.254104.229.255.25565,534
231104.230.0.0/16104.230.0.1 to 104.230.255.254104.230.255.25565,534
232104.231.0.0/16104.231.0.1 to 104.231.255.254104.231.255.25565,534
233104.232.0.0/16104.232.0.1 to 104.232.255.254104.232.255.25565,534
234104.233.0.0/16104.233.0.1 to 104.233.255.254104.233.255.25565,534
235104.234.0.0/16104.234.0.1 to 104.234.255.254104.234.255.25565,534
236104.235.0.0/16104.235.0.1 to 104.235.255.254104.235.255.25565,534
237104.236.0.0/16104.236.0.1 to 104.236.255.254104.236.255.25565,534
238104.237.0.0/16104.237.0.1 to 104.237.255.254104.237.255.25565,534
239104.238.0.0/16104.238.0.1 to 104.238.255.254104.238.255.25565,534
240104.239.0.0/16104.239.0.1 to 104.239.255.254104.239.255.25565,534
241104.240.0.0/16104.240.0.1 to 104.240.255.254104.240.255.25565,534
242104.241.0.0/16104.241.0.1 to 104.241.255.254104.241.255.25565,534
243104.242.0.0/16104.242.0.1 to 104.242.255.254104.242.255.25565,534
244104.243.0.0/16104.243.0.1 to 104.243.255.254104.243.255.25565,534
245104.244.0.0/16104.244.0.1 to 104.244.255.254104.244.255.25565,534
246104.245.0.0/16104.245.0.1 to 104.245.255.254104.245.255.25565,534
247104.246.0.0/16104.246.0.1 to 104.246.255.254104.246.255.25565,534
248104.247.0.0/16104.247.0.1 to 104.247.255.254104.247.255.25565,534
249104.248.0.0/16104.248.0.1 to 104.248.255.254104.248.255.25565,534
250104.249.0.0/16104.249.0.1 to 104.249.255.254104.249.255.25565,534
251104.250.0.0/16104.250.0.1 to 104.250.255.254104.250.255.25565,534
252104.251.0.0/16104.251.0.1 to 104.251.255.254104.251.255.25565,534
253104.252.0.0/16104.252.0.1 to 104.252.255.254104.252.255.25565,534
254104.253.0.0/16104.253.0.1 to 104.253.255.254104.253.255.25565,534
255104.254.0.0/16104.254.0.1 to 104.254.255.254104.254.255.25565,534
256104.255.0.0/16104.255.0.1 to 104.255.255.254104.255.255.25565,534

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.