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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.

Network131.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
131.0.0.0
Broadcast address
131.255.255.255
First usable
131.0.0.1
Last usable
131.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
B (default /16)
As numbers
Hex 83000000 · Integer 2197815296 to 2214592511
Reverse DNS zone
131.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10000011..00000000.00000000.00000000131.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10000011..00000000.00000000.00000000131.0.0.0
Broadcast10000011..11111111.11111111.11111111131.255.255.255
Split into smaller subnets/16
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

131.0.0.0/8 makes 256 subnets of /16.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1131.0.0.0/16131.0.0.1 to 131.0.255.254131.0.255.25565,534
2131.1.0.0/16131.1.0.1 to 131.1.255.254131.1.255.25565,534
3131.2.0.0/16131.2.0.1 to 131.2.255.254131.2.255.25565,534
4131.3.0.0/16131.3.0.1 to 131.3.255.254131.3.255.25565,534
5131.4.0.0/16131.4.0.1 to 131.4.255.254131.4.255.25565,534
6131.5.0.0/16131.5.0.1 to 131.5.255.254131.5.255.25565,534
7131.6.0.0/16131.6.0.1 to 131.6.255.254131.6.255.25565,534
8131.7.0.0/16131.7.0.1 to 131.7.255.254131.7.255.25565,534
9131.8.0.0/16131.8.0.1 to 131.8.255.254131.8.255.25565,534
10131.9.0.0/16131.9.0.1 to 131.9.255.254131.9.255.25565,534
11131.10.0.0/16131.10.0.1 to 131.10.255.254131.10.255.25565,534
12131.11.0.0/16131.11.0.1 to 131.11.255.254131.11.255.25565,534
13131.12.0.0/16131.12.0.1 to 131.12.255.254131.12.255.25565,534
14131.13.0.0/16131.13.0.1 to 131.13.255.254131.13.255.25565,534
15131.14.0.0/16131.14.0.1 to 131.14.255.254131.14.255.25565,534
16131.15.0.0/16131.15.0.1 to 131.15.255.254131.15.255.25565,534
17131.16.0.0/16131.16.0.1 to 131.16.255.254131.16.255.25565,534
18131.17.0.0/16131.17.0.1 to 131.17.255.254131.17.255.25565,534
19131.18.0.0/16131.18.0.1 to 131.18.255.254131.18.255.25565,534
20131.19.0.0/16131.19.0.1 to 131.19.255.254131.19.255.25565,534
21131.20.0.0/16131.20.0.1 to 131.20.255.254131.20.255.25565,534
22131.21.0.0/16131.21.0.1 to 131.21.255.254131.21.255.25565,534
23131.22.0.0/16131.22.0.1 to 131.22.255.254131.22.255.25565,534
24131.23.0.0/16131.23.0.1 to 131.23.255.254131.23.255.25565,534
25131.24.0.0/16131.24.0.1 to 131.24.255.254131.24.255.25565,534
26131.25.0.0/16131.25.0.1 to 131.25.255.254131.25.255.25565,534
27131.26.0.0/16131.26.0.1 to 131.26.255.254131.26.255.25565,534
28131.27.0.0/16131.27.0.1 to 131.27.255.254131.27.255.25565,534
29131.28.0.0/16131.28.0.1 to 131.28.255.254131.28.255.25565,534
30131.29.0.0/16131.29.0.1 to 131.29.255.254131.29.255.25565,534
31131.30.0.0/16131.30.0.1 to 131.30.255.254131.30.255.25565,534
32131.31.0.0/16131.31.0.1 to 131.31.255.254131.31.255.25565,534
33131.32.0.0/16131.32.0.1 to 131.32.255.254131.32.255.25565,534
34131.33.0.0/16131.33.0.1 to 131.33.255.254131.33.255.25565,534
35131.34.0.0/16131.34.0.1 to 131.34.255.254131.34.255.25565,534
36131.35.0.0/16131.35.0.1 to 131.35.255.254131.35.255.25565,534
37131.36.0.0/16131.36.0.1 to 131.36.255.254131.36.255.25565,534
38131.37.0.0/16131.37.0.1 to 131.37.255.254131.37.255.25565,534
39131.38.0.0/16131.38.0.1 to 131.38.255.254131.38.255.25565,534
40131.39.0.0/16131.39.0.1 to 131.39.255.254131.39.255.25565,534
41131.40.0.0/16131.40.0.1 to 131.40.255.254131.40.255.25565,534
42131.41.0.0/16131.41.0.1 to 131.41.255.254131.41.255.25565,534
43131.42.0.0/16131.42.0.1 to 131.42.255.254131.42.255.25565,534
44131.43.0.0/16131.43.0.1 to 131.43.255.254131.43.255.25565,534
45131.44.0.0/16131.44.0.1 to 131.44.255.254131.44.255.25565,534
46131.45.0.0/16131.45.0.1 to 131.45.255.254131.45.255.25565,534
47131.46.0.0/16131.46.0.1 to 131.46.255.254131.46.255.25565,534
48131.47.0.0/16131.47.0.1 to 131.47.255.254131.47.255.25565,534
49131.48.0.0/16131.48.0.1 to 131.48.255.254131.48.255.25565,534
50131.49.0.0/16131.49.0.1 to 131.49.255.254131.49.255.25565,534
51131.50.0.0/16131.50.0.1 to 131.50.255.254131.50.255.25565,534
52131.51.0.0/16131.51.0.1 to 131.51.255.254131.51.255.25565,534
53131.52.0.0/16131.52.0.1 to 131.52.255.254131.52.255.25565,534
54131.53.0.0/16131.53.0.1 to 131.53.255.254131.53.255.25565,534
55131.54.0.0/16131.54.0.1 to 131.54.255.254131.54.255.25565,534
56131.55.0.0/16131.55.0.1 to 131.55.255.254131.55.255.25565,534
57131.56.0.0/16131.56.0.1 to 131.56.255.254131.56.255.25565,534
58131.57.0.0/16131.57.0.1 to 131.57.255.254131.57.255.25565,534
59131.58.0.0/16131.58.0.1 to 131.58.255.254131.58.255.25565,534
60131.59.0.0/16131.59.0.1 to 131.59.255.254131.59.255.25565,534
61131.60.0.0/16131.60.0.1 to 131.60.255.254131.60.255.25565,534
62131.61.0.0/16131.61.0.1 to 131.61.255.254131.61.255.25565,534
63131.62.0.0/16131.62.0.1 to 131.62.255.254131.62.255.25565,534
64131.63.0.0/16131.63.0.1 to 131.63.255.254131.63.255.25565,534
65131.64.0.0/16131.64.0.1 to 131.64.255.254131.64.255.25565,534
66131.65.0.0/16131.65.0.1 to 131.65.255.254131.65.255.25565,534
67131.66.0.0/16131.66.0.1 to 131.66.255.254131.66.255.25565,534
68131.67.0.0/16131.67.0.1 to 131.67.255.254131.67.255.25565,534
69131.68.0.0/16131.68.0.1 to 131.68.255.254131.68.255.25565,534
70131.69.0.0/16131.69.0.1 to 131.69.255.254131.69.255.25565,534
71131.70.0.0/16131.70.0.1 to 131.70.255.254131.70.255.25565,534
72131.71.0.0/16131.71.0.1 to 131.71.255.254131.71.255.25565,534
73131.72.0.0/16131.72.0.1 to 131.72.255.254131.72.255.25565,534
74131.73.0.0/16131.73.0.1 to 131.73.255.254131.73.255.25565,534
75131.74.0.0/16131.74.0.1 to 131.74.255.254131.74.255.25565,534
76131.75.0.0/16131.75.0.1 to 131.75.255.254131.75.255.25565,534
77131.76.0.0/16131.76.0.1 to 131.76.255.254131.76.255.25565,534
78131.77.0.0/16131.77.0.1 to 131.77.255.254131.77.255.25565,534
79131.78.0.0/16131.78.0.1 to 131.78.255.254131.78.255.25565,534
80131.79.0.0/16131.79.0.1 to 131.79.255.254131.79.255.25565,534
81131.80.0.0/16131.80.0.1 to 131.80.255.254131.80.255.25565,534
82131.81.0.0/16131.81.0.1 to 131.81.255.254131.81.255.25565,534
83131.82.0.0/16131.82.0.1 to 131.82.255.254131.82.255.25565,534
84131.83.0.0/16131.83.0.1 to 131.83.255.254131.83.255.25565,534
85131.84.0.0/16131.84.0.1 to 131.84.255.254131.84.255.25565,534
86131.85.0.0/16131.85.0.1 to 131.85.255.254131.85.255.25565,534
87131.86.0.0/16131.86.0.1 to 131.86.255.254131.86.255.25565,534
88131.87.0.0/16131.87.0.1 to 131.87.255.254131.87.255.25565,534
89131.88.0.0/16131.88.0.1 to 131.88.255.254131.88.255.25565,534
90131.89.0.0/16131.89.0.1 to 131.89.255.254131.89.255.25565,534
91131.90.0.0/16131.90.0.1 to 131.90.255.254131.90.255.25565,534
92131.91.0.0/16131.91.0.1 to 131.91.255.254131.91.255.25565,534
93131.92.0.0/16131.92.0.1 to 131.92.255.254131.92.255.25565,534
94131.93.0.0/16131.93.0.1 to 131.93.255.254131.93.255.25565,534
95131.94.0.0/16131.94.0.1 to 131.94.255.254131.94.255.25565,534
96131.95.0.0/16131.95.0.1 to 131.95.255.254131.95.255.25565,534
97131.96.0.0/16131.96.0.1 to 131.96.255.254131.96.255.25565,534
98131.97.0.0/16131.97.0.1 to 131.97.255.254131.97.255.25565,534
99131.98.0.0/16131.98.0.1 to 131.98.255.254131.98.255.25565,534
100131.99.0.0/16131.99.0.1 to 131.99.255.254131.99.255.25565,534
101131.100.0.0/16131.100.0.1 to 131.100.255.254131.100.255.25565,534
102131.101.0.0/16131.101.0.1 to 131.101.255.254131.101.255.25565,534
103131.102.0.0/16131.102.0.1 to 131.102.255.254131.102.255.25565,534
104131.103.0.0/16131.103.0.1 to 131.103.255.254131.103.255.25565,534
105131.104.0.0/16131.104.0.1 to 131.104.255.254131.104.255.25565,534
106131.105.0.0/16131.105.0.1 to 131.105.255.254131.105.255.25565,534
107131.106.0.0/16131.106.0.1 to 131.106.255.254131.106.255.25565,534
108131.107.0.0/16131.107.0.1 to 131.107.255.254131.107.255.25565,534
109131.108.0.0/16131.108.0.1 to 131.108.255.254131.108.255.25565,534
110131.109.0.0/16131.109.0.1 to 131.109.255.254131.109.255.25565,534
111131.110.0.0/16131.110.0.1 to 131.110.255.254131.110.255.25565,534
112131.111.0.0/16131.111.0.1 to 131.111.255.254131.111.255.25565,534
113131.112.0.0/16131.112.0.1 to 131.112.255.254131.112.255.25565,534
114131.113.0.0/16131.113.0.1 to 131.113.255.254131.113.255.25565,534
115131.114.0.0/16131.114.0.1 to 131.114.255.254131.114.255.25565,534
116131.115.0.0/16131.115.0.1 to 131.115.255.254131.115.255.25565,534
117131.116.0.0/16131.116.0.1 to 131.116.255.254131.116.255.25565,534
118131.117.0.0/16131.117.0.1 to 131.117.255.254131.117.255.25565,534
119131.118.0.0/16131.118.0.1 to 131.118.255.254131.118.255.25565,534
120131.119.0.0/16131.119.0.1 to 131.119.255.254131.119.255.25565,534
121131.120.0.0/16131.120.0.1 to 131.120.255.254131.120.255.25565,534
122131.121.0.0/16131.121.0.1 to 131.121.255.254131.121.255.25565,534
123131.122.0.0/16131.122.0.1 to 131.122.255.254131.122.255.25565,534
124131.123.0.0/16131.123.0.1 to 131.123.255.254131.123.255.25565,534
125131.124.0.0/16131.124.0.1 to 131.124.255.254131.124.255.25565,534
126131.125.0.0/16131.125.0.1 to 131.125.255.254131.125.255.25565,534
127131.126.0.0/16131.126.0.1 to 131.126.255.254131.126.255.25565,534
128131.127.0.0/16131.127.0.1 to 131.127.255.254131.127.255.25565,534
129131.128.0.0/16131.128.0.1 to 131.128.255.254131.128.255.25565,534
130131.129.0.0/16131.129.0.1 to 131.129.255.254131.129.255.25565,534
131131.130.0.0/16131.130.0.1 to 131.130.255.254131.130.255.25565,534
132131.131.0.0/16131.131.0.1 to 131.131.255.254131.131.255.25565,534
133131.132.0.0/16131.132.0.1 to 131.132.255.254131.132.255.25565,534
134131.133.0.0/16131.133.0.1 to 131.133.255.254131.133.255.25565,534
135131.134.0.0/16131.134.0.1 to 131.134.255.254131.134.255.25565,534
136131.135.0.0/16131.135.0.1 to 131.135.255.254131.135.255.25565,534
137131.136.0.0/16131.136.0.1 to 131.136.255.254131.136.255.25565,534
138131.137.0.0/16131.137.0.1 to 131.137.255.254131.137.255.25565,534
139131.138.0.0/16131.138.0.1 to 131.138.255.254131.138.255.25565,534
140131.139.0.0/16131.139.0.1 to 131.139.255.254131.139.255.25565,534
141131.140.0.0/16131.140.0.1 to 131.140.255.254131.140.255.25565,534
142131.141.0.0/16131.141.0.1 to 131.141.255.254131.141.255.25565,534
143131.142.0.0/16131.142.0.1 to 131.142.255.254131.142.255.25565,534
144131.143.0.0/16131.143.0.1 to 131.143.255.254131.143.255.25565,534
145131.144.0.0/16131.144.0.1 to 131.144.255.254131.144.255.25565,534
146131.145.0.0/16131.145.0.1 to 131.145.255.254131.145.255.25565,534
147131.146.0.0/16131.146.0.1 to 131.146.255.254131.146.255.25565,534
148131.147.0.0/16131.147.0.1 to 131.147.255.254131.147.255.25565,534
149131.148.0.0/16131.148.0.1 to 131.148.255.254131.148.255.25565,534
150131.149.0.0/16131.149.0.1 to 131.149.255.254131.149.255.25565,534
151131.150.0.0/16131.150.0.1 to 131.150.255.254131.150.255.25565,534
152131.151.0.0/16131.151.0.1 to 131.151.255.254131.151.255.25565,534
153131.152.0.0/16131.152.0.1 to 131.152.255.254131.152.255.25565,534
154131.153.0.0/16131.153.0.1 to 131.153.255.254131.153.255.25565,534
155131.154.0.0/16131.154.0.1 to 131.154.255.254131.154.255.25565,534
156131.155.0.0/16131.155.0.1 to 131.155.255.254131.155.255.25565,534
157131.156.0.0/16131.156.0.1 to 131.156.255.254131.156.255.25565,534
158131.157.0.0/16131.157.0.1 to 131.157.255.254131.157.255.25565,534
159131.158.0.0/16131.158.0.1 to 131.158.255.254131.158.255.25565,534
160131.159.0.0/16131.159.0.1 to 131.159.255.254131.159.255.25565,534
161131.160.0.0/16131.160.0.1 to 131.160.255.254131.160.255.25565,534
162131.161.0.0/16131.161.0.1 to 131.161.255.254131.161.255.25565,534
163131.162.0.0/16131.162.0.1 to 131.162.255.254131.162.255.25565,534
164131.163.0.0/16131.163.0.1 to 131.163.255.254131.163.255.25565,534
165131.164.0.0/16131.164.0.1 to 131.164.255.254131.164.255.25565,534
166131.165.0.0/16131.165.0.1 to 131.165.255.254131.165.255.25565,534
167131.166.0.0/16131.166.0.1 to 131.166.255.254131.166.255.25565,534
168131.167.0.0/16131.167.0.1 to 131.167.255.254131.167.255.25565,534
169131.168.0.0/16131.168.0.1 to 131.168.255.254131.168.255.25565,534
170131.169.0.0/16131.169.0.1 to 131.169.255.254131.169.255.25565,534
171131.170.0.0/16131.170.0.1 to 131.170.255.254131.170.255.25565,534
172131.171.0.0/16131.171.0.1 to 131.171.255.254131.171.255.25565,534
173131.172.0.0/16131.172.0.1 to 131.172.255.254131.172.255.25565,534
174131.173.0.0/16131.173.0.1 to 131.173.255.254131.173.255.25565,534
175131.174.0.0/16131.174.0.1 to 131.174.255.254131.174.255.25565,534
176131.175.0.0/16131.175.0.1 to 131.175.255.254131.175.255.25565,534
177131.176.0.0/16131.176.0.1 to 131.176.255.254131.176.255.25565,534
178131.177.0.0/16131.177.0.1 to 131.177.255.254131.177.255.25565,534
179131.178.0.0/16131.178.0.1 to 131.178.255.254131.178.255.25565,534
180131.179.0.0/16131.179.0.1 to 131.179.255.254131.179.255.25565,534
181131.180.0.0/16131.180.0.1 to 131.180.255.254131.180.255.25565,534
182131.181.0.0/16131.181.0.1 to 131.181.255.254131.181.255.25565,534
183131.182.0.0/16131.182.0.1 to 131.182.255.254131.182.255.25565,534
184131.183.0.0/16131.183.0.1 to 131.183.255.254131.183.255.25565,534
185131.184.0.0/16131.184.0.1 to 131.184.255.254131.184.255.25565,534
186131.185.0.0/16131.185.0.1 to 131.185.255.254131.185.255.25565,534
187131.186.0.0/16131.186.0.1 to 131.186.255.254131.186.255.25565,534
188131.187.0.0/16131.187.0.1 to 131.187.255.254131.187.255.25565,534
189131.188.0.0/16131.188.0.1 to 131.188.255.254131.188.255.25565,534
190131.189.0.0/16131.189.0.1 to 131.189.255.254131.189.255.25565,534
191131.190.0.0/16131.190.0.1 to 131.190.255.254131.190.255.25565,534
192131.191.0.0/16131.191.0.1 to 131.191.255.254131.191.255.25565,534
193131.192.0.0/16131.192.0.1 to 131.192.255.254131.192.255.25565,534
194131.193.0.0/16131.193.0.1 to 131.193.255.254131.193.255.25565,534
195131.194.0.0/16131.194.0.1 to 131.194.255.254131.194.255.25565,534
196131.195.0.0/16131.195.0.1 to 131.195.255.254131.195.255.25565,534
197131.196.0.0/16131.196.0.1 to 131.196.255.254131.196.255.25565,534
198131.197.0.0/16131.197.0.1 to 131.197.255.254131.197.255.25565,534
199131.198.0.0/16131.198.0.1 to 131.198.255.254131.198.255.25565,534
200131.199.0.0/16131.199.0.1 to 131.199.255.254131.199.255.25565,534
201131.200.0.0/16131.200.0.1 to 131.200.255.254131.200.255.25565,534
202131.201.0.0/16131.201.0.1 to 131.201.255.254131.201.255.25565,534
203131.202.0.0/16131.202.0.1 to 131.202.255.254131.202.255.25565,534
204131.203.0.0/16131.203.0.1 to 131.203.255.254131.203.255.25565,534
205131.204.0.0/16131.204.0.1 to 131.204.255.254131.204.255.25565,534
206131.205.0.0/16131.205.0.1 to 131.205.255.254131.205.255.25565,534
207131.206.0.0/16131.206.0.1 to 131.206.255.254131.206.255.25565,534
208131.207.0.0/16131.207.0.1 to 131.207.255.254131.207.255.25565,534
209131.208.0.0/16131.208.0.1 to 131.208.255.254131.208.255.25565,534
210131.209.0.0/16131.209.0.1 to 131.209.255.254131.209.255.25565,534
211131.210.0.0/16131.210.0.1 to 131.210.255.254131.210.255.25565,534
212131.211.0.0/16131.211.0.1 to 131.211.255.254131.211.255.25565,534
213131.212.0.0/16131.212.0.1 to 131.212.255.254131.212.255.25565,534
214131.213.0.0/16131.213.0.1 to 131.213.255.254131.213.255.25565,534
215131.214.0.0/16131.214.0.1 to 131.214.255.254131.214.255.25565,534
216131.215.0.0/16131.215.0.1 to 131.215.255.254131.215.255.25565,534
217131.216.0.0/16131.216.0.1 to 131.216.255.254131.216.255.25565,534
218131.217.0.0/16131.217.0.1 to 131.217.255.254131.217.255.25565,534
219131.218.0.0/16131.218.0.1 to 131.218.255.254131.218.255.25565,534
220131.219.0.0/16131.219.0.1 to 131.219.255.254131.219.255.25565,534
221131.220.0.0/16131.220.0.1 to 131.220.255.254131.220.255.25565,534
222131.221.0.0/16131.221.0.1 to 131.221.255.254131.221.255.25565,534
223131.222.0.0/16131.222.0.1 to 131.222.255.254131.222.255.25565,534
224131.223.0.0/16131.223.0.1 to 131.223.255.254131.223.255.25565,534
225131.224.0.0/16131.224.0.1 to 131.224.255.254131.224.255.25565,534
226131.225.0.0/16131.225.0.1 to 131.225.255.254131.225.255.25565,534
227131.226.0.0/16131.226.0.1 to 131.226.255.254131.226.255.25565,534
228131.227.0.0/16131.227.0.1 to 131.227.255.254131.227.255.25565,534
229131.228.0.0/16131.228.0.1 to 131.228.255.254131.228.255.25565,534
230131.229.0.0/16131.229.0.1 to 131.229.255.254131.229.255.25565,534
231131.230.0.0/16131.230.0.1 to 131.230.255.254131.230.255.25565,534
232131.231.0.0/16131.231.0.1 to 131.231.255.254131.231.255.25565,534
233131.232.0.0/16131.232.0.1 to 131.232.255.254131.232.255.25565,534
234131.233.0.0/16131.233.0.1 to 131.233.255.254131.233.255.25565,534
235131.234.0.0/16131.234.0.1 to 131.234.255.254131.234.255.25565,534
236131.235.0.0/16131.235.0.1 to 131.235.255.254131.235.255.25565,534
237131.236.0.0/16131.236.0.1 to 131.236.255.254131.236.255.25565,534
238131.237.0.0/16131.237.0.1 to 131.237.255.254131.237.255.25565,534
239131.238.0.0/16131.238.0.1 to 131.238.255.254131.238.255.25565,534
240131.239.0.0/16131.239.0.1 to 131.239.255.254131.239.255.25565,534
241131.240.0.0/16131.240.0.1 to 131.240.255.254131.240.255.25565,534
242131.241.0.0/16131.241.0.1 to 131.241.255.254131.241.255.25565,534
243131.242.0.0/16131.242.0.1 to 131.242.255.254131.242.255.25565,534
244131.243.0.0/16131.243.0.1 to 131.243.255.254131.243.255.25565,534
245131.244.0.0/16131.244.0.1 to 131.244.255.254131.244.255.25565,534
246131.245.0.0/16131.245.0.1 to 131.245.255.254131.245.255.25565,534
247131.246.0.0/16131.246.0.1 to 131.246.255.254131.246.255.25565,534
248131.247.0.0/16131.247.0.1 to 131.247.255.254131.247.255.25565,534
249131.248.0.0/16131.248.0.1 to 131.248.255.254131.248.255.25565,534
250131.249.0.0/16131.249.0.1 to 131.249.255.254131.249.255.25565,534
251131.250.0.0/16131.250.0.1 to 131.250.255.254131.250.255.25565,534
252131.251.0.0/16131.251.0.1 to 131.251.255.254131.251.255.25565,534
253131.252.0.0/16131.252.0.1 to 131.252.255.254131.252.255.25565,534
254131.253.0.0/16131.253.0.1 to 131.253.255.254131.253.255.25565,534
255131.254.0.0/16131.254.0.1 to 131.254.255.254131.254.255.25565,534
256131.255.0.0/16131.255.0.1 to 131.255.255.254131.255.255.25565,534

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.