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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.

Network145.48.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
145.48.0.0
Broadcast address
145.63.255.255
First usable
145.48.0.1
Last usable
145.63.255.254
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 91300000 · Integer 2435842048 to 2436890623
Reverse DNS zones
48.145.in-addr.arpa
49.145.in-addr.arpa
50.145.in-addr.arpa
51.145.in-addr.arpa
52.145.in-addr.arpa
53.145.in-addr.arpa
54.145.in-addr.arpa
55.145.in-addr.arpa
56.145.in-addr.arpa
57.145.in-addr.arpa
58.145.in-addr.arpa
59.145.in-addr.arpa
60.145.in-addr.arpa
61.145.in-addr.arpa
62.145.in-addr.arpa
63.145.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
Address10010001.00110000.00000000.00000000145.48.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network10010001.00110000.00000000.00000000145.48.0.0
Broadcast10010001.00111111.11111111.11111111145.63.255.255
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)

145.48.0.0/12 makes 2,048 subnets of /23; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1145.48.0.0/23145.48.0.1 to 145.48.1.254145.48.1.255510
2145.48.2.0/23145.48.2.1 to 145.48.3.254145.48.3.255510
3145.48.4.0/23145.48.4.1 to 145.48.5.254145.48.5.255510
4145.48.6.0/23145.48.6.1 to 145.48.7.254145.48.7.255510
5145.48.8.0/23145.48.8.1 to 145.48.9.254145.48.9.255510
6145.48.10.0/23145.48.10.1 to 145.48.11.254145.48.11.255510
7145.48.12.0/23145.48.12.1 to 145.48.13.254145.48.13.255510
8145.48.14.0/23145.48.14.1 to 145.48.15.254145.48.15.255510
9145.48.16.0/23145.48.16.1 to 145.48.17.254145.48.17.255510
10145.48.18.0/23145.48.18.1 to 145.48.19.254145.48.19.255510
11145.48.20.0/23145.48.20.1 to 145.48.21.254145.48.21.255510
12145.48.22.0/23145.48.22.1 to 145.48.23.254145.48.23.255510
13145.48.24.0/23145.48.24.1 to 145.48.25.254145.48.25.255510
14145.48.26.0/23145.48.26.1 to 145.48.27.254145.48.27.255510
15145.48.28.0/23145.48.28.1 to 145.48.29.254145.48.29.255510
16145.48.30.0/23145.48.30.1 to 145.48.31.254145.48.31.255510
17145.48.32.0/23145.48.32.1 to 145.48.33.254145.48.33.255510
18145.48.34.0/23145.48.34.1 to 145.48.35.254145.48.35.255510
19145.48.36.0/23145.48.36.1 to 145.48.37.254145.48.37.255510
20145.48.38.0/23145.48.38.1 to 145.48.39.254145.48.39.255510
21145.48.40.0/23145.48.40.1 to 145.48.41.254145.48.41.255510
22145.48.42.0/23145.48.42.1 to 145.48.43.254145.48.43.255510
23145.48.44.0/23145.48.44.1 to 145.48.45.254145.48.45.255510
24145.48.46.0/23145.48.46.1 to 145.48.47.254145.48.47.255510
25145.48.48.0/23145.48.48.1 to 145.48.49.254145.48.49.255510
26145.48.50.0/23145.48.50.1 to 145.48.51.254145.48.51.255510
27145.48.52.0/23145.48.52.1 to 145.48.53.254145.48.53.255510
28145.48.54.0/23145.48.54.1 to 145.48.55.254145.48.55.255510
29145.48.56.0/23145.48.56.1 to 145.48.57.254145.48.57.255510
30145.48.58.0/23145.48.58.1 to 145.48.59.254145.48.59.255510
31145.48.60.0/23145.48.60.1 to 145.48.61.254145.48.61.255510
32145.48.62.0/23145.48.62.1 to 145.48.63.254145.48.63.255510
33145.48.64.0/23145.48.64.1 to 145.48.65.254145.48.65.255510
34145.48.66.0/23145.48.66.1 to 145.48.67.254145.48.67.255510
35145.48.68.0/23145.48.68.1 to 145.48.69.254145.48.69.255510
36145.48.70.0/23145.48.70.1 to 145.48.71.254145.48.71.255510
37145.48.72.0/23145.48.72.1 to 145.48.73.254145.48.73.255510
38145.48.74.0/23145.48.74.1 to 145.48.75.254145.48.75.255510
39145.48.76.0/23145.48.76.1 to 145.48.77.254145.48.77.255510
40145.48.78.0/23145.48.78.1 to 145.48.79.254145.48.79.255510
41145.48.80.0/23145.48.80.1 to 145.48.81.254145.48.81.255510
42145.48.82.0/23145.48.82.1 to 145.48.83.254145.48.83.255510
43145.48.84.0/23145.48.84.1 to 145.48.85.254145.48.85.255510
44145.48.86.0/23145.48.86.1 to 145.48.87.254145.48.87.255510
45145.48.88.0/23145.48.88.1 to 145.48.89.254145.48.89.255510
46145.48.90.0/23145.48.90.1 to 145.48.91.254145.48.91.255510
47145.48.92.0/23145.48.92.1 to 145.48.93.254145.48.93.255510
48145.48.94.0/23145.48.94.1 to 145.48.95.254145.48.95.255510
49145.48.96.0/23145.48.96.1 to 145.48.97.254145.48.97.255510
50145.48.98.0/23145.48.98.1 to 145.48.99.254145.48.99.255510
51145.48.100.0/23145.48.100.1 to 145.48.101.254145.48.101.255510
52145.48.102.0/23145.48.102.1 to 145.48.103.254145.48.103.255510
53145.48.104.0/23145.48.104.1 to 145.48.105.254145.48.105.255510
54145.48.106.0/23145.48.106.1 to 145.48.107.254145.48.107.255510
55145.48.108.0/23145.48.108.1 to 145.48.109.254145.48.109.255510
56145.48.110.0/23145.48.110.1 to 145.48.111.254145.48.111.255510
57145.48.112.0/23145.48.112.1 to 145.48.113.254145.48.113.255510
58145.48.114.0/23145.48.114.1 to 145.48.115.254145.48.115.255510
59145.48.116.0/23145.48.116.1 to 145.48.117.254145.48.117.255510
60145.48.118.0/23145.48.118.1 to 145.48.119.254145.48.119.255510
61145.48.120.0/23145.48.120.1 to 145.48.121.254145.48.121.255510
62145.48.122.0/23145.48.122.1 to 145.48.123.254145.48.123.255510
63145.48.124.0/23145.48.124.1 to 145.48.125.254145.48.125.255510
64145.48.126.0/23145.48.126.1 to 145.48.127.254145.48.127.255510
65145.48.128.0/23145.48.128.1 to 145.48.129.254145.48.129.255510
66145.48.130.0/23145.48.130.1 to 145.48.131.254145.48.131.255510
67145.48.132.0/23145.48.132.1 to 145.48.133.254145.48.133.255510
68145.48.134.0/23145.48.134.1 to 145.48.135.254145.48.135.255510
69145.48.136.0/23145.48.136.1 to 145.48.137.254145.48.137.255510
70145.48.138.0/23145.48.138.1 to 145.48.139.254145.48.139.255510
71145.48.140.0/23145.48.140.1 to 145.48.141.254145.48.141.255510
72145.48.142.0/23145.48.142.1 to 145.48.143.254145.48.143.255510
73145.48.144.0/23145.48.144.1 to 145.48.145.254145.48.145.255510
74145.48.146.0/23145.48.146.1 to 145.48.147.254145.48.147.255510
75145.48.148.0/23145.48.148.1 to 145.48.149.254145.48.149.255510
76145.48.150.0/23145.48.150.1 to 145.48.151.254145.48.151.255510
77145.48.152.0/23145.48.152.1 to 145.48.153.254145.48.153.255510
78145.48.154.0/23145.48.154.1 to 145.48.155.254145.48.155.255510
79145.48.156.0/23145.48.156.1 to 145.48.157.254145.48.157.255510
80145.48.158.0/23145.48.158.1 to 145.48.159.254145.48.159.255510
81145.48.160.0/23145.48.160.1 to 145.48.161.254145.48.161.255510
82145.48.162.0/23145.48.162.1 to 145.48.163.254145.48.163.255510
83145.48.164.0/23145.48.164.1 to 145.48.165.254145.48.165.255510
84145.48.166.0/23145.48.166.1 to 145.48.167.254145.48.167.255510
85145.48.168.0/23145.48.168.1 to 145.48.169.254145.48.169.255510
86145.48.170.0/23145.48.170.1 to 145.48.171.254145.48.171.255510
87145.48.172.0/23145.48.172.1 to 145.48.173.254145.48.173.255510
88145.48.174.0/23145.48.174.1 to 145.48.175.254145.48.175.255510
89145.48.176.0/23145.48.176.1 to 145.48.177.254145.48.177.255510
90145.48.178.0/23145.48.178.1 to 145.48.179.254145.48.179.255510
91145.48.180.0/23145.48.180.1 to 145.48.181.254145.48.181.255510
92145.48.182.0/23145.48.182.1 to 145.48.183.254145.48.183.255510
93145.48.184.0/23145.48.184.1 to 145.48.185.254145.48.185.255510
94145.48.186.0/23145.48.186.1 to 145.48.187.254145.48.187.255510
95145.48.188.0/23145.48.188.1 to 145.48.189.254145.48.189.255510
96145.48.190.0/23145.48.190.1 to 145.48.191.254145.48.191.255510
97145.48.192.0/23145.48.192.1 to 145.48.193.254145.48.193.255510
98145.48.194.0/23145.48.194.1 to 145.48.195.254145.48.195.255510
99145.48.196.0/23145.48.196.1 to 145.48.197.254145.48.197.255510
100145.48.198.0/23145.48.198.1 to 145.48.199.254145.48.199.255510
101145.48.200.0/23145.48.200.1 to 145.48.201.254145.48.201.255510
102145.48.202.0/23145.48.202.1 to 145.48.203.254145.48.203.255510
103145.48.204.0/23145.48.204.1 to 145.48.205.254145.48.205.255510
104145.48.206.0/23145.48.206.1 to 145.48.207.254145.48.207.255510
105145.48.208.0/23145.48.208.1 to 145.48.209.254145.48.209.255510
106145.48.210.0/23145.48.210.1 to 145.48.211.254145.48.211.255510
107145.48.212.0/23145.48.212.1 to 145.48.213.254145.48.213.255510
108145.48.214.0/23145.48.214.1 to 145.48.215.254145.48.215.255510
109145.48.216.0/23145.48.216.1 to 145.48.217.254145.48.217.255510
110145.48.218.0/23145.48.218.1 to 145.48.219.254145.48.219.255510
111145.48.220.0/23145.48.220.1 to 145.48.221.254145.48.221.255510
112145.48.222.0/23145.48.222.1 to 145.48.223.254145.48.223.255510
113145.48.224.0/23145.48.224.1 to 145.48.225.254145.48.225.255510
114145.48.226.0/23145.48.226.1 to 145.48.227.254145.48.227.255510
115145.48.228.0/23145.48.228.1 to 145.48.229.254145.48.229.255510
116145.48.230.0/23145.48.230.1 to 145.48.231.254145.48.231.255510
117145.48.232.0/23145.48.232.1 to 145.48.233.254145.48.233.255510
118145.48.234.0/23145.48.234.1 to 145.48.235.254145.48.235.255510
119145.48.236.0/23145.48.236.1 to 145.48.237.254145.48.237.255510
120145.48.238.0/23145.48.238.1 to 145.48.239.254145.48.239.255510
121145.48.240.0/23145.48.240.1 to 145.48.241.254145.48.241.255510
122145.48.242.0/23145.48.242.1 to 145.48.243.254145.48.243.255510
123145.48.244.0/23145.48.244.1 to 145.48.245.254145.48.245.255510
124145.48.246.0/23145.48.246.1 to 145.48.247.254145.48.247.255510
125145.48.248.0/23145.48.248.1 to 145.48.249.254145.48.249.255510
126145.48.250.0/23145.48.250.1 to 145.48.251.254145.48.251.255510
127145.48.252.0/23145.48.252.1 to 145.48.253.254145.48.253.255510
128145.48.254.0/23145.48.254.1 to 145.48.255.254145.48.255.255510
129145.49.0.0/23145.49.0.1 to 145.49.1.254145.49.1.255510
130145.49.2.0/23145.49.2.1 to 145.49.3.254145.49.3.255510
131145.49.4.0/23145.49.4.1 to 145.49.5.254145.49.5.255510
132145.49.6.0/23145.49.6.1 to 145.49.7.254145.49.7.255510
133145.49.8.0/23145.49.8.1 to 145.49.9.254145.49.9.255510
134145.49.10.0/23145.49.10.1 to 145.49.11.254145.49.11.255510
135145.49.12.0/23145.49.12.1 to 145.49.13.254145.49.13.255510
136145.49.14.0/23145.49.14.1 to 145.49.15.254145.49.15.255510
137145.49.16.0/23145.49.16.1 to 145.49.17.254145.49.17.255510
138145.49.18.0/23145.49.18.1 to 145.49.19.254145.49.19.255510
139145.49.20.0/23145.49.20.1 to 145.49.21.254145.49.21.255510
140145.49.22.0/23145.49.22.1 to 145.49.23.254145.49.23.255510
141145.49.24.0/23145.49.24.1 to 145.49.25.254145.49.25.255510
142145.49.26.0/23145.49.26.1 to 145.49.27.254145.49.27.255510
143145.49.28.0/23145.49.28.1 to 145.49.29.254145.49.29.255510
144145.49.30.0/23145.49.30.1 to 145.49.31.254145.49.31.255510
145145.49.32.0/23145.49.32.1 to 145.49.33.254145.49.33.255510
146145.49.34.0/23145.49.34.1 to 145.49.35.254145.49.35.255510
147145.49.36.0/23145.49.36.1 to 145.49.37.254145.49.37.255510
148145.49.38.0/23145.49.38.1 to 145.49.39.254145.49.39.255510
149145.49.40.0/23145.49.40.1 to 145.49.41.254145.49.41.255510
150145.49.42.0/23145.49.42.1 to 145.49.43.254145.49.43.255510
151145.49.44.0/23145.49.44.1 to 145.49.45.254145.49.45.255510
152145.49.46.0/23145.49.46.1 to 145.49.47.254145.49.47.255510
153145.49.48.0/23145.49.48.1 to 145.49.49.254145.49.49.255510
154145.49.50.0/23145.49.50.1 to 145.49.51.254145.49.51.255510
155145.49.52.0/23145.49.52.1 to 145.49.53.254145.49.53.255510
156145.49.54.0/23145.49.54.1 to 145.49.55.254145.49.55.255510
157145.49.56.0/23145.49.56.1 to 145.49.57.254145.49.57.255510
158145.49.58.0/23145.49.58.1 to 145.49.59.254145.49.59.255510
159145.49.60.0/23145.49.60.1 to 145.49.61.254145.49.61.255510
160145.49.62.0/23145.49.62.1 to 145.49.63.254145.49.63.255510
161145.49.64.0/23145.49.64.1 to 145.49.65.254145.49.65.255510
162145.49.66.0/23145.49.66.1 to 145.49.67.254145.49.67.255510
163145.49.68.0/23145.49.68.1 to 145.49.69.254145.49.69.255510
164145.49.70.0/23145.49.70.1 to 145.49.71.254145.49.71.255510
165145.49.72.0/23145.49.72.1 to 145.49.73.254145.49.73.255510
166145.49.74.0/23145.49.74.1 to 145.49.75.254145.49.75.255510
167145.49.76.0/23145.49.76.1 to 145.49.77.254145.49.77.255510
168145.49.78.0/23145.49.78.1 to 145.49.79.254145.49.79.255510
169145.49.80.0/23145.49.80.1 to 145.49.81.254145.49.81.255510
170145.49.82.0/23145.49.82.1 to 145.49.83.254145.49.83.255510
171145.49.84.0/23145.49.84.1 to 145.49.85.254145.49.85.255510
172145.49.86.0/23145.49.86.1 to 145.49.87.254145.49.87.255510
173145.49.88.0/23145.49.88.1 to 145.49.89.254145.49.89.255510
174145.49.90.0/23145.49.90.1 to 145.49.91.254145.49.91.255510
175145.49.92.0/23145.49.92.1 to 145.49.93.254145.49.93.255510
176145.49.94.0/23145.49.94.1 to 145.49.95.254145.49.95.255510
177145.49.96.0/23145.49.96.1 to 145.49.97.254145.49.97.255510
178145.49.98.0/23145.49.98.1 to 145.49.99.254145.49.99.255510
179145.49.100.0/23145.49.100.1 to 145.49.101.254145.49.101.255510
180145.49.102.0/23145.49.102.1 to 145.49.103.254145.49.103.255510
181145.49.104.0/23145.49.104.1 to 145.49.105.254145.49.105.255510
182145.49.106.0/23145.49.106.1 to 145.49.107.254145.49.107.255510
183145.49.108.0/23145.49.108.1 to 145.49.109.254145.49.109.255510
184145.49.110.0/23145.49.110.1 to 145.49.111.254145.49.111.255510
185145.49.112.0/23145.49.112.1 to 145.49.113.254145.49.113.255510
186145.49.114.0/23145.49.114.1 to 145.49.115.254145.49.115.255510
187145.49.116.0/23145.49.116.1 to 145.49.117.254145.49.117.255510
188145.49.118.0/23145.49.118.1 to 145.49.119.254145.49.119.255510
189145.49.120.0/23145.49.120.1 to 145.49.121.254145.49.121.255510
190145.49.122.0/23145.49.122.1 to 145.49.123.254145.49.123.255510
191145.49.124.0/23145.49.124.1 to 145.49.125.254145.49.125.255510
192145.49.126.0/23145.49.126.1 to 145.49.127.254145.49.127.255510
193145.49.128.0/23145.49.128.1 to 145.49.129.254145.49.129.255510
194145.49.130.0/23145.49.130.1 to 145.49.131.254145.49.131.255510
195145.49.132.0/23145.49.132.1 to 145.49.133.254145.49.133.255510
196145.49.134.0/23145.49.134.1 to 145.49.135.254145.49.135.255510
197145.49.136.0/23145.49.136.1 to 145.49.137.254145.49.137.255510
198145.49.138.0/23145.49.138.1 to 145.49.139.254145.49.139.255510
199145.49.140.0/23145.49.140.1 to 145.49.141.254145.49.141.255510
200145.49.142.0/23145.49.142.1 to 145.49.143.254145.49.143.255510
201145.49.144.0/23145.49.144.1 to 145.49.145.254145.49.145.255510
202145.49.146.0/23145.49.146.1 to 145.49.147.254145.49.147.255510
203145.49.148.0/23145.49.148.1 to 145.49.149.254145.49.149.255510
204145.49.150.0/23145.49.150.1 to 145.49.151.254145.49.151.255510
205145.49.152.0/23145.49.152.1 to 145.49.153.254145.49.153.255510
206145.49.154.0/23145.49.154.1 to 145.49.155.254145.49.155.255510
207145.49.156.0/23145.49.156.1 to 145.49.157.254145.49.157.255510
208145.49.158.0/23145.49.158.1 to 145.49.159.254145.49.159.255510
209145.49.160.0/23145.49.160.1 to 145.49.161.254145.49.161.255510
210145.49.162.0/23145.49.162.1 to 145.49.163.254145.49.163.255510
211145.49.164.0/23145.49.164.1 to 145.49.165.254145.49.165.255510
212145.49.166.0/23145.49.166.1 to 145.49.167.254145.49.167.255510
213145.49.168.0/23145.49.168.1 to 145.49.169.254145.49.169.255510
214145.49.170.0/23145.49.170.1 to 145.49.171.254145.49.171.255510
215145.49.172.0/23145.49.172.1 to 145.49.173.254145.49.173.255510
216145.49.174.0/23145.49.174.1 to 145.49.175.254145.49.175.255510
217145.49.176.0/23145.49.176.1 to 145.49.177.254145.49.177.255510
218145.49.178.0/23145.49.178.1 to 145.49.179.254145.49.179.255510
219145.49.180.0/23145.49.180.1 to 145.49.181.254145.49.181.255510
220145.49.182.0/23145.49.182.1 to 145.49.183.254145.49.183.255510
221145.49.184.0/23145.49.184.1 to 145.49.185.254145.49.185.255510
222145.49.186.0/23145.49.186.1 to 145.49.187.254145.49.187.255510
223145.49.188.0/23145.49.188.1 to 145.49.189.254145.49.189.255510
224145.49.190.0/23145.49.190.1 to 145.49.191.254145.49.191.255510
225145.49.192.0/23145.49.192.1 to 145.49.193.254145.49.193.255510
226145.49.194.0/23145.49.194.1 to 145.49.195.254145.49.195.255510
227145.49.196.0/23145.49.196.1 to 145.49.197.254145.49.197.255510
228145.49.198.0/23145.49.198.1 to 145.49.199.254145.49.199.255510
229145.49.200.0/23145.49.200.1 to 145.49.201.254145.49.201.255510
230145.49.202.0/23145.49.202.1 to 145.49.203.254145.49.203.255510
231145.49.204.0/23145.49.204.1 to 145.49.205.254145.49.205.255510
232145.49.206.0/23145.49.206.1 to 145.49.207.254145.49.207.255510
233145.49.208.0/23145.49.208.1 to 145.49.209.254145.49.209.255510
234145.49.210.0/23145.49.210.1 to 145.49.211.254145.49.211.255510
235145.49.212.0/23145.49.212.1 to 145.49.213.254145.49.213.255510
236145.49.214.0/23145.49.214.1 to 145.49.215.254145.49.215.255510
237145.49.216.0/23145.49.216.1 to 145.49.217.254145.49.217.255510
238145.49.218.0/23145.49.218.1 to 145.49.219.254145.49.219.255510
239145.49.220.0/23145.49.220.1 to 145.49.221.254145.49.221.255510
240145.49.222.0/23145.49.222.1 to 145.49.223.254145.49.223.255510
241145.49.224.0/23145.49.224.1 to 145.49.225.254145.49.225.255510
242145.49.226.0/23145.49.226.1 to 145.49.227.254145.49.227.255510
243145.49.228.0/23145.49.228.1 to 145.49.229.254145.49.229.255510
244145.49.230.0/23145.49.230.1 to 145.49.231.254145.49.231.255510
245145.49.232.0/23145.49.232.1 to 145.49.233.254145.49.233.255510
246145.49.234.0/23145.49.234.1 to 145.49.235.254145.49.235.255510
247145.49.236.0/23145.49.236.1 to 145.49.237.254145.49.237.255510
248145.49.238.0/23145.49.238.1 to 145.49.239.254145.49.239.255510
249145.49.240.0/23145.49.240.1 to 145.49.241.254145.49.241.255510
250145.49.242.0/23145.49.242.1 to 145.49.243.254145.49.243.255510
251145.49.244.0/23145.49.244.1 to 145.49.245.254145.49.245.255510
252145.49.246.0/23145.49.246.1 to 145.49.247.254145.49.247.255510
253145.49.248.0/23145.49.248.1 to 145.49.249.254145.49.249.255510
254145.49.250.0/23145.49.250.1 to 145.49.251.254145.49.251.255510
255145.49.252.0/23145.49.252.1 to 145.49.253.254145.49.253.255510
256145.49.254.0/23145.49.254.1 to 145.49.255.254145.49.255.255510

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.