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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.

Network144.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
144.0.0.0
Broadcast address
145.255.255.255
First usable
144.0.0.1
Last usable
145.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
B (default /16)
As numbers
Hex 90000000 · Integer 2415919104 to 2449473535
Reverse DNS zones
144.in-addr.arpa
145.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10010000.00000000.00000000.00000000144.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network10010000.00000000.00000000.00000000144.0.0.0
Broadcast10010001.11111111.11111111.11111111145.255.255.255
Split into smaller subnets/15
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

144.0.0.0/7 makes 256 subnets of /15.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1144.0.0.0/15144.0.0.1 to 144.1.255.254144.1.255.255131,070
2144.2.0.0/15144.2.0.1 to 144.3.255.254144.3.255.255131,070
3144.4.0.0/15144.4.0.1 to 144.5.255.254144.5.255.255131,070
4144.6.0.0/15144.6.0.1 to 144.7.255.254144.7.255.255131,070
5144.8.0.0/15144.8.0.1 to 144.9.255.254144.9.255.255131,070
6144.10.0.0/15144.10.0.1 to 144.11.255.254144.11.255.255131,070
7144.12.0.0/15144.12.0.1 to 144.13.255.254144.13.255.255131,070
8144.14.0.0/15144.14.0.1 to 144.15.255.254144.15.255.255131,070
9144.16.0.0/15144.16.0.1 to 144.17.255.254144.17.255.255131,070
10144.18.0.0/15144.18.0.1 to 144.19.255.254144.19.255.255131,070
11144.20.0.0/15144.20.0.1 to 144.21.255.254144.21.255.255131,070
12144.22.0.0/15144.22.0.1 to 144.23.255.254144.23.255.255131,070
13144.24.0.0/15144.24.0.1 to 144.25.255.254144.25.255.255131,070
14144.26.0.0/15144.26.0.1 to 144.27.255.254144.27.255.255131,070
15144.28.0.0/15144.28.0.1 to 144.29.255.254144.29.255.255131,070
16144.30.0.0/15144.30.0.1 to 144.31.255.254144.31.255.255131,070
17144.32.0.0/15144.32.0.1 to 144.33.255.254144.33.255.255131,070
18144.34.0.0/15144.34.0.1 to 144.35.255.254144.35.255.255131,070
19144.36.0.0/15144.36.0.1 to 144.37.255.254144.37.255.255131,070
20144.38.0.0/15144.38.0.1 to 144.39.255.254144.39.255.255131,070
21144.40.0.0/15144.40.0.1 to 144.41.255.254144.41.255.255131,070
22144.42.0.0/15144.42.0.1 to 144.43.255.254144.43.255.255131,070
23144.44.0.0/15144.44.0.1 to 144.45.255.254144.45.255.255131,070
24144.46.0.0/15144.46.0.1 to 144.47.255.254144.47.255.255131,070
25144.48.0.0/15144.48.0.1 to 144.49.255.254144.49.255.255131,070
26144.50.0.0/15144.50.0.1 to 144.51.255.254144.51.255.255131,070
27144.52.0.0/15144.52.0.1 to 144.53.255.254144.53.255.255131,070
28144.54.0.0/15144.54.0.1 to 144.55.255.254144.55.255.255131,070
29144.56.0.0/15144.56.0.1 to 144.57.255.254144.57.255.255131,070
30144.58.0.0/15144.58.0.1 to 144.59.255.254144.59.255.255131,070
31144.60.0.0/15144.60.0.1 to 144.61.255.254144.61.255.255131,070
32144.62.0.0/15144.62.0.1 to 144.63.255.254144.63.255.255131,070
33144.64.0.0/15144.64.0.1 to 144.65.255.254144.65.255.255131,070
34144.66.0.0/15144.66.0.1 to 144.67.255.254144.67.255.255131,070
35144.68.0.0/15144.68.0.1 to 144.69.255.254144.69.255.255131,070
36144.70.0.0/15144.70.0.1 to 144.71.255.254144.71.255.255131,070
37144.72.0.0/15144.72.0.1 to 144.73.255.254144.73.255.255131,070
38144.74.0.0/15144.74.0.1 to 144.75.255.254144.75.255.255131,070
39144.76.0.0/15144.76.0.1 to 144.77.255.254144.77.255.255131,070
40144.78.0.0/15144.78.0.1 to 144.79.255.254144.79.255.255131,070
41144.80.0.0/15144.80.0.1 to 144.81.255.254144.81.255.255131,070
42144.82.0.0/15144.82.0.1 to 144.83.255.254144.83.255.255131,070
43144.84.0.0/15144.84.0.1 to 144.85.255.254144.85.255.255131,070
44144.86.0.0/15144.86.0.1 to 144.87.255.254144.87.255.255131,070
45144.88.0.0/15144.88.0.1 to 144.89.255.254144.89.255.255131,070
46144.90.0.0/15144.90.0.1 to 144.91.255.254144.91.255.255131,070
47144.92.0.0/15144.92.0.1 to 144.93.255.254144.93.255.255131,070
48144.94.0.0/15144.94.0.1 to 144.95.255.254144.95.255.255131,070
49144.96.0.0/15144.96.0.1 to 144.97.255.254144.97.255.255131,070
50144.98.0.0/15144.98.0.1 to 144.99.255.254144.99.255.255131,070
51144.100.0.0/15144.100.0.1 to 144.101.255.254144.101.255.255131,070
52144.102.0.0/15144.102.0.1 to 144.103.255.254144.103.255.255131,070
53144.104.0.0/15144.104.0.1 to 144.105.255.254144.105.255.255131,070
54144.106.0.0/15144.106.0.1 to 144.107.255.254144.107.255.255131,070
55144.108.0.0/15144.108.0.1 to 144.109.255.254144.109.255.255131,070
56144.110.0.0/15144.110.0.1 to 144.111.255.254144.111.255.255131,070
57144.112.0.0/15144.112.0.1 to 144.113.255.254144.113.255.255131,070
58144.114.0.0/15144.114.0.1 to 144.115.255.254144.115.255.255131,070
59144.116.0.0/15144.116.0.1 to 144.117.255.254144.117.255.255131,070
60144.118.0.0/15144.118.0.1 to 144.119.255.254144.119.255.255131,070
61144.120.0.0/15144.120.0.1 to 144.121.255.254144.121.255.255131,070
62144.122.0.0/15144.122.0.1 to 144.123.255.254144.123.255.255131,070
63144.124.0.0/15144.124.0.1 to 144.125.255.254144.125.255.255131,070
64144.126.0.0/15144.126.0.1 to 144.127.255.254144.127.255.255131,070
65144.128.0.0/15144.128.0.1 to 144.129.255.254144.129.255.255131,070
66144.130.0.0/15144.130.0.1 to 144.131.255.254144.131.255.255131,070
67144.132.0.0/15144.132.0.1 to 144.133.255.254144.133.255.255131,070
68144.134.0.0/15144.134.0.1 to 144.135.255.254144.135.255.255131,070
69144.136.0.0/15144.136.0.1 to 144.137.255.254144.137.255.255131,070
70144.138.0.0/15144.138.0.1 to 144.139.255.254144.139.255.255131,070
71144.140.0.0/15144.140.0.1 to 144.141.255.254144.141.255.255131,070
72144.142.0.0/15144.142.0.1 to 144.143.255.254144.143.255.255131,070
73144.144.0.0/15144.144.0.1 to 144.145.255.254144.145.255.255131,070
74144.146.0.0/15144.146.0.1 to 144.147.255.254144.147.255.255131,070
75144.148.0.0/15144.148.0.1 to 144.149.255.254144.149.255.255131,070
76144.150.0.0/15144.150.0.1 to 144.151.255.254144.151.255.255131,070
77144.152.0.0/15144.152.0.1 to 144.153.255.254144.153.255.255131,070
78144.154.0.0/15144.154.0.1 to 144.155.255.254144.155.255.255131,070
79144.156.0.0/15144.156.0.1 to 144.157.255.254144.157.255.255131,070
80144.158.0.0/15144.158.0.1 to 144.159.255.254144.159.255.255131,070
81144.160.0.0/15144.160.0.1 to 144.161.255.254144.161.255.255131,070
82144.162.0.0/15144.162.0.1 to 144.163.255.254144.163.255.255131,070
83144.164.0.0/15144.164.0.1 to 144.165.255.254144.165.255.255131,070
84144.166.0.0/15144.166.0.1 to 144.167.255.254144.167.255.255131,070
85144.168.0.0/15144.168.0.1 to 144.169.255.254144.169.255.255131,070
86144.170.0.0/15144.170.0.1 to 144.171.255.254144.171.255.255131,070
87144.172.0.0/15144.172.0.1 to 144.173.255.254144.173.255.255131,070
88144.174.0.0/15144.174.0.1 to 144.175.255.254144.175.255.255131,070
89144.176.0.0/15144.176.0.1 to 144.177.255.254144.177.255.255131,070
90144.178.0.0/15144.178.0.1 to 144.179.255.254144.179.255.255131,070
91144.180.0.0/15144.180.0.1 to 144.181.255.254144.181.255.255131,070
92144.182.0.0/15144.182.0.1 to 144.183.255.254144.183.255.255131,070
93144.184.0.0/15144.184.0.1 to 144.185.255.254144.185.255.255131,070
94144.186.0.0/15144.186.0.1 to 144.187.255.254144.187.255.255131,070
95144.188.0.0/15144.188.0.1 to 144.189.255.254144.189.255.255131,070
96144.190.0.0/15144.190.0.1 to 144.191.255.254144.191.255.255131,070
97144.192.0.0/15144.192.0.1 to 144.193.255.254144.193.255.255131,070
98144.194.0.0/15144.194.0.1 to 144.195.255.254144.195.255.255131,070
99144.196.0.0/15144.196.0.1 to 144.197.255.254144.197.255.255131,070
100144.198.0.0/15144.198.0.1 to 144.199.255.254144.199.255.255131,070
101144.200.0.0/15144.200.0.1 to 144.201.255.254144.201.255.255131,070
102144.202.0.0/15144.202.0.1 to 144.203.255.254144.203.255.255131,070
103144.204.0.0/15144.204.0.1 to 144.205.255.254144.205.255.255131,070
104144.206.0.0/15144.206.0.1 to 144.207.255.254144.207.255.255131,070
105144.208.0.0/15144.208.0.1 to 144.209.255.254144.209.255.255131,070
106144.210.0.0/15144.210.0.1 to 144.211.255.254144.211.255.255131,070
107144.212.0.0/15144.212.0.1 to 144.213.255.254144.213.255.255131,070
108144.214.0.0/15144.214.0.1 to 144.215.255.254144.215.255.255131,070
109144.216.0.0/15144.216.0.1 to 144.217.255.254144.217.255.255131,070
110144.218.0.0/15144.218.0.1 to 144.219.255.254144.219.255.255131,070
111144.220.0.0/15144.220.0.1 to 144.221.255.254144.221.255.255131,070
112144.222.0.0/15144.222.0.1 to 144.223.255.254144.223.255.255131,070
113144.224.0.0/15144.224.0.1 to 144.225.255.254144.225.255.255131,070
114144.226.0.0/15144.226.0.1 to 144.227.255.254144.227.255.255131,070
115144.228.0.0/15144.228.0.1 to 144.229.255.254144.229.255.255131,070
116144.230.0.0/15144.230.0.1 to 144.231.255.254144.231.255.255131,070
117144.232.0.0/15144.232.0.1 to 144.233.255.254144.233.255.255131,070
118144.234.0.0/15144.234.0.1 to 144.235.255.254144.235.255.255131,070
119144.236.0.0/15144.236.0.1 to 144.237.255.254144.237.255.255131,070
120144.238.0.0/15144.238.0.1 to 144.239.255.254144.239.255.255131,070
121144.240.0.0/15144.240.0.1 to 144.241.255.254144.241.255.255131,070
122144.242.0.0/15144.242.0.1 to 144.243.255.254144.243.255.255131,070
123144.244.0.0/15144.244.0.1 to 144.245.255.254144.245.255.255131,070
124144.246.0.0/15144.246.0.1 to 144.247.255.254144.247.255.255131,070
125144.248.0.0/15144.248.0.1 to 144.249.255.254144.249.255.255131,070
126144.250.0.0/15144.250.0.1 to 144.251.255.254144.251.255.255131,070
127144.252.0.0/15144.252.0.1 to 144.253.255.254144.253.255.255131,070
128144.254.0.0/15144.254.0.1 to 144.255.255.254144.255.255.255131,070
129145.0.0.0/15145.0.0.1 to 145.1.255.254145.1.255.255131,070
130145.2.0.0/15145.2.0.1 to 145.3.255.254145.3.255.255131,070
131145.4.0.0/15145.4.0.1 to 145.5.255.254145.5.255.255131,070
132145.6.0.0/15145.6.0.1 to 145.7.255.254145.7.255.255131,070
133145.8.0.0/15145.8.0.1 to 145.9.255.254145.9.255.255131,070
134145.10.0.0/15145.10.0.1 to 145.11.255.254145.11.255.255131,070
135145.12.0.0/15145.12.0.1 to 145.13.255.254145.13.255.255131,070
136145.14.0.0/15145.14.0.1 to 145.15.255.254145.15.255.255131,070
137145.16.0.0/15145.16.0.1 to 145.17.255.254145.17.255.255131,070
138145.18.0.0/15145.18.0.1 to 145.19.255.254145.19.255.255131,070
139145.20.0.0/15145.20.0.1 to 145.21.255.254145.21.255.255131,070
140145.22.0.0/15145.22.0.1 to 145.23.255.254145.23.255.255131,070
141145.24.0.0/15145.24.0.1 to 145.25.255.254145.25.255.255131,070
142145.26.0.0/15145.26.0.1 to 145.27.255.254145.27.255.255131,070
143145.28.0.0/15145.28.0.1 to 145.29.255.254145.29.255.255131,070
144145.30.0.0/15145.30.0.1 to 145.31.255.254145.31.255.255131,070
145145.32.0.0/15145.32.0.1 to 145.33.255.254145.33.255.255131,070
146145.34.0.0/15145.34.0.1 to 145.35.255.254145.35.255.255131,070
147145.36.0.0/15145.36.0.1 to 145.37.255.254145.37.255.255131,070
148145.38.0.0/15145.38.0.1 to 145.39.255.254145.39.255.255131,070
149145.40.0.0/15145.40.0.1 to 145.41.255.254145.41.255.255131,070
150145.42.0.0/15145.42.0.1 to 145.43.255.254145.43.255.255131,070
151145.44.0.0/15145.44.0.1 to 145.45.255.254145.45.255.255131,070
152145.46.0.0/15145.46.0.1 to 145.47.255.254145.47.255.255131,070
153145.48.0.0/15145.48.0.1 to 145.49.255.254145.49.255.255131,070
154145.50.0.0/15145.50.0.1 to 145.51.255.254145.51.255.255131,070
155145.52.0.0/15145.52.0.1 to 145.53.255.254145.53.255.255131,070
156145.54.0.0/15145.54.0.1 to 145.55.255.254145.55.255.255131,070
157145.56.0.0/15145.56.0.1 to 145.57.255.254145.57.255.255131,070
158145.58.0.0/15145.58.0.1 to 145.59.255.254145.59.255.255131,070
159145.60.0.0/15145.60.0.1 to 145.61.255.254145.61.255.255131,070
160145.62.0.0/15145.62.0.1 to 145.63.255.254145.63.255.255131,070
161145.64.0.0/15145.64.0.1 to 145.65.255.254145.65.255.255131,070
162145.66.0.0/15145.66.0.1 to 145.67.255.254145.67.255.255131,070
163145.68.0.0/15145.68.0.1 to 145.69.255.254145.69.255.255131,070
164145.70.0.0/15145.70.0.1 to 145.71.255.254145.71.255.255131,070
165145.72.0.0/15145.72.0.1 to 145.73.255.254145.73.255.255131,070
166145.74.0.0/15145.74.0.1 to 145.75.255.254145.75.255.255131,070
167145.76.0.0/15145.76.0.1 to 145.77.255.254145.77.255.255131,070
168145.78.0.0/15145.78.0.1 to 145.79.255.254145.79.255.255131,070
169145.80.0.0/15145.80.0.1 to 145.81.255.254145.81.255.255131,070
170145.82.0.0/15145.82.0.1 to 145.83.255.254145.83.255.255131,070
171145.84.0.0/15145.84.0.1 to 145.85.255.254145.85.255.255131,070
172145.86.0.0/15145.86.0.1 to 145.87.255.254145.87.255.255131,070
173145.88.0.0/15145.88.0.1 to 145.89.255.254145.89.255.255131,070
174145.90.0.0/15145.90.0.1 to 145.91.255.254145.91.255.255131,070
175145.92.0.0/15145.92.0.1 to 145.93.255.254145.93.255.255131,070
176145.94.0.0/15145.94.0.1 to 145.95.255.254145.95.255.255131,070
177145.96.0.0/15145.96.0.1 to 145.97.255.254145.97.255.255131,070
178145.98.0.0/15145.98.0.1 to 145.99.255.254145.99.255.255131,070
179145.100.0.0/15145.100.0.1 to 145.101.255.254145.101.255.255131,070
180145.102.0.0/15145.102.0.1 to 145.103.255.254145.103.255.255131,070
181145.104.0.0/15145.104.0.1 to 145.105.255.254145.105.255.255131,070
182145.106.0.0/15145.106.0.1 to 145.107.255.254145.107.255.255131,070
183145.108.0.0/15145.108.0.1 to 145.109.255.254145.109.255.255131,070
184145.110.0.0/15145.110.0.1 to 145.111.255.254145.111.255.255131,070
185145.112.0.0/15145.112.0.1 to 145.113.255.254145.113.255.255131,070
186145.114.0.0/15145.114.0.1 to 145.115.255.254145.115.255.255131,070
187145.116.0.0/15145.116.0.1 to 145.117.255.254145.117.255.255131,070
188145.118.0.0/15145.118.0.1 to 145.119.255.254145.119.255.255131,070
189145.120.0.0/15145.120.0.1 to 145.121.255.254145.121.255.255131,070
190145.122.0.0/15145.122.0.1 to 145.123.255.254145.123.255.255131,070
191145.124.0.0/15145.124.0.1 to 145.125.255.254145.125.255.255131,070
192145.126.0.0/15145.126.0.1 to 145.127.255.254145.127.255.255131,070
193145.128.0.0/15145.128.0.1 to 145.129.255.254145.129.255.255131,070
194145.130.0.0/15145.130.0.1 to 145.131.255.254145.131.255.255131,070
195145.132.0.0/15145.132.0.1 to 145.133.255.254145.133.255.255131,070
196145.134.0.0/15145.134.0.1 to 145.135.255.254145.135.255.255131,070
197145.136.0.0/15145.136.0.1 to 145.137.255.254145.137.255.255131,070
198145.138.0.0/15145.138.0.1 to 145.139.255.254145.139.255.255131,070
199145.140.0.0/15145.140.0.1 to 145.141.255.254145.141.255.255131,070
200145.142.0.0/15145.142.0.1 to 145.143.255.254145.143.255.255131,070
201145.144.0.0/15145.144.0.1 to 145.145.255.254145.145.255.255131,070
202145.146.0.0/15145.146.0.1 to 145.147.255.254145.147.255.255131,070
203145.148.0.0/15145.148.0.1 to 145.149.255.254145.149.255.255131,070
204145.150.0.0/15145.150.0.1 to 145.151.255.254145.151.255.255131,070
205145.152.0.0/15145.152.0.1 to 145.153.255.254145.153.255.255131,070
206145.154.0.0/15145.154.0.1 to 145.155.255.254145.155.255.255131,070
207145.156.0.0/15145.156.0.1 to 145.157.255.254145.157.255.255131,070
208145.158.0.0/15145.158.0.1 to 145.159.255.254145.159.255.255131,070
209145.160.0.0/15145.160.0.1 to 145.161.255.254145.161.255.255131,070
210145.162.0.0/15145.162.0.1 to 145.163.255.254145.163.255.255131,070
211145.164.0.0/15145.164.0.1 to 145.165.255.254145.165.255.255131,070
212145.166.0.0/15145.166.0.1 to 145.167.255.254145.167.255.255131,070
213145.168.0.0/15145.168.0.1 to 145.169.255.254145.169.255.255131,070
214145.170.0.0/15145.170.0.1 to 145.171.255.254145.171.255.255131,070
215145.172.0.0/15145.172.0.1 to 145.173.255.254145.173.255.255131,070
216145.174.0.0/15145.174.0.1 to 145.175.255.254145.175.255.255131,070
217145.176.0.0/15145.176.0.1 to 145.177.255.254145.177.255.255131,070
218145.178.0.0/15145.178.0.1 to 145.179.255.254145.179.255.255131,070
219145.180.0.0/15145.180.0.1 to 145.181.255.254145.181.255.255131,070
220145.182.0.0/15145.182.0.1 to 145.183.255.254145.183.255.255131,070
221145.184.0.0/15145.184.0.1 to 145.185.255.254145.185.255.255131,070
222145.186.0.0/15145.186.0.1 to 145.187.255.254145.187.255.255131,070
223145.188.0.0/15145.188.0.1 to 145.189.255.254145.189.255.255131,070
224145.190.0.0/15145.190.0.1 to 145.191.255.254145.191.255.255131,070
225145.192.0.0/15145.192.0.1 to 145.193.255.254145.193.255.255131,070
226145.194.0.0/15145.194.0.1 to 145.195.255.254145.195.255.255131,070
227145.196.0.0/15145.196.0.1 to 145.197.255.254145.197.255.255131,070
228145.198.0.0/15145.198.0.1 to 145.199.255.254145.199.255.255131,070
229145.200.0.0/15145.200.0.1 to 145.201.255.254145.201.255.255131,070
230145.202.0.0/15145.202.0.1 to 145.203.255.254145.203.255.255131,070
231145.204.0.0/15145.204.0.1 to 145.205.255.254145.205.255.255131,070
232145.206.0.0/15145.206.0.1 to 145.207.255.254145.207.255.255131,070
233145.208.0.0/15145.208.0.1 to 145.209.255.254145.209.255.255131,070
234145.210.0.0/15145.210.0.1 to 145.211.255.254145.211.255.255131,070
235145.212.0.0/15145.212.0.1 to 145.213.255.254145.213.255.255131,070
236145.214.0.0/15145.214.0.1 to 145.215.255.254145.215.255.255131,070
237145.216.0.0/15145.216.0.1 to 145.217.255.254145.217.255.255131,070
238145.218.0.0/15145.218.0.1 to 145.219.255.254145.219.255.255131,070
239145.220.0.0/15145.220.0.1 to 145.221.255.254145.221.255.255131,070
240145.222.0.0/15145.222.0.1 to 145.223.255.254145.223.255.255131,070
241145.224.0.0/15145.224.0.1 to 145.225.255.254145.225.255.255131,070
242145.226.0.0/15145.226.0.1 to 145.227.255.254145.227.255.255131,070
243145.228.0.0/15145.228.0.1 to 145.229.255.254145.229.255.255131,070
244145.230.0.0/15145.230.0.1 to 145.231.255.254145.231.255.255131,070
245145.232.0.0/15145.232.0.1 to 145.233.255.254145.233.255.255131,070
246145.234.0.0/15145.234.0.1 to 145.235.255.254145.235.255.255131,070
247145.236.0.0/15145.236.0.1 to 145.237.255.254145.237.255.255131,070
248145.238.0.0/15145.238.0.1 to 145.239.255.254145.239.255.255131,070
249145.240.0.0/15145.240.0.1 to 145.241.255.254145.241.255.255131,070
250145.242.0.0/15145.242.0.1 to 145.243.255.254145.243.255.255131,070
251145.244.0.0/15145.244.0.1 to 145.245.255.254145.245.255.255131,070
252145.246.0.0/15145.246.0.1 to 145.247.255.254145.247.255.255131,070
253145.248.0.0/15145.248.0.1 to 145.249.255.254145.249.255.255131,070
254145.250.0.0/15145.250.0.1 to 145.251.255.254145.251.255.255131,070
255145.252.0.0/15145.252.0.1 to 145.253.255.254145.253.255.255131,070
256145.254.0.0/15145.254.0.1 to 145.255.255.254145.255.255.255131,070

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.