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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.

Network128.0.0.0/2
Usable hosts1,073,741,822
Subnet mask192.0.0.0
Addresses1,073,741,824
Network address
128.0.0.0
Broadcast address
191.255.255.255
First usable
128.0.0.1
Last usable
191.255.255.254
Usable hosts
1,073,741,822 (1,073,741,824 less the network and broadcast addresses)
Subnet mask
192.0.0.0
Wildcard mask
63.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/2
Type
Public public
Old class
B (default /16)
As numbers
Hex 80000000 · Integer 2147483648 to 3221225471
Reverse DNS zones
128.in-addr.arpa
129.in-addr.arpa
130.in-addr.arpa
131.in-addr.arpa
132.in-addr.arpa
133.in-addr.arpa
134.in-addr.arpa
135.in-addr.arpa
136.in-addr.arpa
137.in-addr.arpa
138.in-addr.arpa
139.in-addr.arpa
140.in-addr.arpa
141.in-addr.arpa
142.in-addr.arpa
143.in-addr.arpa
and 48 more
/2 is not on a 8-bit boundary, so it takes 64 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10000000.00000000.00000000.00000000128.0.0.0
Subnet mask11000000.00000000.00000000.00000000192.0.0.0
Network10000000.00000000.00000000.00000000128.0.0.0
Broadcast10111111.11111111.11111111.11111111191.255.255.255
Split into smaller subnets/14
/3 (2)/4 (4)/5 (8)/6 (16)/7 (32)/8 (64)/9 (128)/10 (256)/11 (512)/12 (1,024)/13 (2,048)/14 (4,096)

128.0.0.0/2 makes 4,096 subnets of /14; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1128.0.0.0/14128.0.0.1 to 128.3.255.254128.3.255.255262,142
2128.4.0.0/14128.4.0.1 to 128.7.255.254128.7.255.255262,142
3128.8.0.0/14128.8.0.1 to 128.11.255.254128.11.255.255262,142
4128.12.0.0/14128.12.0.1 to 128.15.255.254128.15.255.255262,142
5128.16.0.0/14128.16.0.1 to 128.19.255.254128.19.255.255262,142
6128.20.0.0/14128.20.0.1 to 128.23.255.254128.23.255.255262,142
7128.24.0.0/14128.24.0.1 to 128.27.255.254128.27.255.255262,142
8128.28.0.0/14128.28.0.1 to 128.31.255.254128.31.255.255262,142
9128.32.0.0/14128.32.0.1 to 128.35.255.254128.35.255.255262,142
10128.36.0.0/14128.36.0.1 to 128.39.255.254128.39.255.255262,142
11128.40.0.0/14128.40.0.1 to 128.43.255.254128.43.255.255262,142
12128.44.0.0/14128.44.0.1 to 128.47.255.254128.47.255.255262,142
13128.48.0.0/14128.48.0.1 to 128.51.255.254128.51.255.255262,142
14128.52.0.0/14128.52.0.1 to 128.55.255.254128.55.255.255262,142
15128.56.0.0/14128.56.0.1 to 128.59.255.254128.59.255.255262,142
16128.60.0.0/14128.60.0.1 to 128.63.255.254128.63.255.255262,142
17128.64.0.0/14128.64.0.1 to 128.67.255.254128.67.255.255262,142
18128.68.0.0/14128.68.0.1 to 128.71.255.254128.71.255.255262,142
19128.72.0.0/14128.72.0.1 to 128.75.255.254128.75.255.255262,142
20128.76.0.0/14128.76.0.1 to 128.79.255.254128.79.255.255262,142
21128.80.0.0/14128.80.0.1 to 128.83.255.254128.83.255.255262,142
22128.84.0.0/14128.84.0.1 to 128.87.255.254128.87.255.255262,142
23128.88.0.0/14128.88.0.1 to 128.91.255.254128.91.255.255262,142
24128.92.0.0/14128.92.0.1 to 128.95.255.254128.95.255.255262,142
25128.96.0.0/14128.96.0.1 to 128.99.255.254128.99.255.255262,142
26128.100.0.0/14128.100.0.1 to 128.103.255.254128.103.255.255262,142
27128.104.0.0/14128.104.0.1 to 128.107.255.254128.107.255.255262,142
28128.108.0.0/14128.108.0.1 to 128.111.255.254128.111.255.255262,142
29128.112.0.0/14128.112.0.1 to 128.115.255.254128.115.255.255262,142
30128.116.0.0/14128.116.0.1 to 128.119.255.254128.119.255.255262,142
31128.120.0.0/14128.120.0.1 to 128.123.255.254128.123.255.255262,142
32128.124.0.0/14128.124.0.1 to 128.127.255.254128.127.255.255262,142
33128.128.0.0/14128.128.0.1 to 128.131.255.254128.131.255.255262,142
34128.132.0.0/14128.132.0.1 to 128.135.255.254128.135.255.255262,142
35128.136.0.0/14128.136.0.1 to 128.139.255.254128.139.255.255262,142
36128.140.0.0/14128.140.0.1 to 128.143.255.254128.143.255.255262,142
37128.144.0.0/14128.144.0.1 to 128.147.255.254128.147.255.255262,142
38128.148.0.0/14128.148.0.1 to 128.151.255.254128.151.255.255262,142
39128.152.0.0/14128.152.0.1 to 128.155.255.254128.155.255.255262,142
40128.156.0.0/14128.156.0.1 to 128.159.255.254128.159.255.255262,142
41128.160.0.0/14128.160.0.1 to 128.163.255.254128.163.255.255262,142
42128.164.0.0/14128.164.0.1 to 128.167.255.254128.167.255.255262,142
43128.168.0.0/14128.168.0.1 to 128.171.255.254128.171.255.255262,142
44128.172.0.0/14128.172.0.1 to 128.175.255.254128.175.255.255262,142
45128.176.0.0/14128.176.0.1 to 128.179.255.254128.179.255.255262,142
46128.180.0.0/14128.180.0.1 to 128.183.255.254128.183.255.255262,142
47128.184.0.0/14128.184.0.1 to 128.187.255.254128.187.255.255262,142
48128.188.0.0/14128.188.0.1 to 128.191.255.254128.191.255.255262,142
49128.192.0.0/14128.192.0.1 to 128.195.255.254128.195.255.255262,142
50128.196.0.0/14128.196.0.1 to 128.199.255.254128.199.255.255262,142
51128.200.0.0/14128.200.0.1 to 128.203.255.254128.203.255.255262,142
52128.204.0.0/14128.204.0.1 to 128.207.255.254128.207.255.255262,142
53128.208.0.0/14128.208.0.1 to 128.211.255.254128.211.255.255262,142
54128.212.0.0/14128.212.0.1 to 128.215.255.254128.215.255.255262,142
55128.216.0.0/14128.216.0.1 to 128.219.255.254128.219.255.255262,142
56128.220.0.0/14128.220.0.1 to 128.223.255.254128.223.255.255262,142
57128.224.0.0/14128.224.0.1 to 128.227.255.254128.227.255.255262,142
58128.228.0.0/14128.228.0.1 to 128.231.255.254128.231.255.255262,142
59128.232.0.0/14128.232.0.1 to 128.235.255.254128.235.255.255262,142
60128.236.0.0/14128.236.0.1 to 128.239.255.254128.239.255.255262,142
61128.240.0.0/14128.240.0.1 to 128.243.255.254128.243.255.255262,142
62128.244.0.0/14128.244.0.1 to 128.247.255.254128.247.255.255262,142
63128.248.0.0/14128.248.0.1 to 128.251.255.254128.251.255.255262,142
64128.252.0.0/14128.252.0.1 to 128.255.255.254128.255.255.255262,142
65129.0.0.0/14129.0.0.1 to 129.3.255.254129.3.255.255262,142
66129.4.0.0/14129.4.0.1 to 129.7.255.254129.7.255.255262,142
67129.8.0.0/14129.8.0.1 to 129.11.255.254129.11.255.255262,142
68129.12.0.0/14129.12.0.1 to 129.15.255.254129.15.255.255262,142
69129.16.0.0/14129.16.0.1 to 129.19.255.254129.19.255.255262,142
70129.20.0.0/14129.20.0.1 to 129.23.255.254129.23.255.255262,142
71129.24.0.0/14129.24.0.1 to 129.27.255.254129.27.255.255262,142
72129.28.0.0/14129.28.0.1 to 129.31.255.254129.31.255.255262,142
73129.32.0.0/14129.32.0.1 to 129.35.255.254129.35.255.255262,142
74129.36.0.0/14129.36.0.1 to 129.39.255.254129.39.255.255262,142
75129.40.0.0/14129.40.0.1 to 129.43.255.254129.43.255.255262,142
76129.44.0.0/14129.44.0.1 to 129.47.255.254129.47.255.255262,142
77129.48.0.0/14129.48.0.1 to 129.51.255.254129.51.255.255262,142
78129.52.0.0/14129.52.0.1 to 129.55.255.254129.55.255.255262,142
79129.56.0.0/14129.56.0.1 to 129.59.255.254129.59.255.255262,142
80129.60.0.0/14129.60.0.1 to 129.63.255.254129.63.255.255262,142
81129.64.0.0/14129.64.0.1 to 129.67.255.254129.67.255.255262,142
82129.68.0.0/14129.68.0.1 to 129.71.255.254129.71.255.255262,142
83129.72.0.0/14129.72.0.1 to 129.75.255.254129.75.255.255262,142
84129.76.0.0/14129.76.0.1 to 129.79.255.254129.79.255.255262,142
85129.80.0.0/14129.80.0.1 to 129.83.255.254129.83.255.255262,142
86129.84.0.0/14129.84.0.1 to 129.87.255.254129.87.255.255262,142
87129.88.0.0/14129.88.0.1 to 129.91.255.254129.91.255.255262,142
88129.92.0.0/14129.92.0.1 to 129.95.255.254129.95.255.255262,142
89129.96.0.0/14129.96.0.1 to 129.99.255.254129.99.255.255262,142
90129.100.0.0/14129.100.0.1 to 129.103.255.254129.103.255.255262,142
91129.104.0.0/14129.104.0.1 to 129.107.255.254129.107.255.255262,142
92129.108.0.0/14129.108.0.1 to 129.111.255.254129.111.255.255262,142
93129.112.0.0/14129.112.0.1 to 129.115.255.254129.115.255.255262,142
94129.116.0.0/14129.116.0.1 to 129.119.255.254129.119.255.255262,142
95129.120.0.0/14129.120.0.1 to 129.123.255.254129.123.255.255262,142
96129.124.0.0/14129.124.0.1 to 129.127.255.254129.127.255.255262,142
97129.128.0.0/14129.128.0.1 to 129.131.255.254129.131.255.255262,142
98129.132.0.0/14129.132.0.1 to 129.135.255.254129.135.255.255262,142
99129.136.0.0/14129.136.0.1 to 129.139.255.254129.139.255.255262,142
100129.140.0.0/14129.140.0.1 to 129.143.255.254129.143.255.255262,142
101129.144.0.0/14129.144.0.1 to 129.147.255.254129.147.255.255262,142
102129.148.0.0/14129.148.0.1 to 129.151.255.254129.151.255.255262,142
103129.152.0.0/14129.152.0.1 to 129.155.255.254129.155.255.255262,142
104129.156.0.0/14129.156.0.1 to 129.159.255.254129.159.255.255262,142
105129.160.0.0/14129.160.0.1 to 129.163.255.254129.163.255.255262,142
106129.164.0.0/14129.164.0.1 to 129.167.255.254129.167.255.255262,142
107129.168.0.0/14129.168.0.1 to 129.171.255.254129.171.255.255262,142
108129.172.0.0/14129.172.0.1 to 129.175.255.254129.175.255.255262,142
109129.176.0.0/14129.176.0.1 to 129.179.255.254129.179.255.255262,142
110129.180.0.0/14129.180.0.1 to 129.183.255.254129.183.255.255262,142
111129.184.0.0/14129.184.0.1 to 129.187.255.254129.187.255.255262,142
112129.188.0.0/14129.188.0.1 to 129.191.255.254129.191.255.255262,142
113129.192.0.0/14129.192.0.1 to 129.195.255.254129.195.255.255262,142
114129.196.0.0/14129.196.0.1 to 129.199.255.254129.199.255.255262,142
115129.200.0.0/14129.200.0.1 to 129.203.255.254129.203.255.255262,142
116129.204.0.0/14129.204.0.1 to 129.207.255.254129.207.255.255262,142
117129.208.0.0/14129.208.0.1 to 129.211.255.254129.211.255.255262,142
118129.212.0.0/14129.212.0.1 to 129.215.255.254129.215.255.255262,142
119129.216.0.0/14129.216.0.1 to 129.219.255.254129.219.255.255262,142
120129.220.0.0/14129.220.0.1 to 129.223.255.254129.223.255.255262,142
121129.224.0.0/14129.224.0.1 to 129.227.255.254129.227.255.255262,142
122129.228.0.0/14129.228.0.1 to 129.231.255.254129.231.255.255262,142
123129.232.0.0/14129.232.0.1 to 129.235.255.254129.235.255.255262,142
124129.236.0.0/14129.236.0.1 to 129.239.255.254129.239.255.255262,142
125129.240.0.0/14129.240.0.1 to 129.243.255.254129.243.255.255262,142
126129.244.0.0/14129.244.0.1 to 129.247.255.254129.247.255.255262,142
127129.248.0.0/14129.248.0.1 to 129.251.255.254129.251.255.255262,142
128129.252.0.0/14129.252.0.1 to 129.255.255.254129.255.255.255262,142
129130.0.0.0/14130.0.0.1 to 130.3.255.254130.3.255.255262,142
130130.4.0.0/14130.4.0.1 to 130.7.255.254130.7.255.255262,142
131130.8.0.0/14130.8.0.1 to 130.11.255.254130.11.255.255262,142
132130.12.0.0/14130.12.0.1 to 130.15.255.254130.15.255.255262,142
133130.16.0.0/14130.16.0.1 to 130.19.255.254130.19.255.255262,142
134130.20.0.0/14130.20.0.1 to 130.23.255.254130.23.255.255262,142
135130.24.0.0/14130.24.0.1 to 130.27.255.254130.27.255.255262,142
136130.28.0.0/14130.28.0.1 to 130.31.255.254130.31.255.255262,142
137130.32.0.0/14130.32.0.1 to 130.35.255.254130.35.255.255262,142
138130.36.0.0/14130.36.0.1 to 130.39.255.254130.39.255.255262,142
139130.40.0.0/14130.40.0.1 to 130.43.255.254130.43.255.255262,142
140130.44.0.0/14130.44.0.1 to 130.47.255.254130.47.255.255262,142
141130.48.0.0/14130.48.0.1 to 130.51.255.254130.51.255.255262,142
142130.52.0.0/14130.52.0.1 to 130.55.255.254130.55.255.255262,142
143130.56.0.0/14130.56.0.1 to 130.59.255.254130.59.255.255262,142
144130.60.0.0/14130.60.0.1 to 130.63.255.254130.63.255.255262,142
145130.64.0.0/14130.64.0.1 to 130.67.255.254130.67.255.255262,142
146130.68.0.0/14130.68.0.1 to 130.71.255.254130.71.255.255262,142
147130.72.0.0/14130.72.0.1 to 130.75.255.254130.75.255.255262,142
148130.76.0.0/14130.76.0.1 to 130.79.255.254130.79.255.255262,142
149130.80.0.0/14130.80.0.1 to 130.83.255.254130.83.255.255262,142
150130.84.0.0/14130.84.0.1 to 130.87.255.254130.87.255.255262,142
151130.88.0.0/14130.88.0.1 to 130.91.255.254130.91.255.255262,142
152130.92.0.0/14130.92.0.1 to 130.95.255.254130.95.255.255262,142
153130.96.0.0/14130.96.0.1 to 130.99.255.254130.99.255.255262,142
154130.100.0.0/14130.100.0.1 to 130.103.255.254130.103.255.255262,142
155130.104.0.0/14130.104.0.1 to 130.107.255.254130.107.255.255262,142
156130.108.0.0/14130.108.0.1 to 130.111.255.254130.111.255.255262,142
157130.112.0.0/14130.112.0.1 to 130.115.255.254130.115.255.255262,142
158130.116.0.0/14130.116.0.1 to 130.119.255.254130.119.255.255262,142
159130.120.0.0/14130.120.0.1 to 130.123.255.254130.123.255.255262,142
160130.124.0.0/14130.124.0.1 to 130.127.255.254130.127.255.255262,142
161130.128.0.0/14130.128.0.1 to 130.131.255.254130.131.255.255262,142
162130.132.0.0/14130.132.0.1 to 130.135.255.254130.135.255.255262,142
163130.136.0.0/14130.136.0.1 to 130.139.255.254130.139.255.255262,142
164130.140.0.0/14130.140.0.1 to 130.143.255.254130.143.255.255262,142
165130.144.0.0/14130.144.0.1 to 130.147.255.254130.147.255.255262,142
166130.148.0.0/14130.148.0.1 to 130.151.255.254130.151.255.255262,142
167130.152.0.0/14130.152.0.1 to 130.155.255.254130.155.255.255262,142
168130.156.0.0/14130.156.0.1 to 130.159.255.254130.159.255.255262,142
169130.160.0.0/14130.160.0.1 to 130.163.255.254130.163.255.255262,142
170130.164.0.0/14130.164.0.1 to 130.167.255.254130.167.255.255262,142
171130.168.0.0/14130.168.0.1 to 130.171.255.254130.171.255.255262,142
172130.172.0.0/14130.172.0.1 to 130.175.255.254130.175.255.255262,142
173130.176.0.0/14130.176.0.1 to 130.179.255.254130.179.255.255262,142
174130.180.0.0/14130.180.0.1 to 130.183.255.254130.183.255.255262,142
175130.184.0.0/14130.184.0.1 to 130.187.255.254130.187.255.255262,142
176130.188.0.0/14130.188.0.1 to 130.191.255.254130.191.255.255262,142
177130.192.0.0/14130.192.0.1 to 130.195.255.254130.195.255.255262,142
178130.196.0.0/14130.196.0.1 to 130.199.255.254130.199.255.255262,142
179130.200.0.0/14130.200.0.1 to 130.203.255.254130.203.255.255262,142
180130.204.0.0/14130.204.0.1 to 130.207.255.254130.207.255.255262,142
181130.208.0.0/14130.208.0.1 to 130.211.255.254130.211.255.255262,142
182130.212.0.0/14130.212.0.1 to 130.215.255.254130.215.255.255262,142
183130.216.0.0/14130.216.0.1 to 130.219.255.254130.219.255.255262,142
184130.220.0.0/14130.220.0.1 to 130.223.255.254130.223.255.255262,142
185130.224.0.0/14130.224.0.1 to 130.227.255.254130.227.255.255262,142
186130.228.0.0/14130.228.0.1 to 130.231.255.254130.231.255.255262,142
187130.232.0.0/14130.232.0.1 to 130.235.255.254130.235.255.255262,142
188130.236.0.0/14130.236.0.1 to 130.239.255.254130.239.255.255262,142
189130.240.0.0/14130.240.0.1 to 130.243.255.254130.243.255.255262,142
190130.244.0.0/14130.244.0.1 to 130.247.255.254130.247.255.255262,142
191130.248.0.0/14130.248.0.1 to 130.251.255.254130.251.255.255262,142
192130.252.0.0/14130.252.0.1 to 130.255.255.254130.255.255.255262,142
193131.0.0.0/14131.0.0.1 to 131.3.255.254131.3.255.255262,142
194131.4.0.0/14131.4.0.1 to 131.7.255.254131.7.255.255262,142
195131.8.0.0/14131.8.0.1 to 131.11.255.254131.11.255.255262,142
196131.12.0.0/14131.12.0.1 to 131.15.255.254131.15.255.255262,142
197131.16.0.0/14131.16.0.1 to 131.19.255.254131.19.255.255262,142
198131.20.0.0/14131.20.0.1 to 131.23.255.254131.23.255.255262,142
199131.24.0.0/14131.24.0.1 to 131.27.255.254131.27.255.255262,142
200131.28.0.0/14131.28.0.1 to 131.31.255.254131.31.255.255262,142
201131.32.0.0/14131.32.0.1 to 131.35.255.254131.35.255.255262,142
202131.36.0.0/14131.36.0.1 to 131.39.255.254131.39.255.255262,142
203131.40.0.0/14131.40.0.1 to 131.43.255.254131.43.255.255262,142
204131.44.0.0/14131.44.0.1 to 131.47.255.254131.47.255.255262,142
205131.48.0.0/14131.48.0.1 to 131.51.255.254131.51.255.255262,142
206131.52.0.0/14131.52.0.1 to 131.55.255.254131.55.255.255262,142
207131.56.0.0/14131.56.0.1 to 131.59.255.254131.59.255.255262,142
208131.60.0.0/14131.60.0.1 to 131.63.255.254131.63.255.255262,142
209131.64.0.0/14131.64.0.1 to 131.67.255.254131.67.255.255262,142
210131.68.0.0/14131.68.0.1 to 131.71.255.254131.71.255.255262,142
211131.72.0.0/14131.72.0.1 to 131.75.255.254131.75.255.255262,142
212131.76.0.0/14131.76.0.1 to 131.79.255.254131.79.255.255262,142
213131.80.0.0/14131.80.0.1 to 131.83.255.254131.83.255.255262,142
214131.84.0.0/14131.84.0.1 to 131.87.255.254131.87.255.255262,142
215131.88.0.0/14131.88.0.1 to 131.91.255.254131.91.255.255262,142
216131.92.0.0/14131.92.0.1 to 131.95.255.254131.95.255.255262,142
217131.96.0.0/14131.96.0.1 to 131.99.255.254131.99.255.255262,142
218131.100.0.0/14131.100.0.1 to 131.103.255.254131.103.255.255262,142
219131.104.0.0/14131.104.0.1 to 131.107.255.254131.107.255.255262,142
220131.108.0.0/14131.108.0.1 to 131.111.255.254131.111.255.255262,142
221131.112.0.0/14131.112.0.1 to 131.115.255.254131.115.255.255262,142
222131.116.0.0/14131.116.0.1 to 131.119.255.254131.119.255.255262,142
223131.120.0.0/14131.120.0.1 to 131.123.255.254131.123.255.255262,142
224131.124.0.0/14131.124.0.1 to 131.127.255.254131.127.255.255262,142
225131.128.0.0/14131.128.0.1 to 131.131.255.254131.131.255.255262,142
226131.132.0.0/14131.132.0.1 to 131.135.255.254131.135.255.255262,142
227131.136.0.0/14131.136.0.1 to 131.139.255.254131.139.255.255262,142
228131.140.0.0/14131.140.0.1 to 131.143.255.254131.143.255.255262,142
229131.144.0.0/14131.144.0.1 to 131.147.255.254131.147.255.255262,142
230131.148.0.0/14131.148.0.1 to 131.151.255.254131.151.255.255262,142
231131.152.0.0/14131.152.0.1 to 131.155.255.254131.155.255.255262,142
232131.156.0.0/14131.156.0.1 to 131.159.255.254131.159.255.255262,142
233131.160.0.0/14131.160.0.1 to 131.163.255.254131.163.255.255262,142
234131.164.0.0/14131.164.0.1 to 131.167.255.254131.167.255.255262,142
235131.168.0.0/14131.168.0.1 to 131.171.255.254131.171.255.255262,142
236131.172.0.0/14131.172.0.1 to 131.175.255.254131.175.255.255262,142
237131.176.0.0/14131.176.0.1 to 131.179.255.254131.179.255.255262,142
238131.180.0.0/14131.180.0.1 to 131.183.255.254131.183.255.255262,142
239131.184.0.0/14131.184.0.1 to 131.187.255.254131.187.255.255262,142
240131.188.0.0/14131.188.0.1 to 131.191.255.254131.191.255.255262,142
241131.192.0.0/14131.192.0.1 to 131.195.255.254131.195.255.255262,142
242131.196.0.0/14131.196.0.1 to 131.199.255.254131.199.255.255262,142
243131.200.0.0/14131.200.0.1 to 131.203.255.254131.203.255.255262,142
244131.204.0.0/14131.204.0.1 to 131.207.255.254131.207.255.255262,142
245131.208.0.0/14131.208.0.1 to 131.211.255.254131.211.255.255262,142
246131.212.0.0/14131.212.0.1 to 131.215.255.254131.215.255.255262,142
247131.216.0.0/14131.216.0.1 to 131.219.255.254131.219.255.255262,142
248131.220.0.0/14131.220.0.1 to 131.223.255.254131.223.255.255262,142
249131.224.0.0/14131.224.0.1 to 131.227.255.254131.227.255.255262,142
250131.228.0.0/14131.228.0.1 to 131.231.255.254131.231.255.255262,142
251131.232.0.0/14131.232.0.1 to 131.235.255.254131.235.255.255262,142
252131.236.0.0/14131.236.0.1 to 131.239.255.254131.239.255.255262,142
253131.240.0.0/14131.240.0.1 to 131.243.255.254131.243.255.255262,142
254131.244.0.0/14131.244.0.1 to 131.247.255.254131.247.255.255262,142
255131.248.0.0/14131.248.0.1 to 131.251.255.254131.251.255.255262,142
256131.252.0.0/14131.252.0.1 to 131.255.255.254131.255.255.255262,142

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.