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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.

Network136.2.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
136.2.0.0
Broadcast address
136.3.255.255
First usable
136.2.0.1
Last usable
136.3.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
B (default /16)
As numbers
Hex 88020000 · Integer 2281832448 to 2281963519
Reverse DNS zones
2.136.in-addr.arpa
3.136.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10001000.00000010.00000000.00000000136.2.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network10001000.00000010.00000000.00000000136.2.0.0
Broadcast10001000.00000011.11111111.11111111136.3.255.255
Split into smaller subnets/23
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

136.2.0.0/15 makes 256 subnets of /23.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1136.2.0.0/23136.2.0.1 to 136.2.1.254136.2.1.255510
2136.2.2.0/23136.2.2.1 to 136.2.3.254136.2.3.255510
3136.2.4.0/23136.2.4.1 to 136.2.5.254136.2.5.255510
4136.2.6.0/23136.2.6.1 to 136.2.7.254136.2.7.255510
5136.2.8.0/23136.2.8.1 to 136.2.9.254136.2.9.255510
6136.2.10.0/23136.2.10.1 to 136.2.11.254136.2.11.255510
7136.2.12.0/23136.2.12.1 to 136.2.13.254136.2.13.255510
8136.2.14.0/23136.2.14.1 to 136.2.15.254136.2.15.255510
9136.2.16.0/23136.2.16.1 to 136.2.17.254136.2.17.255510
10136.2.18.0/23136.2.18.1 to 136.2.19.254136.2.19.255510
11136.2.20.0/23136.2.20.1 to 136.2.21.254136.2.21.255510
12136.2.22.0/23136.2.22.1 to 136.2.23.254136.2.23.255510
13136.2.24.0/23136.2.24.1 to 136.2.25.254136.2.25.255510
14136.2.26.0/23136.2.26.1 to 136.2.27.254136.2.27.255510
15136.2.28.0/23136.2.28.1 to 136.2.29.254136.2.29.255510
16136.2.30.0/23136.2.30.1 to 136.2.31.254136.2.31.255510
17136.2.32.0/23136.2.32.1 to 136.2.33.254136.2.33.255510
18136.2.34.0/23136.2.34.1 to 136.2.35.254136.2.35.255510
19136.2.36.0/23136.2.36.1 to 136.2.37.254136.2.37.255510
20136.2.38.0/23136.2.38.1 to 136.2.39.254136.2.39.255510
21136.2.40.0/23136.2.40.1 to 136.2.41.254136.2.41.255510
22136.2.42.0/23136.2.42.1 to 136.2.43.254136.2.43.255510
23136.2.44.0/23136.2.44.1 to 136.2.45.254136.2.45.255510
24136.2.46.0/23136.2.46.1 to 136.2.47.254136.2.47.255510
25136.2.48.0/23136.2.48.1 to 136.2.49.254136.2.49.255510
26136.2.50.0/23136.2.50.1 to 136.2.51.254136.2.51.255510
27136.2.52.0/23136.2.52.1 to 136.2.53.254136.2.53.255510
28136.2.54.0/23136.2.54.1 to 136.2.55.254136.2.55.255510
29136.2.56.0/23136.2.56.1 to 136.2.57.254136.2.57.255510
30136.2.58.0/23136.2.58.1 to 136.2.59.254136.2.59.255510
31136.2.60.0/23136.2.60.1 to 136.2.61.254136.2.61.255510
32136.2.62.0/23136.2.62.1 to 136.2.63.254136.2.63.255510
33136.2.64.0/23136.2.64.1 to 136.2.65.254136.2.65.255510
34136.2.66.0/23136.2.66.1 to 136.2.67.254136.2.67.255510
35136.2.68.0/23136.2.68.1 to 136.2.69.254136.2.69.255510
36136.2.70.0/23136.2.70.1 to 136.2.71.254136.2.71.255510
37136.2.72.0/23136.2.72.1 to 136.2.73.254136.2.73.255510
38136.2.74.0/23136.2.74.1 to 136.2.75.254136.2.75.255510
39136.2.76.0/23136.2.76.1 to 136.2.77.254136.2.77.255510
40136.2.78.0/23136.2.78.1 to 136.2.79.254136.2.79.255510
41136.2.80.0/23136.2.80.1 to 136.2.81.254136.2.81.255510
42136.2.82.0/23136.2.82.1 to 136.2.83.254136.2.83.255510
43136.2.84.0/23136.2.84.1 to 136.2.85.254136.2.85.255510
44136.2.86.0/23136.2.86.1 to 136.2.87.254136.2.87.255510
45136.2.88.0/23136.2.88.1 to 136.2.89.254136.2.89.255510
46136.2.90.0/23136.2.90.1 to 136.2.91.254136.2.91.255510
47136.2.92.0/23136.2.92.1 to 136.2.93.254136.2.93.255510
48136.2.94.0/23136.2.94.1 to 136.2.95.254136.2.95.255510
49136.2.96.0/23136.2.96.1 to 136.2.97.254136.2.97.255510
50136.2.98.0/23136.2.98.1 to 136.2.99.254136.2.99.255510
51136.2.100.0/23136.2.100.1 to 136.2.101.254136.2.101.255510
52136.2.102.0/23136.2.102.1 to 136.2.103.254136.2.103.255510
53136.2.104.0/23136.2.104.1 to 136.2.105.254136.2.105.255510
54136.2.106.0/23136.2.106.1 to 136.2.107.254136.2.107.255510
55136.2.108.0/23136.2.108.1 to 136.2.109.254136.2.109.255510
56136.2.110.0/23136.2.110.1 to 136.2.111.254136.2.111.255510
57136.2.112.0/23136.2.112.1 to 136.2.113.254136.2.113.255510
58136.2.114.0/23136.2.114.1 to 136.2.115.254136.2.115.255510
59136.2.116.0/23136.2.116.1 to 136.2.117.254136.2.117.255510
60136.2.118.0/23136.2.118.1 to 136.2.119.254136.2.119.255510
61136.2.120.0/23136.2.120.1 to 136.2.121.254136.2.121.255510
62136.2.122.0/23136.2.122.1 to 136.2.123.254136.2.123.255510
63136.2.124.0/23136.2.124.1 to 136.2.125.254136.2.125.255510
64136.2.126.0/23136.2.126.1 to 136.2.127.254136.2.127.255510
65136.2.128.0/23136.2.128.1 to 136.2.129.254136.2.129.255510
66136.2.130.0/23136.2.130.1 to 136.2.131.254136.2.131.255510
67136.2.132.0/23136.2.132.1 to 136.2.133.254136.2.133.255510
68136.2.134.0/23136.2.134.1 to 136.2.135.254136.2.135.255510
69136.2.136.0/23136.2.136.1 to 136.2.137.254136.2.137.255510
70136.2.138.0/23136.2.138.1 to 136.2.139.254136.2.139.255510
71136.2.140.0/23136.2.140.1 to 136.2.141.254136.2.141.255510
72136.2.142.0/23136.2.142.1 to 136.2.143.254136.2.143.255510
73136.2.144.0/23136.2.144.1 to 136.2.145.254136.2.145.255510
74136.2.146.0/23136.2.146.1 to 136.2.147.254136.2.147.255510
75136.2.148.0/23136.2.148.1 to 136.2.149.254136.2.149.255510
76136.2.150.0/23136.2.150.1 to 136.2.151.254136.2.151.255510
77136.2.152.0/23136.2.152.1 to 136.2.153.254136.2.153.255510
78136.2.154.0/23136.2.154.1 to 136.2.155.254136.2.155.255510
79136.2.156.0/23136.2.156.1 to 136.2.157.254136.2.157.255510
80136.2.158.0/23136.2.158.1 to 136.2.159.254136.2.159.255510
81136.2.160.0/23136.2.160.1 to 136.2.161.254136.2.161.255510
82136.2.162.0/23136.2.162.1 to 136.2.163.254136.2.163.255510
83136.2.164.0/23136.2.164.1 to 136.2.165.254136.2.165.255510
84136.2.166.0/23136.2.166.1 to 136.2.167.254136.2.167.255510
85136.2.168.0/23136.2.168.1 to 136.2.169.254136.2.169.255510
86136.2.170.0/23136.2.170.1 to 136.2.171.254136.2.171.255510
87136.2.172.0/23136.2.172.1 to 136.2.173.254136.2.173.255510
88136.2.174.0/23136.2.174.1 to 136.2.175.254136.2.175.255510
89136.2.176.0/23136.2.176.1 to 136.2.177.254136.2.177.255510
90136.2.178.0/23136.2.178.1 to 136.2.179.254136.2.179.255510
91136.2.180.0/23136.2.180.1 to 136.2.181.254136.2.181.255510
92136.2.182.0/23136.2.182.1 to 136.2.183.254136.2.183.255510
93136.2.184.0/23136.2.184.1 to 136.2.185.254136.2.185.255510
94136.2.186.0/23136.2.186.1 to 136.2.187.254136.2.187.255510
95136.2.188.0/23136.2.188.1 to 136.2.189.254136.2.189.255510
96136.2.190.0/23136.2.190.1 to 136.2.191.254136.2.191.255510
97136.2.192.0/23136.2.192.1 to 136.2.193.254136.2.193.255510
98136.2.194.0/23136.2.194.1 to 136.2.195.254136.2.195.255510
99136.2.196.0/23136.2.196.1 to 136.2.197.254136.2.197.255510
100136.2.198.0/23136.2.198.1 to 136.2.199.254136.2.199.255510
101136.2.200.0/23136.2.200.1 to 136.2.201.254136.2.201.255510
102136.2.202.0/23136.2.202.1 to 136.2.203.254136.2.203.255510
103136.2.204.0/23136.2.204.1 to 136.2.205.254136.2.205.255510
104136.2.206.0/23136.2.206.1 to 136.2.207.254136.2.207.255510
105136.2.208.0/23136.2.208.1 to 136.2.209.254136.2.209.255510
106136.2.210.0/23136.2.210.1 to 136.2.211.254136.2.211.255510
107136.2.212.0/23136.2.212.1 to 136.2.213.254136.2.213.255510
108136.2.214.0/23136.2.214.1 to 136.2.215.254136.2.215.255510
109136.2.216.0/23136.2.216.1 to 136.2.217.254136.2.217.255510
110136.2.218.0/23136.2.218.1 to 136.2.219.254136.2.219.255510
111136.2.220.0/23136.2.220.1 to 136.2.221.254136.2.221.255510
112136.2.222.0/23136.2.222.1 to 136.2.223.254136.2.223.255510
113136.2.224.0/23136.2.224.1 to 136.2.225.254136.2.225.255510
114136.2.226.0/23136.2.226.1 to 136.2.227.254136.2.227.255510
115136.2.228.0/23136.2.228.1 to 136.2.229.254136.2.229.255510
116136.2.230.0/23136.2.230.1 to 136.2.231.254136.2.231.255510
117136.2.232.0/23136.2.232.1 to 136.2.233.254136.2.233.255510
118136.2.234.0/23136.2.234.1 to 136.2.235.254136.2.235.255510
119136.2.236.0/23136.2.236.1 to 136.2.237.254136.2.237.255510
120136.2.238.0/23136.2.238.1 to 136.2.239.254136.2.239.255510
121136.2.240.0/23136.2.240.1 to 136.2.241.254136.2.241.255510
122136.2.242.0/23136.2.242.1 to 136.2.243.254136.2.243.255510
123136.2.244.0/23136.2.244.1 to 136.2.245.254136.2.245.255510
124136.2.246.0/23136.2.246.1 to 136.2.247.254136.2.247.255510
125136.2.248.0/23136.2.248.1 to 136.2.249.254136.2.249.255510
126136.2.250.0/23136.2.250.1 to 136.2.251.254136.2.251.255510
127136.2.252.0/23136.2.252.1 to 136.2.253.254136.2.253.255510
128136.2.254.0/23136.2.254.1 to 136.2.255.254136.2.255.255510
129136.3.0.0/23136.3.0.1 to 136.3.1.254136.3.1.255510
130136.3.2.0/23136.3.2.1 to 136.3.3.254136.3.3.255510
131136.3.4.0/23136.3.4.1 to 136.3.5.254136.3.5.255510
132136.3.6.0/23136.3.6.1 to 136.3.7.254136.3.7.255510
133136.3.8.0/23136.3.8.1 to 136.3.9.254136.3.9.255510
134136.3.10.0/23136.3.10.1 to 136.3.11.254136.3.11.255510
135136.3.12.0/23136.3.12.1 to 136.3.13.254136.3.13.255510
136136.3.14.0/23136.3.14.1 to 136.3.15.254136.3.15.255510
137136.3.16.0/23136.3.16.1 to 136.3.17.254136.3.17.255510
138136.3.18.0/23136.3.18.1 to 136.3.19.254136.3.19.255510
139136.3.20.0/23136.3.20.1 to 136.3.21.254136.3.21.255510
140136.3.22.0/23136.3.22.1 to 136.3.23.254136.3.23.255510
141136.3.24.0/23136.3.24.1 to 136.3.25.254136.3.25.255510
142136.3.26.0/23136.3.26.1 to 136.3.27.254136.3.27.255510
143136.3.28.0/23136.3.28.1 to 136.3.29.254136.3.29.255510
144136.3.30.0/23136.3.30.1 to 136.3.31.254136.3.31.255510
145136.3.32.0/23136.3.32.1 to 136.3.33.254136.3.33.255510
146136.3.34.0/23136.3.34.1 to 136.3.35.254136.3.35.255510
147136.3.36.0/23136.3.36.1 to 136.3.37.254136.3.37.255510
148136.3.38.0/23136.3.38.1 to 136.3.39.254136.3.39.255510
149136.3.40.0/23136.3.40.1 to 136.3.41.254136.3.41.255510
150136.3.42.0/23136.3.42.1 to 136.3.43.254136.3.43.255510
151136.3.44.0/23136.3.44.1 to 136.3.45.254136.3.45.255510
152136.3.46.0/23136.3.46.1 to 136.3.47.254136.3.47.255510
153136.3.48.0/23136.3.48.1 to 136.3.49.254136.3.49.255510
154136.3.50.0/23136.3.50.1 to 136.3.51.254136.3.51.255510
155136.3.52.0/23136.3.52.1 to 136.3.53.254136.3.53.255510
156136.3.54.0/23136.3.54.1 to 136.3.55.254136.3.55.255510
157136.3.56.0/23136.3.56.1 to 136.3.57.254136.3.57.255510
158136.3.58.0/23136.3.58.1 to 136.3.59.254136.3.59.255510
159136.3.60.0/23136.3.60.1 to 136.3.61.254136.3.61.255510
160136.3.62.0/23136.3.62.1 to 136.3.63.254136.3.63.255510
161136.3.64.0/23136.3.64.1 to 136.3.65.254136.3.65.255510
162136.3.66.0/23136.3.66.1 to 136.3.67.254136.3.67.255510
163136.3.68.0/23136.3.68.1 to 136.3.69.254136.3.69.255510
164136.3.70.0/23136.3.70.1 to 136.3.71.254136.3.71.255510
165136.3.72.0/23136.3.72.1 to 136.3.73.254136.3.73.255510
166136.3.74.0/23136.3.74.1 to 136.3.75.254136.3.75.255510
167136.3.76.0/23136.3.76.1 to 136.3.77.254136.3.77.255510
168136.3.78.0/23136.3.78.1 to 136.3.79.254136.3.79.255510
169136.3.80.0/23136.3.80.1 to 136.3.81.254136.3.81.255510
170136.3.82.0/23136.3.82.1 to 136.3.83.254136.3.83.255510
171136.3.84.0/23136.3.84.1 to 136.3.85.254136.3.85.255510
172136.3.86.0/23136.3.86.1 to 136.3.87.254136.3.87.255510
173136.3.88.0/23136.3.88.1 to 136.3.89.254136.3.89.255510
174136.3.90.0/23136.3.90.1 to 136.3.91.254136.3.91.255510
175136.3.92.0/23136.3.92.1 to 136.3.93.254136.3.93.255510
176136.3.94.0/23136.3.94.1 to 136.3.95.254136.3.95.255510
177136.3.96.0/23136.3.96.1 to 136.3.97.254136.3.97.255510
178136.3.98.0/23136.3.98.1 to 136.3.99.254136.3.99.255510
179136.3.100.0/23136.3.100.1 to 136.3.101.254136.3.101.255510
180136.3.102.0/23136.3.102.1 to 136.3.103.254136.3.103.255510
181136.3.104.0/23136.3.104.1 to 136.3.105.254136.3.105.255510
182136.3.106.0/23136.3.106.1 to 136.3.107.254136.3.107.255510
183136.3.108.0/23136.3.108.1 to 136.3.109.254136.3.109.255510
184136.3.110.0/23136.3.110.1 to 136.3.111.254136.3.111.255510
185136.3.112.0/23136.3.112.1 to 136.3.113.254136.3.113.255510
186136.3.114.0/23136.3.114.1 to 136.3.115.254136.3.115.255510
187136.3.116.0/23136.3.116.1 to 136.3.117.254136.3.117.255510
188136.3.118.0/23136.3.118.1 to 136.3.119.254136.3.119.255510
189136.3.120.0/23136.3.120.1 to 136.3.121.254136.3.121.255510
190136.3.122.0/23136.3.122.1 to 136.3.123.254136.3.123.255510
191136.3.124.0/23136.3.124.1 to 136.3.125.254136.3.125.255510
192136.3.126.0/23136.3.126.1 to 136.3.127.254136.3.127.255510
193136.3.128.0/23136.3.128.1 to 136.3.129.254136.3.129.255510
194136.3.130.0/23136.3.130.1 to 136.3.131.254136.3.131.255510
195136.3.132.0/23136.3.132.1 to 136.3.133.254136.3.133.255510
196136.3.134.0/23136.3.134.1 to 136.3.135.254136.3.135.255510
197136.3.136.0/23136.3.136.1 to 136.3.137.254136.3.137.255510
198136.3.138.0/23136.3.138.1 to 136.3.139.254136.3.139.255510
199136.3.140.0/23136.3.140.1 to 136.3.141.254136.3.141.255510
200136.3.142.0/23136.3.142.1 to 136.3.143.254136.3.143.255510
201136.3.144.0/23136.3.144.1 to 136.3.145.254136.3.145.255510
202136.3.146.0/23136.3.146.1 to 136.3.147.254136.3.147.255510
203136.3.148.0/23136.3.148.1 to 136.3.149.254136.3.149.255510
204136.3.150.0/23136.3.150.1 to 136.3.151.254136.3.151.255510
205136.3.152.0/23136.3.152.1 to 136.3.153.254136.3.153.255510
206136.3.154.0/23136.3.154.1 to 136.3.155.254136.3.155.255510
207136.3.156.0/23136.3.156.1 to 136.3.157.254136.3.157.255510
208136.3.158.0/23136.3.158.1 to 136.3.159.254136.3.159.255510
209136.3.160.0/23136.3.160.1 to 136.3.161.254136.3.161.255510
210136.3.162.0/23136.3.162.1 to 136.3.163.254136.3.163.255510
211136.3.164.0/23136.3.164.1 to 136.3.165.254136.3.165.255510
212136.3.166.0/23136.3.166.1 to 136.3.167.254136.3.167.255510
213136.3.168.0/23136.3.168.1 to 136.3.169.254136.3.169.255510
214136.3.170.0/23136.3.170.1 to 136.3.171.254136.3.171.255510
215136.3.172.0/23136.3.172.1 to 136.3.173.254136.3.173.255510
216136.3.174.0/23136.3.174.1 to 136.3.175.254136.3.175.255510
217136.3.176.0/23136.3.176.1 to 136.3.177.254136.3.177.255510
218136.3.178.0/23136.3.178.1 to 136.3.179.254136.3.179.255510
219136.3.180.0/23136.3.180.1 to 136.3.181.254136.3.181.255510
220136.3.182.0/23136.3.182.1 to 136.3.183.254136.3.183.255510
221136.3.184.0/23136.3.184.1 to 136.3.185.254136.3.185.255510
222136.3.186.0/23136.3.186.1 to 136.3.187.254136.3.187.255510
223136.3.188.0/23136.3.188.1 to 136.3.189.254136.3.189.255510
224136.3.190.0/23136.3.190.1 to 136.3.191.254136.3.191.255510
225136.3.192.0/23136.3.192.1 to 136.3.193.254136.3.193.255510
226136.3.194.0/23136.3.194.1 to 136.3.195.254136.3.195.255510
227136.3.196.0/23136.3.196.1 to 136.3.197.254136.3.197.255510
228136.3.198.0/23136.3.198.1 to 136.3.199.254136.3.199.255510
229136.3.200.0/23136.3.200.1 to 136.3.201.254136.3.201.255510
230136.3.202.0/23136.3.202.1 to 136.3.203.254136.3.203.255510
231136.3.204.0/23136.3.204.1 to 136.3.205.254136.3.205.255510
232136.3.206.0/23136.3.206.1 to 136.3.207.254136.3.207.255510
233136.3.208.0/23136.3.208.1 to 136.3.209.254136.3.209.255510
234136.3.210.0/23136.3.210.1 to 136.3.211.254136.3.211.255510
235136.3.212.0/23136.3.212.1 to 136.3.213.254136.3.213.255510
236136.3.214.0/23136.3.214.1 to 136.3.215.254136.3.215.255510
237136.3.216.0/23136.3.216.1 to 136.3.217.254136.3.217.255510
238136.3.218.0/23136.3.218.1 to 136.3.219.254136.3.219.255510
239136.3.220.0/23136.3.220.1 to 136.3.221.254136.3.221.255510
240136.3.222.0/23136.3.222.1 to 136.3.223.254136.3.223.255510
241136.3.224.0/23136.3.224.1 to 136.3.225.254136.3.225.255510
242136.3.226.0/23136.3.226.1 to 136.3.227.254136.3.227.255510
243136.3.228.0/23136.3.228.1 to 136.3.229.254136.3.229.255510
244136.3.230.0/23136.3.230.1 to 136.3.231.254136.3.231.255510
245136.3.232.0/23136.3.232.1 to 136.3.233.254136.3.233.255510
246136.3.234.0/23136.3.234.1 to 136.3.235.254136.3.235.255510
247136.3.236.0/23136.3.236.1 to 136.3.237.254136.3.237.255510
248136.3.238.0/23136.3.238.1 to 136.3.239.254136.3.239.255510
249136.3.240.0/23136.3.240.1 to 136.3.241.254136.3.241.255510
250136.3.242.0/23136.3.242.1 to 136.3.243.254136.3.243.255510
251136.3.244.0/23136.3.244.1 to 136.3.245.254136.3.245.255510
252136.3.246.0/23136.3.246.1 to 136.3.247.254136.3.247.255510
253136.3.248.0/23136.3.248.1 to 136.3.249.254136.3.249.255510
254136.3.250.0/23136.3.250.1 to 136.3.251.254136.3.251.255510
255136.3.252.0/23136.3.252.1 to 136.3.253.254136.3.253.255510
256136.3.254.0/23136.3.254.1 to 136.3.255.254136.3.255.255510

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.