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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.

Network180.136.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
180.136.0.0
Broadcast address
180.137.255.255
First usable
180.136.0.1
Last usable
180.137.255.254
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 B4880000 · Integer 3028811776 to 3028942847
Reverse DNS zones
136.180.in-addr.arpa
137.180.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
Address10110100.10001000.00000000.00000000180.136.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network10110100.10001000.00000000.00000000180.136.0.0
Broadcast10110100.10001001.11111111.11111111180.137.255.255
Split into smaller subnets/24
/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)

180.136.0.0/15 makes 512 subnets of /24; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1180.136.0.0/24180.136.0.1 to 180.136.0.254180.136.0.255254
2180.136.1.0/24180.136.1.1 to 180.136.1.254180.136.1.255254
3180.136.2.0/24180.136.2.1 to 180.136.2.254180.136.2.255254
4180.136.3.0/24180.136.3.1 to 180.136.3.254180.136.3.255254
5180.136.4.0/24180.136.4.1 to 180.136.4.254180.136.4.255254
6180.136.5.0/24180.136.5.1 to 180.136.5.254180.136.5.255254
7180.136.6.0/24180.136.6.1 to 180.136.6.254180.136.6.255254
8180.136.7.0/24180.136.7.1 to 180.136.7.254180.136.7.255254
9180.136.8.0/24180.136.8.1 to 180.136.8.254180.136.8.255254
10180.136.9.0/24180.136.9.1 to 180.136.9.254180.136.9.255254
11180.136.10.0/24180.136.10.1 to 180.136.10.254180.136.10.255254
12180.136.11.0/24180.136.11.1 to 180.136.11.254180.136.11.255254
13180.136.12.0/24180.136.12.1 to 180.136.12.254180.136.12.255254
14180.136.13.0/24180.136.13.1 to 180.136.13.254180.136.13.255254
15180.136.14.0/24180.136.14.1 to 180.136.14.254180.136.14.255254
16180.136.15.0/24180.136.15.1 to 180.136.15.254180.136.15.255254
17180.136.16.0/24180.136.16.1 to 180.136.16.254180.136.16.255254
18180.136.17.0/24180.136.17.1 to 180.136.17.254180.136.17.255254
19180.136.18.0/24180.136.18.1 to 180.136.18.254180.136.18.255254
20180.136.19.0/24180.136.19.1 to 180.136.19.254180.136.19.255254
21180.136.20.0/24180.136.20.1 to 180.136.20.254180.136.20.255254
22180.136.21.0/24180.136.21.1 to 180.136.21.254180.136.21.255254
23180.136.22.0/24180.136.22.1 to 180.136.22.254180.136.22.255254
24180.136.23.0/24180.136.23.1 to 180.136.23.254180.136.23.255254
25180.136.24.0/24180.136.24.1 to 180.136.24.254180.136.24.255254
26180.136.25.0/24180.136.25.1 to 180.136.25.254180.136.25.255254
27180.136.26.0/24180.136.26.1 to 180.136.26.254180.136.26.255254
28180.136.27.0/24180.136.27.1 to 180.136.27.254180.136.27.255254
29180.136.28.0/24180.136.28.1 to 180.136.28.254180.136.28.255254
30180.136.29.0/24180.136.29.1 to 180.136.29.254180.136.29.255254
31180.136.30.0/24180.136.30.1 to 180.136.30.254180.136.30.255254
32180.136.31.0/24180.136.31.1 to 180.136.31.254180.136.31.255254
33180.136.32.0/24180.136.32.1 to 180.136.32.254180.136.32.255254
34180.136.33.0/24180.136.33.1 to 180.136.33.254180.136.33.255254
35180.136.34.0/24180.136.34.1 to 180.136.34.254180.136.34.255254
36180.136.35.0/24180.136.35.1 to 180.136.35.254180.136.35.255254
37180.136.36.0/24180.136.36.1 to 180.136.36.254180.136.36.255254
38180.136.37.0/24180.136.37.1 to 180.136.37.254180.136.37.255254
39180.136.38.0/24180.136.38.1 to 180.136.38.254180.136.38.255254
40180.136.39.0/24180.136.39.1 to 180.136.39.254180.136.39.255254
41180.136.40.0/24180.136.40.1 to 180.136.40.254180.136.40.255254
42180.136.41.0/24180.136.41.1 to 180.136.41.254180.136.41.255254
43180.136.42.0/24180.136.42.1 to 180.136.42.254180.136.42.255254
44180.136.43.0/24180.136.43.1 to 180.136.43.254180.136.43.255254
45180.136.44.0/24180.136.44.1 to 180.136.44.254180.136.44.255254
46180.136.45.0/24180.136.45.1 to 180.136.45.254180.136.45.255254
47180.136.46.0/24180.136.46.1 to 180.136.46.254180.136.46.255254
48180.136.47.0/24180.136.47.1 to 180.136.47.254180.136.47.255254
49180.136.48.0/24180.136.48.1 to 180.136.48.254180.136.48.255254
50180.136.49.0/24180.136.49.1 to 180.136.49.254180.136.49.255254
51180.136.50.0/24180.136.50.1 to 180.136.50.254180.136.50.255254
52180.136.51.0/24180.136.51.1 to 180.136.51.254180.136.51.255254
53180.136.52.0/24180.136.52.1 to 180.136.52.254180.136.52.255254
54180.136.53.0/24180.136.53.1 to 180.136.53.254180.136.53.255254
55180.136.54.0/24180.136.54.1 to 180.136.54.254180.136.54.255254
56180.136.55.0/24180.136.55.1 to 180.136.55.254180.136.55.255254
57180.136.56.0/24180.136.56.1 to 180.136.56.254180.136.56.255254
58180.136.57.0/24180.136.57.1 to 180.136.57.254180.136.57.255254
59180.136.58.0/24180.136.58.1 to 180.136.58.254180.136.58.255254
60180.136.59.0/24180.136.59.1 to 180.136.59.254180.136.59.255254
61180.136.60.0/24180.136.60.1 to 180.136.60.254180.136.60.255254
62180.136.61.0/24180.136.61.1 to 180.136.61.254180.136.61.255254
63180.136.62.0/24180.136.62.1 to 180.136.62.254180.136.62.255254
64180.136.63.0/24180.136.63.1 to 180.136.63.254180.136.63.255254
65180.136.64.0/24180.136.64.1 to 180.136.64.254180.136.64.255254
66180.136.65.0/24180.136.65.1 to 180.136.65.254180.136.65.255254
67180.136.66.0/24180.136.66.1 to 180.136.66.254180.136.66.255254
68180.136.67.0/24180.136.67.1 to 180.136.67.254180.136.67.255254
69180.136.68.0/24180.136.68.1 to 180.136.68.254180.136.68.255254
70180.136.69.0/24180.136.69.1 to 180.136.69.254180.136.69.255254
71180.136.70.0/24180.136.70.1 to 180.136.70.254180.136.70.255254
72180.136.71.0/24180.136.71.1 to 180.136.71.254180.136.71.255254
73180.136.72.0/24180.136.72.1 to 180.136.72.254180.136.72.255254
74180.136.73.0/24180.136.73.1 to 180.136.73.254180.136.73.255254
75180.136.74.0/24180.136.74.1 to 180.136.74.254180.136.74.255254
76180.136.75.0/24180.136.75.1 to 180.136.75.254180.136.75.255254
77180.136.76.0/24180.136.76.1 to 180.136.76.254180.136.76.255254
78180.136.77.0/24180.136.77.1 to 180.136.77.254180.136.77.255254
79180.136.78.0/24180.136.78.1 to 180.136.78.254180.136.78.255254
80180.136.79.0/24180.136.79.1 to 180.136.79.254180.136.79.255254
81180.136.80.0/24180.136.80.1 to 180.136.80.254180.136.80.255254
82180.136.81.0/24180.136.81.1 to 180.136.81.254180.136.81.255254
83180.136.82.0/24180.136.82.1 to 180.136.82.254180.136.82.255254
84180.136.83.0/24180.136.83.1 to 180.136.83.254180.136.83.255254
85180.136.84.0/24180.136.84.1 to 180.136.84.254180.136.84.255254
86180.136.85.0/24180.136.85.1 to 180.136.85.254180.136.85.255254
87180.136.86.0/24180.136.86.1 to 180.136.86.254180.136.86.255254
88180.136.87.0/24180.136.87.1 to 180.136.87.254180.136.87.255254
89180.136.88.0/24180.136.88.1 to 180.136.88.254180.136.88.255254
90180.136.89.0/24180.136.89.1 to 180.136.89.254180.136.89.255254
91180.136.90.0/24180.136.90.1 to 180.136.90.254180.136.90.255254
92180.136.91.0/24180.136.91.1 to 180.136.91.254180.136.91.255254
93180.136.92.0/24180.136.92.1 to 180.136.92.254180.136.92.255254
94180.136.93.0/24180.136.93.1 to 180.136.93.254180.136.93.255254
95180.136.94.0/24180.136.94.1 to 180.136.94.254180.136.94.255254
96180.136.95.0/24180.136.95.1 to 180.136.95.254180.136.95.255254
97180.136.96.0/24180.136.96.1 to 180.136.96.254180.136.96.255254
98180.136.97.0/24180.136.97.1 to 180.136.97.254180.136.97.255254
99180.136.98.0/24180.136.98.1 to 180.136.98.254180.136.98.255254
100180.136.99.0/24180.136.99.1 to 180.136.99.254180.136.99.255254
101180.136.100.0/24180.136.100.1 to 180.136.100.254180.136.100.255254
102180.136.101.0/24180.136.101.1 to 180.136.101.254180.136.101.255254
103180.136.102.0/24180.136.102.1 to 180.136.102.254180.136.102.255254
104180.136.103.0/24180.136.103.1 to 180.136.103.254180.136.103.255254
105180.136.104.0/24180.136.104.1 to 180.136.104.254180.136.104.255254
106180.136.105.0/24180.136.105.1 to 180.136.105.254180.136.105.255254
107180.136.106.0/24180.136.106.1 to 180.136.106.254180.136.106.255254
108180.136.107.0/24180.136.107.1 to 180.136.107.254180.136.107.255254
109180.136.108.0/24180.136.108.1 to 180.136.108.254180.136.108.255254
110180.136.109.0/24180.136.109.1 to 180.136.109.254180.136.109.255254
111180.136.110.0/24180.136.110.1 to 180.136.110.254180.136.110.255254
112180.136.111.0/24180.136.111.1 to 180.136.111.254180.136.111.255254
113180.136.112.0/24180.136.112.1 to 180.136.112.254180.136.112.255254
114180.136.113.0/24180.136.113.1 to 180.136.113.254180.136.113.255254
115180.136.114.0/24180.136.114.1 to 180.136.114.254180.136.114.255254
116180.136.115.0/24180.136.115.1 to 180.136.115.254180.136.115.255254
117180.136.116.0/24180.136.116.1 to 180.136.116.254180.136.116.255254
118180.136.117.0/24180.136.117.1 to 180.136.117.254180.136.117.255254
119180.136.118.0/24180.136.118.1 to 180.136.118.254180.136.118.255254
120180.136.119.0/24180.136.119.1 to 180.136.119.254180.136.119.255254
121180.136.120.0/24180.136.120.1 to 180.136.120.254180.136.120.255254
122180.136.121.0/24180.136.121.1 to 180.136.121.254180.136.121.255254
123180.136.122.0/24180.136.122.1 to 180.136.122.254180.136.122.255254
124180.136.123.0/24180.136.123.1 to 180.136.123.254180.136.123.255254
125180.136.124.0/24180.136.124.1 to 180.136.124.254180.136.124.255254
126180.136.125.0/24180.136.125.1 to 180.136.125.254180.136.125.255254
127180.136.126.0/24180.136.126.1 to 180.136.126.254180.136.126.255254
128180.136.127.0/24180.136.127.1 to 180.136.127.254180.136.127.255254
129180.136.128.0/24180.136.128.1 to 180.136.128.254180.136.128.255254
130180.136.129.0/24180.136.129.1 to 180.136.129.254180.136.129.255254
131180.136.130.0/24180.136.130.1 to 180.136.130.254180.136.130.255254
132180.136.131.0/24180.136.131.1 to 180.136.131.254180.136.131.255254
133180.136.132.0/24180.136.132.1 to 180.136.132.254180.136.132.255254
134180.136.133.0/24180.136.133.1 to 180.136.133.254180.136.133.255254
135180.136.134.0/24180.136.134.1 to 180.136.134.254180.136.134.255254
136180.136.135.0/24180.136.135.1 to 180.136.135.254180.136.135.255254
137180.136.136.0/24180.136.136.1 to 180.136.136.254180.136.136.255254
138180.136.137.0/24180.136.137.1 to 180.136.137.254180.136.137.255254
139180.136.138.0/24180.136.138.1 to 180.136.138.254180.136.138.255254
140180.136.139.0/24180.136.139.1 to 180.136.139.254180.136.139.255254
141180.136.140.0/24180.136.140.1 to 180.136.140.254180.136.140.255254
142180.136.141.0/24180.136.141.1 to 180.136.141.254180.136.141.255254
143180.136.142.0/24180.136.142.1 to 180.136.142.254180.136.142.255254
144180.136.143.0/24180.136.143.1 to 180.136.143.254180.136.143.255254
145180.136.144.0/24180.136.144.1 to 180.136.144.254180.136.144.255254
146180.136.145.0/24180.136.145.1 to 180.136.145.254180.136.145.255254
147180.136.146.0/24180.136.146.1 to 180.136.146.254180.136.146.255254
148180.136.147.0/24180.136.147.1 to 180.136.147.254180.136.147.255254
149180.136.148.0/24180.136.148.1 to 180.136.148.254180.136.148.255254
150180.136.149.0/24180.136.149.1 to 180.136.149.254180.136.149.255254
151180.136.150.0/24180.136.150.1 to 180.136.150.254180.136.150.255254
152180.136.151.0/24180.136.151.1 to 180.136.151.254180.136.151.255254
153180.136.152.0/24180.136.152.1 to 180.136.152.254180.136.152.255254
154180.136.153.0/24180.136.153.1 to 180.136.153.254180.136.153.255254
155180.136.154.0/24180.136.154.1 to 180.136.154.254180.136.154.255254
156180.136.155.0/24180.136.155.1 to 180.136.155.254180.136.155.255254
157180.136.156.0/24180.136.156.1 to 180.136.156.254180.136.156.255254
158180.136.157.0/24180.136.157.1 to 180.136.157.254180.136.157.255254
159180.136.158.0/24180.136.158.1 to 180.136.158.254180.136.158.255254
160180.136.159.0/24180.136.159.1 to 180.136.159.254180.136.159.255254
161180.136.160.0/24180.136.160.1 to 180.136.160.254180.136.160.255254
162180.136.161.0/24180.136.161.1 to 180.136.161.254180.136.161.255254
163180.136.162.0/24180.136.162.1 to 180.136.162.254180.136.162.255254
164180.136.163.0/24180.136.163.1 to 180.136.163.254180.136.163.255254
165180.136.164.0/24180.136.164.1 to 180.136.164.254180.136.164.255254
166180.136.165.0/24180.136.165.1 to 180.136.165.254180.136.165.255254
167180.136.166.0/24180.136.166.1 to 180.136.166.254180.136.166.255254
168180.136.167.0/24180.136.167.1 to 180.136.167.254180.136.167.255254
169180.136.168.0/24180.136.168.1 to 180.136.168.254180.136.168.255254
170180.136.169.0/24180.136.169.1 to 180.136.169.254180.136.169.255254
171180.136.170.0/24180.136.170.1 to 180.136.170.254180.136.170.255254
172180.136.171.0/24180.136.171.1 to 180.136.171.254180.136.171.255254
173180.136.172.0/24180.136.172.1 to 180.136.172.254180.136.172.255254
174180.136.173.0/24180.136.173.1 to 180.136.173.254180.136.173.255254
175180.136.174.0/24180.136.174.1 to 180.136.174.254180.136.174.255254
176180.136.175.0/24180.136.175.1 to 180.136.175.254180.136.175.255254
177180.136.176.0/24180.136.176.1 to 180.136.176.254180.136.176.255254
178180.136.177.0/24180.136.177.1 to 180.136.177.254180.136.177.255254
179180.136.178.0/24180.136.178.1 to 180.136.178.254180.136.178.255254
180180.136.179.0/24180.136.179.1 to 180.136.179.254180.136.179.255254
181180.136.180.0/24180.136.180.1 to 180.136.180.254180.136.180.255254
182180.136.181.0/24180.136.181.1 to 180.136.181.254180.136.181.255254
183180.136.182.0/24180.136.182.1 to 180.136.182.254180.136.182.255254
184180.136.183.0/24180.136.183.1 to 180.136.183.254180.136.183.255254
185180.136.184.0/24180.136.184.1 to 180.136.184.254180.136.184.255254
186180.136.185.0/24180.136.185.1 to 180.136.185.254180.136.185.255254
187180.136.186.0/24180.136.186.1 to 180.136.186.254180.136.186.255254
188180.136.187.0/24180.136.187.1 to 180.136.187.254180.136.187.255254
189180.136.188.0/24180.136.188.1 to 180.136.188.254180.136.188.255254
190180.136.189.0/24180.136.189.1 to 180.136.189.254180.136.189.255254
191180.136.190.0/24180.136.190.1 to 180.136.190.254180.136.190.255254
192180.136.191.0/24180.136.191.1 to 180.136.191.254180.136.191.255254
193180.136.192.0/24180.136.192.1 to 180.136.192.254180.136.192.255254
194180.136.193.0/24180.136.193.1 to 180.136.193.254180.136.193.255254
195180.136.194.0/24180.136.194.1 to 180.136.194.254180.136.194.255254
196180.136.195.0/24180.136.195.1 to 180.136.195.254180.136.195.255254
197180.136.196.0/24180.136.196.1 to 180.136.196.254180.136.196.255254
198180.136.197.0/24180.136.197.1 to 180.136.197.254180.136.197.255254
199180.136.198.0/24180.136.198.1 to 180.136.198.254180.136.198.255254
200180.136.199.0/24180.136.199.1 to 180.136.199.254180.136.199.255254
201180.136.200.0/24180.136.200.1 to 180.136.200.254180.136.200.255254
202180.136.201.0/24180.136.201.1 to 180.136.201.254180.136.201.255254
203180.136.202.0/24180.136.202.1 to 180.136.202.254180.136.202.255254
204180.136.203.0/24180.136.203.1 to 180.136.203.254180.136.203.255254
205180.136.204.0/24180.136.204.1 to 180.136.204.254180.136.204.255254
206180.136.205.0/24180.136.205.1 to 180.136.205.254180.136.205.255254
207180.136.206.0/24180.136.206.1 to 180.136.206.254180.136.206.255254
208180.136.207.0/24180.136.207.1 to 180.136.207.254180.136.207.255254
209180.136.208.0/24180.136.208.1 to 180.136.208.254180.136.208.255254
210180.136.209.0/24180.136.209.1 to 180.136.209.254180.136.209.255254
211180.136.210.0/24180.136.210.1 to 180.136.210.254180.136.210.255254
212180.136.211.0/24180.136.211.1 to 180.136.211.254180.136.211.255254
213180.136.212.0/24180.136.212.1 to 180.136.212.254180.136.212.255254
214180.136.213.0/24180.136.213.1 to 180.136.213.254180.136.213.255254
215180.136.214.0/24180.136.214.1 to 180.136.214.254180.136.214.255254
216180.136.215.0/24180.136.215.1 to 180.136.215.254180.136.215.255254
217180.136.216.0/24180.136.216.1 to 180.136.216.254180.136.216.255254
218180.136.217.0/24180.136.217.1 to 180.136.217.254180.136.217.255254
219180.136.218.0/24180.136.218.1 to 180.136.218.254180.136.218.255254
220180.136.219.0/24180.136.219.1 to 180.136.219.254180.136.219.255254
221180.136.220.0/24180.136.220.1 to 180.136.220.254180.136.220.255254
222180.136.221.0/24180.136.221.1 to 180.136.221.254180.136.221.255254
223180.136.222.0/24180.136.222.1 to 180.136.222.254180.136.222.255254
224180.136.223.0/24180.136.223.1 to 180.136.223.254180.136.223.255254
225180.136.224.0/24180.136.224.1 to 180.136.224.254180.136.224.255254
226180.136.225.0/24180.136.225.1 to 180.136.225.254180.136.225.255254
227180.136.226.0/24180.136.226.1 to 180.136.226.254180.136.226.255254
228180.136.227.0/24180.136.227.1 to 180.136.227.254180.136.227.255254
229180.136.228.0/24180.136.228.1 to 180.136.228.254180.136.228.255254
230180.136.229.0/24180.136.229.1 to 180.136.229.254180.136.229.255254
231180.136.230.0/24180.136.230.1 to 180.136.230.254180.136.230.255254
232180.136.231.0/24180.136.231.1 to 180.136.231.254180.136.231.255254
233180.136.232.0/24180.136.232.1 to 180.136.232.254180.136.232.255254
234180.136.233.0/24180.136.233.1 to 180.136.233.254180.136.233.255254
235180.136.234.0/24180.136.234.1 to 180.136.234.254180.136.234.255254
236180.136.235.0/24180.136.235.1 to 180.136.235.254180.136.235.255254
237180.136.236.0/24180.136.236.1 to 180.136.236.254180.136.236.255254
238180.136.237.0/24180.136.237.1 to 180.136.237.254180.136.237.255254
239180.136.238.0/24180.136.238.1 to 180.136.238.254180.136.238.255254
240180.136.239.0/24180.136.239.1 to 180.136.239.254180.136.239.255254
241180.136.240.0/24180.136.240.1 to 180.136.240.254180.136.240.255254
242180.136.241.0/24180.136.241.1 to 180.136.241.254180.136.241.255254
243180.136.242.0/24180.136.242.1 to 180.136.242.254180.136.242.255254
244180.136.243.0/24180.136.243.1 to 180.136.243.254180.136.243.255254
245180.136.244.0/24180.136.244.1 to 180.136.244.254180.136.244.255254
246180.136.245.0/24180.136.245.1 to 180.136.245.254180.136.245.255254
247180.136.246.0/24180.136.246.1 to 180.136.246.254180.136.246.255254
248180.136.247.0/24180.136.247.1 to 180.136.247.254180.136.247.255254
249180.136.248.0/24180.136.248.1 to 180.136.248.254180.136.248.255254
250180.136.249.0/24180.136.249.1 to 180.136.249.254180.136.249.255254
251180.136.250.0/24180.136.250.1 to 180.136.250.254180.136.250.255254
252180.136.251.0/24180.136.251.1 to 180.136.251.254180.136.251.255254
253180.136.252.0/24180.136.252.1 to 180.136.252.254180.136.252.255254
254180.136.253.0/24180.136.253.1 to 180.136.253.254180.136.253.255254
255180.136.254.0/24180.136.254.1 to 180.136.254.254180.136.254.255254
256180.136.255.0/24180.136.255.1 to 180.136.255.254180.136.255.255254

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.