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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.

Network147.0.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
147.0.0.0
Broadcast address
147.15.255.255
First usable
147.0.0.1
Last usable
147.15.255.254
Usable hosts
1,048,574 (1,048,576 less the network and broadcast addresses)
Subnet mask
255.240.0.0
Wildcard mask
0.15.255.255 (Cisco ACLs, OSPF)
Prefix length
/12
Type
Public public
Old class
B (default /16)
As numbers
Hex 93000000 · Integer 2466250752 to 2467299327
Reverse DNS zones
0.147.in-addr.arpa
1.147.in-addr.arpa
2.147.in-addr.arpa
3.147.in-addr.arpa
4.147.in-addr.arpa
5.147.in-addr.arpa
6.147.in-addr.arpa
7.147.in-addr.arpa
8.147.in-addr.arpa
9.147.in-addr.arpa
10.147.in-addr.arpa
11.147.in-addr.arpa
12.147.in-addr.arpa
13.147.in-addr.arpa
14.147.in-addr.arpa
15.147.in-addr.arpa
/12 is not on a 8-bit boundary, so it takes 16 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10010011.00000000.00000000.00000000147.0.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network10010011.00000000.00000000.00000000147.0.0.0
Broadcast10010011.00001111.11111111.11111111147.15.255.255
Split into smaller subnets/23
/13 (2)/14 (4)/15 (8)/16 (16)/17 (32)/18 (64)/19 (128)/20 (256)/21 (512)/22 (1,024)/23 (2,048)/24 (4,096)

147.0.0.0/12 makes 2,048 subnets of /23; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1147.0.0.0/23147.0.0.1 to 147.0.1.254147.0.1.255510
2147.0.2.0/23147.0.2.1 to 147.0.3.254147.0.3.255510
3147.0.4.0/23147.0.4.1 to 147.0.5.254147.0.5.255510
4147.0.6.0/23147.0.6.1 to 147.0.7.254147.0.7.255510
5147.0.8.0/23147.0.8.1 to 147.0.9.254147.0.9.255510
6147.0.10.0/23147.0.10.1 to 147.0.11.254147.0.11.255510
7147.0.12.0/23147.0.12.1 to 147.0.13.254147.0.13.255510
8147.0.14.0/23147.0.14.1 to 147.0.15.254147.0.15.255510
9147.0.16.0/23147.0.16.1 to 147.0.17.254147.0.17.255510
10147.0.18.0/23147.0.18.1 to 147.0.19.254147.0.19.255510
11147.0.20.0/23147.0.20.1 to 147.0.21.254147.0.21.255510
12147.0.22.0/23147.0.22.1 to 147.0.23.254147.0.23.255510
13147.0.24.0/23147.0.24.1 to 147.0.25.254147.0.25.255510
14147.0.26.0/23147.0.26.1 to 147.0.27.254147.0.27.255510
15147.0.28.0/23147.0.28.1 to 147.0.29.254147.0.29.255510
16147.0.30.0/23147.0.30.1 to 147.0.31.254147.0.31.255510
17147.0.32.0/23147.0.32.1 to 147.0.33.254147.0.33.255510
18147.0.34.0/23147.0.34.1 to 147.0.35.254147.0.35.255510
19147.0.36.0/23147.0.36.1 to 147.0.37.254147.0.37.255510
20147.0.38.0/23147.0.38.1 to 147.0.39.254147.0.39.255510
21147.0.40.0/23147.0.40.1 to 147.0.41.254147.0.41.255510
22147.0.42.0/23147.0.42.1 to 147.0.43.254147.0.43.255510
23147.0.44.0/23147.0.44.1 to 147.0.45.254147.0.45.255510
24147.0.46.0/23147.0.46.1 to 147.0.47.254147.0.47.255510
25147.0.48.0/23147.0.48.1 to 147.0.49.254147.0.49.255510
26147.0.50.0/23147.0.50.1 to 147.0.51.254147.0.51.255510
27147.0.52.0/23147.0.52.1 to 147.0.53.254147.0.53.255510
28147.0.54.0/23147.0.54.1 to 147.0.55.254147.0.55.255510
29147.0.56.0/23147.0.56.1 to 147.0.57.254147.0.57.255510
30147.0.58.0/23147.0.58.1 to 147.0.59.254147.0.59.255510
31147.0.60.0/23147.0.60.1 to 147.0.61.254147.0.61.255510
32147.0.62.0/23147.0.62.1 to 147.0.63.254147.0.63.255510
33147.0.64.0/23147.0.64.1 to 147.0.65.254147.0.65.255510
34147.0.66.0/23147.0.66.1 to 147.0.67.254147.0.67.255510
35147.0.68.0/23147.0.68.1 to 147.0.69.254147.0.69.255510
36147.0.70.0/23147.0.70.1 to 147.0.71.254147.0.71.255510
37147.0.72.0/23147.0.72.1 to 147.0.73.254147.0.73.255510
38147.0.74.0/23147.0.74.1 to 147.0.75.254147.0.75.255510
39147.0.76.0/23147.0.76.1 to 147.0.77.254147.0.77.255510
40147.0.78.0/23147.0.78.1 to 147.0.79.254147.0.79.255510
41147.0.80.0/23147.0.80.1 to 147.0.81.254147.0.81.255510
42147.0.82.0/23147.0.82.1 to 147.0.83.254147.0.83.255510
43147.0.84.0/23147.0.84.1 to 147.0.85.254147.0.85.255510
44147.0.86.0/23147.0.86.1 to 147.0.87.254147.0.87.255510
45147.0.88.0/23147.0.88.1 to 147.0.89.254147.0.89.255510
46147.0.90.0/23147.0.90.1 to 147.0.91.254147.0.91.255510
47147.0.92.0/23147.0.92.1 to 147.0.93.254147.0.93.255510
48147.0.94.0/23147.0.94.1 to 147.0.95.254147.0.95.255510
49147.0.96.0/23147.0.96.1 to 147.0.97.254147.0.97.255510
50147.0.98.0/23147.0.98.1 to 147.0.99.254147.0.99.255510
51147.0.100.0/23147.0.100.1 to 147.0.101.254147.0.101.255510
52147.0.102.0/23147.0.102.1 to 147.0.103.254147.0.103.255510
53147.0.104.0/23147.0.104.1 to 147.0.105.254147.0.105.255510
54147.0.106.0/23147.0.106.1 to 147.0.107.254147.0.107.255510
55147.0.108.0/23147.0.108.1 to 147.0.109.254147.0.109.255510
56147.0.110.0/23147.0.110.1 to 147.0.111.254147.0.111.255510
57147.0.112.0/23147.0.112.1 to 147.0.113.254147.0.113.255510
58147.0.114.0/23147.0.114.1 to 147.0.115.254147.0.115.255510
59147.0.116.0/23147.0.116.1 to 147.0.117.254147.0.117.255510
60147.0.118.0/23147.0.118.1 to 147.0.119.254147.0.119.255510
61147.0.120.0/23147.0.120.1 to 147.0.121.254147.0.121.255510
62147.0.122.0/23147.0.122.1 to 147.0.123.254147.0.123.255510
63147.0.124.0/23147.0.124.1 to 147.0.125.254147.0.125.255510
64147.0.126.0/23147.0.126.1 to 147.0.127.254147.0.127.255510
65147.0.128.0/23147.0.128.1 to 147.0.129.254147.0.129.255510
66147.0.130.0/23147.0.130.1 to 147.0.131.254147.0.131.255510
67147.0.132.0/23147.0.132.1 to 147.0.133.254147.0.133.255510
68147.0.134.0/23147.0.134.1 to 147.0.135.254147.0.135.255510
69147.0.136.0/23147.0.136.1 to 147.0.137.254147.0.137.255510
70147.0.138.0/23147.0.138.1 to 147.0.139.254147.0.139.255510
71147.0.140.0/23147.0.140.1 to 147.0.141.254147.0.141.255510
72147.0.142.0/23147.0.142.1 to 147.0.143.254147.0.143.255510
73147.0.144.0/23147.0.144.1 to 147.0.145.254147.0.145.255510
74147.0.146.0/23147.0.146.1 to 147.0.147.254147.0.147.255510
75147.0.148.0/23147.0.148.1 to 147.0.149.254147.0.149.255510
76147.0.150.0/23147.0.150.1 to 147.0.151.254147.0.151.255510
77147.0.152.0/23147.0.152.1 to 147.0.153.254147.0.153.255510
78147.0.154.0/23147.0.154.1 to 147.0.155.254147.0.155.255510
79147.0.156.0/23147.0.156.1 to 147.0.157.254147.0.157.255510
80147.0.158.0/23147.0.158.1 to 147.0.159.254147.0.159.255510
81147.0.160.0/23147.0.160.1 to 147.0.161.254147.0.161.255510
82147.0.162.0/23147.0.162.1 to 147.0.163.254147.0.163.255510
83147.0.164.0/23147.0.164.1 to 147.0.165.254147.0.165.255510
84147.0.166.0/23147.0.166.1 to 147.0.167.254147.0.167.255510
85147.0.168.0/23147.0.168.1 to 147.0.169.254147.0.169.255510
86147.0.170.0/23147.0.170.1 to 147.0.171.254147.0.171.255510
87147.0.172.0/23147.0.172.1 to 147.0.173.254147.0.173.255510
88147.0.174.0/23147.0.174.1 to 147.0.175.254147.0.175.255510
89147.0.176.0/23147.0.176.1 to 147.0.177.254147.0.177.255510
90147.0.178.0/23147.0.178.1 to 147.0.179.254147.0.179.255510
91147.0.180.0/23147.0.180.1 to 147.0.181.254147.0.181.255510
92147.0.182.0/23147.0.182.1 to 147.0.183.254147.0.183.255510
93147.0.184.0/23147.0.184.1 to 147.0.185.254147.0.185.255510
94147.0.186.0/23147.0.186.1 to 147.0.187.254147.0.187.255510
95147.0.188.0/23147.0.188.1 to 147.0.189.254147.0.189.255510
96147.0.190.0/23147.0.190.1 to 147.0.191.254147.0.191.255510
97147.0.192.0/23147.0.192.1 to 147.0.193.254147.0.193.255510
98147.0.194.0/23147.0.194.1 to 147.0.195.254147.0.195.255510
99147.0.196.0/23147.0.196.1 to 147.0.197.254147.0.197.255510
100147.0.198.0/23147.0.198.1 to 147.0.199.254147.0.199.255510
101147.0.200.0/23147.0.200.1 to 147.0.201.254147.0.201.255510
102147.0.202.0/23147.0.202.1 to 147.0.203.254147.0.203.255510
103147.0.204.0/23147.0.204.1 to 147.0.205.254147.0.205.255510
104147.0.206.0/23147.0.206.1 to 147.0.207.254147.0.207.255510
105147.0.208.0/23147.0.208.1 to 147.0.209.254147.0.209.255510
106147.0.210.0/23147.0.210.1 to 147.0.211.254147.0.211.255510
107147.0.212.0/23147.0.212.1 to 147.0.213.254147.0.213.255510
108147.0.214.0/23147.0.214.1 to 147.0.215.254147.0.215.255510
109147.0.216.0/23147.0.216.1 to 147.0.217.254147.0.217.255510
110147.0.218.0/23147.0.218.1 to 147.0.219.254147.0.219.255510
111147.0.220.0/23147.0.220.1 to 147.0.221.254147.0.221.255510
112147.0.222.0/23147.0.222.1 to 147.0.223.254147.0.223.255510
113147.0.224.0/23147.0.224.1 to 147.0.225.254147.0.225.255510
114147.0.226.0/23147.0.226.1 to 147.0.227.254147.0.227.255510
115147.0.228.0/23147.0.228.1 to 147.0.229.254147.0.229.255510
116147.0.230.0/23147.0.230.1 to 147.0.231.254147.0.231.255510
117147.0.232.0/23147.0.232.1 to 147.0.233.254147.0.233.255510
118147.0.234.0/23147.0.234.1 to 147.0.235.254147.0.235.255510
119147.0.236.0/23147.0.236.1 to 147.0.237.254147.0.237.255510
120147.0.238.0/23147.0.238.1 to 147.0.239.254147.0.239.255510
121147.0.240.0/23147.0.240.1 to 147.0.241.254147.0.241.255510
122147.0.242.0/23147.0.242.1 to 147.0.243.254147.0.243.255510
123147.0.244.0/23147.0.244.1 to 147.0.245.254147.0.245.255510
124147.0.246.0/23147.0.246.1 to 147.0.247.254147.0.247.255510
125147.0.248.0/23147.0.248.1 to 147.0.249.254147.0.249.255510
126147.0.250.0/23147.0.250.1 to 147.0.251.254147.0.251.255510
127147.0.252.0/23147.0.252.1 to 147.0.253.254147.0.253.255510
128147.0.254.0/23147.0.254.1 to 147.0.255.254147.0.255.255510
129147.1.0.0/23147.1.0.1 to 147.1.1.254147.1.1.255510
130147.1.2.0/23147.1.2.1 to 147.1.3.254147.1.3.255510
131147.1.4.0/23147.1.4.1 to 147.1.5.254147.1.5.255510
132147.1.6.0/23147.1.6.1 to 147.1.7.254147.1.7.255510
133147.1.8.0/23147.1.8.1 to 147.1.9.254147.1.9.255510
134147.1.10.0/23147.1.10.1 to 147.1.11.254147.1.11.255510
135147.1.12.0/23147.1.12.1 to 147.1.13.254147.1.13.255510
136147.1.14.0/23147.1.14.1 to 147.1.15.254147.1.15.255510
137147.1.16.0/23147.1.16.1 to 147.1.17.254147.1.17.255510
138147.1.18.0/23147.1.18.1 to 147.1.19.254147.1.19.255510
139147.1.20.0/23147.1.20.1 to 147.1.21.254147.1.21.255510
140147.1.22.0/23147.1.22.1 to 147.1.23.254147.1.23.255510
141147.1.24.0/23147.1.24.1 to 147.1.25.254147.1.25.255510
142147.1.26.0/23147.1.26.1 to 147.1.27.254147.1.27.255510
143147.1.28.0/23147.1.28.1 to 147.1.29.254147.1.29.255510
144147.1.30.0/23147.1.30.1 to 147.1.31.254147.1.31.255510
145147.1.32.0/23147.1.32.1 to 147.1.33.254147.1.33.255510
146147.1.34.0/23147.1.34.1 to 147.1.35.254147.1.35.255510
147147.1.36.0/23147.1.36.1 to 147.1.37.254147.1.37.255510
148147.1.38.0/23147.1.38.1 to 147.1.39.254147.1.39.255510
149147.1.40.0/23147.1.40.1 to 147.1.41.254147.1.41.255510
150147.1.42.0/23147.1.42.1 to 147.1.43.254147.1.43.255510
151147.1.44.0/23147.1.44.1 to 147.1.45.254147.1.45.255510
152147.1.46.0/23147.1.46.1 to 147.1.47.254147.1.47.255510
153147.1.48.0/23147.1.48.1 to 147.1.49.254147.1.49.255510
154147.1.50.0/23147.1.50.1 to 147.1.51.254147.1.51.255510
155147.1.52.0/23147.1.52.1 to 147.1.53.254147.1.53.255510
156147.1.54.0/23147.1.54.1 to 147.1.55.254147.1.55.255510
157147.1.56.0/23147.1.56.1 to 147.1.57.254147.1.57.255510
158147.1.58.0/23147.1.58.1 to 147.1.59.254147.1.59.255510
159147.1.60.0/23147.1.60.1 to 147.1.61.254147.1.61.255510
160147.1.62.0/23147.1.62.1 to 147.1.63.254147.1.63.255510
161147.1.64.0/23147.1.64.1 to 147.1.65.254147.1.65.255510
162147.1.66.0/23147.1.66.1 to 147.1.67.254147.1.67.255510
163147.1.68.0/23147.1.68.1 to 147.1.69.254147.1.69.255510
164147.1.70.0/23147.1.70.1 to 147.1.71.254147.1.71.255510
165147.1.72.0/23147.1.72.1 to 147.1.73.254147.1.73.255510
166147.1.74.0/23147.1.74.1 to 147.1.75.254147.1.75.255510
167147.1.76.0/23147.1.76.1 to 147.1.77.254147.1.77.255510
168147.1.78.0/23147.1.78.1 to 147.1.79.254147.1.79.255510
169147.1.80.0/23147.1.80.1 to 147.1.81.254147.1.81.255510
170147.1.82.0/23147.1.82.1 to 147.1.83.254147.1.83.255510
171147.1.84.0/23147.1.84.1 to 147.1.85.254147.1.85.255510
172147.1.86.0/23147.1.86.1 to 147.1.87.254147.1.87.255510
173147.1.88.0/23147.1.88.1 to 147.1.89.254147.1.89.255510
174147.1.90.0/23147.1.90.1 to 147.1.91.254147.1.91.255510
175147.1.92.0/23147.1.92.1 to 147.1.93.254147.1.93.255510
176147.1.94.0/23147.1.94.1 to 147.1.95.254147.1.95.255510
177147.1.96.0/23147.1.96.1 to 147.1.97.254147.1.97.255510
178147.1.98.0/23147.1.98.1 to 147.1.99.254147.1.99.255510
179147.1.100.0/23147.1.100.1 to 147.1.101.254147.1.101.255510
180147.1.102.0/23147.1.102.1 to 147.1.103.254147.1.103.255510
181147.1.104.0/23147.1.104.1 to 147.1.105.254147.1.105.255510
182147.1.106.0/23147.1.106.1 to 147.1.107.254147.1.107.255510
183147.1.108.0/23147.1.108.1 to 147.1.109.254147.1.109.255510
184147.1.110.0/23147.1.110.1 to 147.1.111.254147.1.111.255510
185147.1.112.0/23147.1.112.1 to 147.1.113.254147.1.113.255510
186147.1.114.0/23147.1.114.1 to 147.1.115.254147.1.115.255510
187147.1.116.0/23147.1.116.1 to 147.1.117.254147.1.117.255510
188147.1.118.0/23147.1.118.1 to 147.1.119.254147.1.119.255510
189147.1.120.0/23147.1.120.1 to 147.1.121.254147.1.121.255510
190147.1.122.0/23147.1.122.1 to 147.1.123.254147.1.123.255510
191147.1.124.0/23147.1.124.1 to 147.1.125.254147.1.125.255510
192147.1.126.0/23147.1.126.1 to 147.1.127.254147.1.127.255510
193147.1.128.0/23147.1.128.1 to 147.1.129.254147.1.129.255510
194147.1.130.0/23147.1.130.1 to 147.1.131.254147.1.131.255510
195147.1.132.0/23147.1.132.1 to 147.1.133.254147.1.133.255510
196147.1.134.0/23147.1.134.1 to 147.1.135.254147.1.135.255510
197147.1.136.0/23147.1.136.1 to 147.1.137.254147.1.137.255510
198147.1.138.0/23147.1.138.1 to 147.1.139.254147.1.139.255510
199147.1.140.0/23147.1.140.1 to 147.1.141.254147.1.141.255510
200147.1.142.0/23147.1.142.1 to 147.1.143.254147.1.143.255510
201147.1.144.0/23147.1.144.1 to 147.1.145.254147.1.145.255510
202147.1.146.0/23147.1.146.1 to 147.1.147.254147.1.147.255510
203147.1.148.0/23147.1.148.1 to 147.1.149.254147.1.149.255510
204147.1.150.0/23147.1.150.1 to 147.1.151.254147.1.151.255510
205147.1.152.0/23147.1.152.1 to 147.1.153.254147.1.153.255510
206147.1.154.0/23147.1.154.1 to 147.1.155.254147.1.155.255510
207147.1.156.0/23147.1.156.1 to 147.1.157.254147.1.157.255510
208147.1.158.0/23147.1.158.1 to 147.1.159.254147.1.159.255510
209147.1.160.0/23147.1.160.1 to 147.1.161.254147.1.161.255510
210147.1.162.0/23147.1.162.1 to 147.1.163.254147.1.163.255510
211147.1.164.0/23147.1.164.1 to 147.1.165.254147.1.165.255510
212147.1.166.0/23147.1.166.1 to 147.1.167.254147.1.167.255510
213147.1.168.0/23147.1.168.1 to 147.1.169.254147.1.169.255510
214147.1.170.0/23147.1.170.1 to 147.1.171.254147.1.171.255510
215147.1.172.0/23147.1.172.1 to 147.1.173.254147.1.173.255510
216147.1.174.0/23147.1.174.1 to 147.1.175.254147.1.175.255510
217147.1.176.0/23147.1.176.1 to 147.1.177.254147.1.177.255510
218147.1.178.0/23147.1.178.1 to 147.1.179.254147.1.179.255510
219147.1.180.0/23147.1.180.1 to 147.1.181.254147.1.181.255510
220147.1.182.0/23147.1.182.1 to 147.1.183.254147.1.183.255510
221147.1.184.0/23147.1.184.1 to 147.1.185.254147.1.185.255510
222147.1.186.0/23147.1.186.1 to 147.1.187.254147.1.187.255510
223147.1.188.0/23147.1.188.1 to 147.1.189.254147.1.189.255510
224147.1.190.0/23147.1.190.1 to 147.1.191.254147.1.191.255510
225147.1.192.0/23147.1.192.1 to 147.1.193.254147.1.193.255510
226147.1.194.0/23147.1.194.1 to 147.1.195.254147.1.195.255510
227147.1.196.0/23147.1.196.1 to 147.1.197.254147.1.197.255510
228147.1.198.0/23147.1.198.1 to 147.1.199.254147.1.199.255510
229147.1.200.0/23147.1.200.1 to 147.1.201.254147.1.201.255510
230147.1.202.0/23147.1.202.1 to 147.1.203.254147.1.203.255510
231147.1.204.0/23147.1.204.1 to 147.1.205.254147.1.205.255510
232147.1.206.0/23147.1.206.1 to 147.1.207.254147.1.207.255510
233147.1.208.0/23147.1.208.1 to 147.1.209.254147.1.209.255510
234147.1.210.0/23147.1.210.1 to 147.1.211.254147.1.211.255510
235147.1.212.0/23147.1.212.1 to 147.1.213.254147.1.213.255510
236147.1.214.0/23147.1.214.1 to 147.1.215.254147.1.215.255510
237147.1.216.0/23147.1.216.1 to 147.1.217.254147.1.217.255510
238147.1.218.0/23147.1.218.1 to 147.1.219.254147.1.219.255510
239147.1.220.0/23147.1.220.1 to 147.1.221.254147.1.221.255510
240147.1.222.0/23147.1.222.1 to 147.1.223.254147.1.223.255510
241147.1.224.0/23147.1.224.1 to 147.1.225.254147.1.225.255510
242147.1.226.0/23147.1.226.1 to 147.1.227.254147.1.227.255510
243147.1.228.0/23147.1.228.1 to 147.1.229.254147.1.229.255510
244147.1.230.0/23147.1.230.1 to 147.1.231.254147.1.231.255510
245147.1.232.0/23147.1.232.1 to 147.1.233.254147.1.233.255510
246147.1.234.0/23147.1.234.1 to 147.1.235.254147.1.235.255510
247147.1.236.0/23147.1.236.1 to 147.1.237.254147.1.237.255510
248147.1.238.0/23147.1.238.1 to 147.1.239.254147.1.239.255510
249147.1.240.0/23147.1.240.1 to 147.1.241.254147.1.241.255510
250147.1.242.0/23147.1.242.1 to 147.1.243.254147.1.243.255510
251147.1.244.0/23147.1.244.1 to 147.1.245.254147.1.245.255510
252147.1.246.0/23147.1.246.1 to 147.1.247.254147.1.247.255510
253147.1.248.0/23147.1.248.1 to 147.1.249.254147.1.249.255510
254147.1.250.0/23147.1.250.1 to 147.1.251.254147.1.251.255510
255147.1.252.0/23147.1.252.1 to 147.1.253.254147.1.253.255510
256147.1.254.0/23147.1.254.1 to 147.1.255.254147.1.255.255510

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.