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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.

Network145.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
145.0.0.0
Broadcast address
145.255.255.255
First usable
145.0.0.1
Last usable
145.255.255.254
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 91000000 · Integer 2432696320 to 2449473535
Reverse DNS zone
145.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10010001..00000000.00000000.00000000145.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10010001..00000000.00000000.00000000145.0.0.0
Broadcast10010001..11111111.11111111.11111111145.255.255.255
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)

145.0.0.0/8 makes 256 subnets of /16.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1145.0.0.0/16145.0.0.1 to 145.0.255.254145.0.255.25565,534
2145.1.0.0/16145.1.0.1 to 145.1.255.254145.1.255.25565,534
3145.2.0.0/16145.2.0.1 to 145.2.255.254145.2.255.25565,534
4145.3.0.0/16145.3.0.1 to 145.3.255.254145.3.255.25565,534
5145.4.0.0/16145.4.0.1 to 145.4.255.254145.4.255.25565,534
6145.5.0.0/16145.5.0.1 to 145.5.255.254145.5.255.25565,534
7145.6.0.0/16145.6.0.1 to 145.6.255.254145.6.255.25565,534
8145.7.0.0/16145.7.0.1 to 145.7.255.254145.7.255.25565,534
9145.8.0.0/16145.8.0.1 to 145.8.255.254145.8.255.25565,534
10145.9.0.0/16145.9.0.1 to 145.9.255.254145.9.255.25565,534
11145.10.0.0/16145.10.0.1 to 145.10.255.254145.10.255.25565,534
12145.11.0.0/16145.11.0.1 to 145.11.255.254145.11.255.25565,534
13145.12.0.0/16145.12.0.1 to 145.12.255.254145.12.255.25565,534
14145.13.0.0/16145.13.0.1 to 145.13.255.254145.13.255.25565,534
15145.14.0.0/16145.14.0.1 to 145.14.255.254145.14.255.25565,534
16145.15.0.0/16145.15.0.1 to 145.15.255.254145.15.255.25565,534
17145.16.0.0/16145.16.0.1 to 145.16.255.254145.16.255.25565,534
18145.17.0.0/16145.17.0.1 to 145.17.255.254145.17.255.25565,534
19145.18.0.0/16145.18.0.1 to 145.18.255.254145.18.255.25565,534
20145.19.0.0/16145.19.0.1 to 145.19.255.254145.19.255.25565,534
21145.20.0.0/16145.20.0.1 to 145.20.255.254145.20.255.25565,534
22145.21.0.0/16145.21.0.1 to 145.21.255.254145.21.255.25565,534
23145.22.0.0/16145.22.0.1 to 145.22.255.254145.22.255.25565,534
24145.23.0.0/16145.23.0.1 to 145.23.255.254145.23.255.25565,534
25145.24.0.0/16145.24.0.1 to 145.24.255.254145.24.255.25565,534
26145.25.0.0/16145.25.0.1 to 145.25.255.254145.25.255.25565,534
27145.26.0.0/16145.26.0.1 to 145.26.255.254145.26.255.25565,534
28145.27.0.0/16145.27.0.1 to 145.27.255.254145.27.255.25565,534
29145.28.0.0/16145.28.0.1 to 145.28.255.254145.28.255.25565,534
30145.29.0.0/16145.29.0.1 to 145.29.255.254145.29.255.25565,534
31145.30.0.0/16145.30.0.1 to 145.30.255.254145.30.255.25565,534
32145.31.0.0/16145.31.0.1 to 145.31.255.254145.31.255.25565,534
33145.32.0.0/16145.32.0.1 to 145.32.255.254145.32.255.25565,534
34145.33.0.0/16145.33.0.1 to 145.33.255.254145.33.255.25565,534
35145.34.0.0/16145.34.0.1 to 145.34.255.254145.34.255.25565,534
36145.35.0.0/16145.35.0.1 to 145.35.255.254145.35.255.25565,534
37145.36.0.0/16145.36.0.1 to 145.36.255.254145.36.255.25565,534
38145.37.0.0/16145.37.0.1 to 145.37.255.254145.37.255.25565,534
39145.38.0.0/16145.38.0.1 to 145.38.255.254145.38.255.25565,534
40145.39.0.0/16145.39.0.1 to 145.39.255.254145.39.255.25565,534
41145.40.0.0/16145.40.0.1 to 145.40.255.254145.40.255.25565,534
42145.41.0.0/16145.41.0.1 to 145.41.255.254145.41.255.25565,534
43145.42.0.0/16145.42.0.1 to 145.42.255.254145.42.255.25565,534
44145.43.0.0/16145.43.0.1 to 145.43.255.254145.43.255.25565,534
45145.44.0.0/16145.44.0.1 to 145.44.255.254145.44.255.25565,534
46145.45.0.0/16145.45.0.1 to 145.45.255.254145.45.255.25565,534
47145.46.0.0/16145.46.0.1 to 145.46.255.254145.46.255.25565,534
48145.47.0.0/16145.47.0.1 to 145.47.255.254145.47.255.25565,534
49145.48.0.0/16145.48.0.1 to 145.48.255.254145.48.255.25565,534
50145.49.0.0/16145.49.0.1 to 145.49.255.254145.49.255.25565,534
51145.50.0.0/16145.50.0.1 to 145.50.255.254145.50.255.25565,534
52145.51.0.0/16145.51.0.1 to 145.51.255.254145.51.255.25565,534
53145.52.0.0/16145.52.0.1 to 145.52.255.254145.52.255.25565,534
54145.53.0.0/16145.53.0.1 to 145.53.255.254145.53.255.25565,534
55145.54.0.0/16145.54.0.1 to 145.54.255.254145.54.255.25565,534
56145.55.0.0/16145.55.0.1 to 145.55.255.254145.55.255.25565,534
57145.56.0.0/16145.56.0.1 to 145.56.255.254145.56.255.25565,534
58145.57.0.0/16145.57.0.1 to 145.57.255.254145.57.255.25565,534
59145.58.0.0/16145.58.0.1 to 145.58.255.254145.58.255.25565,534
60145.59.0.0/16145.59.0.1 to 145.59.255.254145.59.255.25565,534
61145.60.0.0/16145.60.0.1 to 145.60.255.254145.60.255.25565,534
62145.61.0.0/16145.61.0.1 to 145.61.255.254145.61.255.25565,534
63145.62.0.0/16145.62.0.1 to 145.62.255.254145.62.255.25565,534
64145.63.0.0/16145.63.0.1 to 145.63.255.254145.63.255.25565,534
65145.64.0.0/16145.64.0.1 to 145.64.255.254145.64.255.25565,534
66145.65.0.0/16145.65.0.1 to 145.65.255.254145.65.255.25565,534
67145.66.0.0/16145.66.0.1 to 145.66.255.254145.66.255.25565,534
68145.67.0.0/16145.67.0.1 to 145.67.255.254145.67.255.25565,534
69145.68.0.0/16145.68.0.1 to 145.68.255.254145.68.255.25565,534
70145.69.0.0/16145.69.0.1 to 145.69.255.254145.69.255.25565,534
71145.70.0.0/16145.70.0.1 to 145.70.255.254145.70.255.25565,534
72145.71.0.0/16145.71.0.1 to 145.71.255.254145.71.255.25565,534
73145.72.0.0/16145.72.0.1 to 145.72.255.254145.72.255.25565,534
74145.73.0.0/16145.73.0.1 to 145.73.255.254145.73.255.25565,534
75145.74.0.0/16145.74.0.1 to 145.74.255.254145.74.255.25565,534
76145.75.0.0/16145.75.0.1 to 145.75.255.254145.75.255.25565,534
77145.76.0.0/16145.76.0.1 to 145.76.255.254145.76.255.25565,534
78145.77.0.0/16145.77.0.1 to 145.77.255.254145.77.255.25565,534
79145.78.0.0/16145.78.0.1 to 145.78.255.254145.78.255.25565,534
80145.79.0.0/16145.79.0.1 to 145.79.255.254145.79.255.25565,534
81145.80.0.0/16145.80.0.1 to 145.80.255.254145.80.255.25565,534
82145.81.0.0/16145.81.0.1 to 145.81.255.254145.81.255.25565,534
83145.82.0.0/16145.82.0.1 to 145.82.255.254145.82.255.25565,534
84145.83.0.0/16145.83.0.1 to 145.83.255.254145.83.255.25565,534
85145.84.0.0/16145.84.0.1 to 145.84.255.254145.84.255.25565,534
86145.85.0.0/16145.85.0.1 to 145.85.255.254145.85.255.25565,534
87145.86.0.0/16145.86.0.1 to 145.86.255.254145.86.255.25565,534
88145.87.0.0/16145.87.0.1 to 145.87.255.254145.87.255.25565,534
89145.88.0.0/16145.88.0.1 to 145.88.255.254145.88.255.25565,534
90145.89.0.0/16145.89.0.1 to 145.89.255.254145.89.255.25565,534
91145.90.0.0/16145.90.0.1 to 145.90.255.254145.90.255.25565,534
92145.91.0.0/16145.91.0.1 to 145.91.255.254145.91.255.25565,534
93145.92.0.0/16145.92.0.1 to 145.92.255.254145.92.255.25565,534
94145.93.0.0/16145.93.0.1 to 145.93.255.254145.93.255.25565,534
95145.94.0.0/16145.94.0.1 to 145.94.255.254145.94.255.25565,534
96145.95.0.0/16145.95.0.1 to 145.95.255.254145.95.255.25565,534
97145.96.0.0/16145.96.0.1 to 145.96.255.254145.96.255.25565,534
98145.97.0.0/16145.97.0.1 to 145.97.255.254145.97.255.25565,534
99145.98.0.0/16145.98.0.1 to 145.98.255.254145.98.255.25565,534
100145.99.0.0/16145.99.0.1 to 145.99.255.254145.99.255.25565,534
101145.100.0.0/16145.100.0.1 to 145.100.255.254145.100.255.25565,534
102145.101.0.0/16145.101.0.1 to 145.101.255.254145.101.255.25565,534
103145.102.0.0/16145.102.0.1 to 145.102.255.254145.102.255.25565,534
104145.103.0.0/16145.103.0.1 to 145.103.255.254145.103.255.25565,534
105145.104.0.0/16145.104.0.1 to 145.104.255.254145.104.255.25565,534
106145.105.0.0/16145.105.0.1 to 145.105.255.254145.105.255.25565,534
107145.106.0.0/16145.106.0.1 to 145.106.255.254145.106.255.25565,534
108145.107.0.0/16145.107.0.1 to 145.107.255.254145.107.255.25565,534
109145.108.0.0/16145.108.0.1 to 145.108.255.254145.108.255.25565,534
110145.109.0.0/16145.109.0.1 to 145.109.255.254145.109.255.25565,534
111145.110.0.0/16145.110.0.1 to 145.110.255.254145.110.255.25565,534
112145.111.0.0/16145.111.0.1 to 145.111.255.254145.111.255.25565,534
113145.112.0.0/16145.112.0.1 to 145.112.255.254145.112.255.25565,534
114145.113.0.0/16145.113.0.1 to 145.113.255.254145.113.255.25565,534
115145.114.0.0/16145.114.0.1 to 145.114.255.254145.114.255.25565,534
116145.115.0.0/16145.115.0.1 to 145.115.255.254145.115.255.25565,534
117145.116.0.0/16145.116.0.1 to 145.116.255.254145.116.255.25565,534
118145.117.0.0/16145.117.0.1 to 145.117.255.254145.117.255.25565,534
119145.118.0.0/16145.118.0.1 to 145.118.255.254145.118.255.25565,534
120145.119.0.0/16145.119.0.1 to 145.119.255.254145.119.255.25565,534
121145.120.0.0/16145.120.0.1 to 145.120.255.254145.120.255.25565,534
122145.121.0.0/16145.121.0.1 to 145.121.255.254145.121.255.25565,534
123145.122.0.0/16145.122.0.1 to 145.122.255.254145.122.255.25565,534
124145.123.0.0/16145.123.0.1 to 145.123.255.254145.123.255.25565,534
125145.124.0.0/16145.124.0.1 to 145.124.255.254145.124.255.25565,534
126145.125.0.0/16145.125.0.1 to 145.125.255.254145.125.255.25565,534
127145.126.0.0/16145.126.0.1 to 145.126.255.254145.126.255.25565,534
128145.127.0.0/16145.127.0.1 to 145.127.255.254145.127.255.25565,534
129145.128.0.0/16145.128.0.1 to 145.128.255.254145.128.255.25565,534
130145.129.0.0/16145.129.0.1 to 145.129.255.254145.129.255.25565,534
131145.130.0.0/16145.130.0.1 to 145.130.255.254145.130.255.25565,534
132145.131.0.0/16145.131.0.1 to 145.131.255.254145.131.255.25565,534
133145.132.0.0/16145.132.0.1 to 145.132.255.254145.132.255.25565,534
134145.133.0.0/16145.133.0.1 to 145.133.255.254145.133.255.25565,534
135145.134.0.0/16145.134.0.1 to 145.134.255.254145.134.255.25565,534
136145.135.0.0/16145.135.0.1 to 145.135.255.254145.135.255.25565,534
137145.136.0.0/16145.136.0.1 to 145.136.255.254145.136.255.25565,534
138145.137.0.0/16145.137.0.1 to 145.137.255.254145.137.255.25565,534
139145.138.0.0/16145.138.0.1 to 145.138.255.254145.138.255.25565,534
140145.139.0.0/16145.139.0.1 to 145.139.255.254145.139.255.25565,534
141145.140.0.0/16145.140.0.1 to 145.140.255.254145.140.255.25565,534
142145.141.0.0/16145.141.0.1 to 145.141.255.254145.141.255.25565,534
143145.142.0.0/16145.142.0.1 to 145.142.255.254145.142.255.25565,534
144145.143.0.0/16145.143.0.1 to 145.143.255.254145.143.255.25565,534
145145.144.0.0/16145.144.0.1 to 145.144.255.254145.144.255.25565,534
146145.145.0.0/16145.145.0.1 to 145.145.255.254145.145.255.25565,534
147145.146.0.0/16145.146.0.1 to 145.146.255.254145.146.255.25565,534
148145.147.0.0/16145.147.0.1 to 145.147.255.254145.147.255.25565,534
149145.148.0.0/16145.148.0.1 to 145.148.255.254145.148.255.25565,534
150145.149.0.0/16145.149.0.1 to 145.149.255.254145.149.255.25565,534
151145.150.0.0/16145.150.0.1 to 145.150.255.254145.150.255.25565,534
152145.151.0.0/16145.151.0.1 to 145.151.255.254145.151.255.25565,534
153145.152.0.0/16145.152.0.1 to 145.152.255.254145.152.255.25565,534
154145.153.0.0/16145.153.0.1 to 145.153.255.254145.153.255.25565,534
155145.154.0.0/16145.154.0.1 to 145.154.255.254145.154.255.25565,534
156145.155.0.0/16145.155.0.1 to 145.155.255.254145.155.255.25565,534
157145.156.0.0/16145.156.0.1 to 145.156.255.254145.156.255.25565,534
158145.157.0.0/16145.157.0.1 to 145.157.255.254145.157.255.25565,534
159145.158.0.0/16145.158.0.1 to 145.158.255.254145.158.255.25565,534
160145.159.0.0/16145.159.0.1 to 145.159.255.254145.159.255.25565,534
161145.160.0.0/16145.160.0.1 to 145.160.255.254145.160.255.25565,534
162145.161.0.0/16145.161.0.1 to 145.161.255.254145.161.255.25565,534
163145.162.0.0/16145.162.0.1 to 145.162.255.254145.162.255.25565,534
164145.163.0.0/16145.163.0.1 to 145.163.255.254145.163.255.25565,534
165145.164.0.0/16145.164.0.1 to 145.164.255.254145.164.255.25565,534
166145.165.0.0/16145.165.0.1 to 145.165.255.254145.165.255.25565,534
167145.166.0.0/16145.166.0.1 to 145.166.255.254145.166.255.25565,534
168145.167.0.0/16145.167.0.1 to 145.167.255.254145.167.255.25565,534
169145.168.0.0/16145.168.0.1 to 145.168.255.254145.168.255.25565,534
170145.169.0.0/16145.169.0.1 to 145.169.255.254145.169.255.25565,534
171145.170.0.0/16145.170.0.1 to 145.170.255.254145.170.255.25565,534
172145.171.0.0/16145.171.0.1 to 145.171.255.254145.171.255.25565,534
173145.172.0.0/16145.172.0.1 to 145.172.255.254145.172.255.25565,534
174145.173.0.0/16145.173.0.1 to 145.173.255.254145.173.255.25565,534
175145.174.0.0/16145.174.0.1 to 145.174.255.254145.174.255.25565,534
176145.175.0.0/16145.175.0.1 to 145.175.255.254145.175.255.25565,534
177145.176.0.0/16145.176.0.1 to 145.176.255.254145.176.255.25565,534
178145.177.0.0/16145.177.0.1 to 145.177.255.254145.177.255.25565,534
179145.178.0.0/16145.178.0.1 to 145.178.255.254145.178.255.25565,534
180145.179.0.0/16145.179.0.1 to 145.179.255.254145.179.255.25565,534
181145.180.0.0/16145.180.0.1 to 145.180.255.254145.180.255.25565,534
182145.181.0.0/16145.181.0.1 to 145.181.255.254145.181.255.25565,534
183145.182.0.0/16145.182.0.1 to 145.182.255.254145.182.255.25565,534
184145.183.0.0/16145.183.0.1 to 145.183.255.254145.183.255.25565,534
185145.184.0.0/16145.184.0.1 to 145.184.255.254145.184.255.25565,534
186145.185.0.0/16145.185.0.1 to 145.185.255.254145.185.255.25565,534
187145.186.0.0/16145.186.0.1 to 145.186.255.254145.186.255.25565,534
188145.187.0.0/16145.187.0.1 to 145.187.255.254145.187.255.25565,534
189145.188.0.0/16145.188.0.1 to 145.188.255.254145.188.255.25565,534
190145.189.0.0/16145.189.0.1 to 145.189.255.254145.189.255.25565,534
191145.190.0.0/16145.190.0.1 to 145.190.255.254145.190.255.25565,534
192145.191.0.0/16145.191.0.1 to 145.191.255.254145.191.255.25565,534
193145.192.0.0/16145.192.0.1 to 145.192.255.254145.192.255.25565,534
194145.193.0.0/16145.193.0.1 to 145.193.255.254145.193.255.25565,534
195145.194.0.0/16145.194.0.1 to 145.194.255.254145.194.255.25565,534
196145.195.0.0/16145.195.0.1 to 145.195.255.254145.195.255.25565,534
197145.196.0.0/16145.196.0.1 to 145.196.255.254145.196.255.25565,534
198145.197.0.0/16145.197.0.1 to 145.197.255.254145.197.255.25565,534
199145.198.0.0/16145.198.0.1 to 145.198.255.254145.198.255.25565,534
200145.199.0.0/16145.199.0.1 to 145.199.255.254145.199.255.25565,534
201145.200.0.0/16145.200.0.1 to 145.200.255.254145.200.255.25565,534
202145.201.0.0/16145.201.0.1 to 145.201.255.254145.201.255.25565,534
203145.202.0.0/16145.202.0.1 to 145.202.255.254145.202.255.25565,534
204145.203.0.0/16145.203.0.1 to 145.203.255.254145.203.255.25565,534
205145.204.0.0/16145.204.0.1 to 145.204.255.254145.204.255.25565,534
206145.205.0.0/16145.205.0.1 to 145.205.255.254145.205.255.25565,534
207145.206.0.0/16145.206.0.1 to 145.206.255.254145.206.255.25565,534
208145.207.0.0/16145.207.0.1 to 145.207.255.254145.207.255.25565,534
209145.208.0.0/16145.208.0.1 to 145.208.255.254145.208.255.25565,534
210145.209.0.0/16145.209.0.1 to 145.209.255.254145.209.255.25565,534
211145.210.0.0/16145.210.0.1 to 145.210.255.254145.210.255.25565,534
212145.211.0.0/16145.211.0.1 to 145.211.255.254145.211.255.25565,534
213145.212.0.0/16145.212.0.1 to 145.212.255.254145.212.255.25565,534
214145.213.0.0/16145.213.0.1 to 145.213.255.254145.213.255.25565,534
215145.214.0.0/16145.214.0.1 to 145.214.255.254145.214.255.25565,534
216145.215.0.0/16145.215.0.1 to 145.215.255.254145.215.255.25565,534
217145.216.0.0/16145.216.0.1 to 145.216.255.254145.216.255.25565,534
218145.217.0.0/16145.217.0.1 to 145.217.255.254145.217.255.25565,534
219145.218.0.0/16145.218.0.1 to 145.218.255.254145.218.255.25565,534
220145.219.0.0/16145.219.0.1 to 145.219.255.254145.219.255.25565,534
221145.220.0.0/16145.220.0.1 to 145.220.255.254145.220.255.25565,534
222145.221.0.0/16145.221.0.1 to 145.221.255.254145.221.255.25565,534
223145.222.0.0/16145.222.0.1 to 145.222.255.254145.222.255.25565,534
224145.223.0.0/16145.223.0.1 to 145.223.255.254145.223.255.25565,534
225145.224.0.0/16145.224.0.1 to 145.224.255.254145.224.255.25565,534
226145.225.0.0/16145.225.0.1 to 145.225.255.254145.225.255.25565,534
227145.226.0.0/16145.226.0.1 to 145.226.255.254145.226.255.25565,534
228145.227.0.0/16145.227.0.1 to 145.227.255.254145.227.255.25565,534
229145.228.0.0/16145.228.0.1 to 145.228.255.254145.228.255.25565,534
230145.229.0.0/16145.229.0.1 to 145.229.255.254145.229.255.25565,534
231145.230.0.0/16145.230.0.1 to 145.230.255.254145.230.255.25565,534
232145.231.0.0/16145.231.0.1 to 145.231.255.254145.231.255.25565,534
233145.232.0.0/16145.232.0.1 to 145.232.255.254145.232.255.25565,534
234145.233.0.0/16145.233.0.1 to 145.233.255.254145.233.255.25565,534
235145.234.0.0/16145.234.0.1 to 145.234.255.254145.234.255.25565,534
236145.235.0.0/16145.235.0.1 to 145.235.255.254145.235.255.25565,534
237145.236.0.0/16145.236.0.1 to 145.236.255.254145.236.255.25565,534
238145.237.0.0/16145.237.0.1 to 145.237.255.254145.237.255.25565,534
239145.238.0.0/16145.238.0.1 to 145.238.255.254145.238.255.25565,534
240145.239.0.0/16145.239.0.1 to 145.239.255.254145.239.255.25565,534
241145.240.0.0/16145.240.0.1 to 145.240.255.254145.240.255.25565,534
242145.241.0.0/16145.241.0.1 to 145.241.255.254145.241.255.25565,534
243145.242.0.0/16145.242.0.1 to 145.242.255.254145.242.255.25565,534
244145.243.0.0/16145.243.0.1 to 145.243.255.254145.243.255.25565,534
245145.244.0.0/16145.244.0.1 to 145.244.255.254145.244.255.25565,534
246145.245.0.0/16145.245.0.1 to 145.245.255.254145.245.255.25565,534
247145.246.0.0/16145.246.0.1 to 145.246.255.254145.246.255.25565,534
248145.247.0.0/16145.247.0.1 to 145.247.255.254145.247.255.25565,534
249145.248.0.0/16145.248.0.1 to 145.248.255.254145.248.255.25565,534
250145.249.0.0/16145.249.0.1 to 145.249.255.254145.249.255.25565,534
251145.250.0.0/16145.250.0.1 to 145.250.255.254145.250.255.25565,534
252145.251.0.0/16145.251.0.1 to 145.251.255.254145.251.255.25565,534
253145.252.0.0/16145.252.0.1 to 145.252.255.254145.252.255.25565,534
254145.253.0.0/16145.253.0.1 to 145.253.255.254145.253.255.25565,534
255145.254.0.0/16145.254.0.1 to 145.254.255.254145.254.255.25565,534
256145.255.0.0/16145.255.0.1 to 145.255.255.254145.255.255.25565,534

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.