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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.

Network235.128.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
235.128.0.0
Broadcast address
235.143.255.255
First usable
235.128.0.1
Last usable
235.143.255.254
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
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex EB800000 · Integer 3951034368 to 3952082943
Reverse DNS zones
128.235.in-addr.arpa
129.235.in-addr.arpa
130.235.in-addr.arpa
131.235.in-addr.arpa
132.235.in-addr.arpa
133.235.in-addr.arpa
134.235.in-addr.arpa
135.235.in-addr.arpa
136.235.in-addr.arpa
137.235.in-addr.arpa
138.235.in-addr.arpa
139.235.in-addr.arpa
140.235.in-addr.arpa
141.235.in-addr.arpa
142.235.in-addr.arpa
143.235.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
Address11101011.10000000.00000000.00000000235.128.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network11101011.10000000.00000000.00000000235.128.0.0
Broadcast11101011.10001111.11111111.11111111235.143.255.255
Split into smaller subnets/24
/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)

235.128.0.0/12 makes 4,096 subnets of /24; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1235.128.0.0/24235.128.0.1 to 235.128.0.254235.128.0.255254
2235.128.1.0/24235.128.1.1 to 235.128.1.254235.128.1.255254
3235.128.2.0/24235.128.2.1 to 235.128.2.254235.128.2.255254
4235.128.3.0/24235.128.3.1 to 235.128.3.254235.128.3.255254
5235.128.4.0/24235.128.4.1 to 235.128.4.254235.128.4.255254
6235.128.5.0/24235.128.5.1 to 235.128.5.254235.128.5.255254
7235.128.6.0/24235.128.6.1 to 235.128.6.254235.128.6.255254
8235.128.7.0/24235.128.7.1 to 235.128.7.254235.128.7.255254
9235.128.8.0/24235.128.8.1 to 235.128.8.254235.128.8.255254
10235.128.9.0/24235.128.9.1 to 235.128.9.254235.128.9.255254
11235.128.10.0/24235.128.10.1 to 235.128.10.254235.128.10.255254
12235.128.11.0/24235.128.11.1 to 235.128.11.254235.128.11.255254
13235.128.12.0/24235.128.12.1 to 235.128.12.254235.128.12.255254
14235.128.13.0/24235.128.13.1 to 235.128.13.254235.128.13.255254
15235.128.14.0/24235.128.14.1 to 235.128.14.254235.128.14.255254
16235.128.15.0/24235.128.15.1 to 235.128.15.254235.128.15.255254
17235.128.16.0/24235.128.16.1 to 235.128.16.254235.128.16.255254
18235.128.17.0/24235.128.17.1 to 235.128.17.254235.128.17.255254
19235.128.18.0/24235.128.18.1 to 235.128.18.254235.128.18.255254
20235.128.19.0/24235.128.19.1 to 235.128.19.254235.128.19.255254
21235.128.20.0/24235.128.20.1 to 235.128.20.254235.128.20.255254
22235.128.21.0/24235.128.21.1 to 235.128.21.254235.128.21.255254
23235.128.22.0/24235.128.22.1 to 235.128.22.254235.128.22.255254
24235.128.23.0/24235.128.23.1 to 235.128.23.254235.128.23.255254
25235.128.24.0/24235.128.24.1 to 235.128.24.254235.128.24.255254
26235.128.25.0/24235.128.25.1 to 235.128.25.254235.128.25.255254
27235.128.26.0/24235.128.26.1 to 235.128.26.254235.128.26.255254
28235.128.27.0/24235.128.27.1 to 235.128.27.254235.128.27.255254
29235.128.28.0/24235.128.28.1 to 235.128.28.254235.128.28.255254
30235.128.29.0/24235.128.29.1 to 235.128.29.254235.128.29.255254
31235.128.30.0/24235.128.30.1 to 235.128.30.254235.128.30.255254
32235.128.31.0/24235.128.31.1 to 235.128.31.254235.128.31.255254
33235.128.32.0/24235.128.32.1 to 235.128.32.254235.128.32.255254
34235.128.33.0/24235.128.33.1 to 235.128.33.254235.128.33.255254
35235.128.34.0/24235.128.34.1 to 235.128.34.254235.128.34.255254
36235.128.35.0/24235.128.35.1 to 235.128.35.254235.128.35.255254
37235.128.36.0/24235.128.36.1 to 235.128.36.254235.128.36.255254
38235.128.37.0/24235.128.37.1 to 235.128.37.254235.128.37.255254
39235.128.38.0/24235.128.38.1 to 235.128.38.254235.128.38.255254
40235.128.39.0/24235.128.39.1 to 235.128.39.254235.128.39.255254
41235.128.40.0/24235.128.40.1 to 235.128.40.254235.128.40.255254
42235.128.41.0/24235.128.41.1 to 235.128.41.254235.128.41.255254
43235.128.42.0/24235.128.42.1 to 235.128.42.254235.128.42.255254
44235.128.43.0/24235.128.43.1 to 235.128.43.254235.128.43.255254
45235.128.44.0/24235.128.44.1 to 235.128.44.254235.128.44.255254
46235.128.45.0/24235.128.45.1 to 235.128.45.254235.128.45.255254
47235.128.46.0/24235.128.46.1 to 235.128.46.254235.128.46.255254
48235.128.47.0/24235.128.47.1 to 235.128.47.254235.128.47.255254
49235.128.48.0/24235.128.48.1 to 235.128.48.254235.128.48.255254
50235.128.49.0/24235.128.49.1 to 235.128.49.254235.128.49.255254
51235.128.50.0/24235.128.50.1 to 235.128.50.254235.128.50.255254
52235.128.51.0/24235.128.51.1 to 235.128.51.254235.128.51.255254
53235.128.52.0/24235.128.52.1 to 235.128.52.254235.128.52.255254
54235.128.53.0/24235.128.53.1 to 235.128.53.254235.128.53.255254
55235.128.54.0/24235.128.54.1 to 235.128.54.254235.128.54.255254
56235.128.55.0/24235.128.55.1 to 235.128.55.254235.128.55.255254
57235.128.56.0/24235.128.56.1 to 235.128.56.254235.128.56.255254
58235.128.57.0/24235.128.57.1 to 235.128.57.254235.128.57.255254
59235.128.58.0/24235.128.58.1 to 235.128.58.254235.128.58.255254
60235.128.59.0/24235.128.59.1 to 235.128.59.254235.128.59.255254
61235.128.60.0/24235.128.60.1 to 235.128.60.254235.128.60.255254
62235.128.61.0/24235.128.61.1 to 235.128.61.254235.128.61.255254
63235.128.62.0/24235.128.62.1 to 235.128.62.254235.128.62.255254
64235.128.63.0/24235.128.63.1 to 235.128.63.254235.128.63.255254
65235.128.64.0/24235.128.64.1 to 235.128.64.254235.128.64.255254
66235.128.65.0/24235.128.65.1 to 235.128.65.254235.128.65.255254
67235.128.66.0/24235.128.66.1 to 235.128.66.254235.128.66.255254
68235.128.67.0/24235.128.67.1 to 235.128.67.254235.128.67.255254
69235.128.68.0/24235.128.68.1 to 235.128.68.254235.128.68.255254
70235.128.69.0/24235.128.69.1 to 235.128.69.254235.128.69.255254
71235.128.70.0/24235.128.70.1 to 235.128.70.254235.128.70.255254
72235.128.71.0/24235.128.71.1 to 235.128.71.254235.128.71.255254
73235.128.72.0/24235.128.72.1 to 235.128.72.254235.128.72.255254
74235.128.73.0/24235.128.73.1 to 235.128.73.254235.128.73.255254
75235.128.74.0/24235.128.74.1 to 235.128.74.254235.128.74.255254
76235.128.75.0/24235.128.75.1 to 235.128.75.254235.128.75.255254
77235.128.76.0/24235.128.76.1 to 235.128.76.254235.128.76.255254
78235.128.77.0/24235.128.77.1 to 235.128.77.254235.128.77.255254
79235.128.78.0/24235.128.78.1 to 235.128.78.254235.128.78.255254
80235.128.79.0/24235.128.79.1 to 235.128.79.254235.128.79.255254
81235.128.80.0/24235.128.80.1 to 235.128.80.254235.128.80.255254
82235.128.81.0/24235.128.81.1 to 235.128.81.254235.128.81.255254
83235.128.82.0/24235.128.82.1 to 235.128.82.254235.128.82.255254
84235.128.83.0/24235.128.83.1 to 235.128.83.254235.128.83.255254
85235.128.84.0/24235.128.84.1 to 235.128.84.254235.128.84.255254
86235.128.85.0/24235.128.85.1 to 235.128.85.254235.128.85.255254
87235.128.86.0/24235.128.86.1 to 235.128.86.254235.128.86.255254
88235.128.87.0/24235.128.87.1 to 235.128.87.254235.128.87.255254
89235.128.88.0/24235.128.88.1 to 235.128.88.254235.128.88.255254
90235.128.89.0/24235.128.89.1 to 235.128.89.254235.128.89.255254
91235.128.90.0/24235.128.90.1 to 235.128.90.254235.128.90.255254
92235.128.91.0/24235.128.91.1 to 235.128.91.254235.128.91.255254
93235.128.92.0/24235.128.92.1 to 235.128.92.254235.128.92.255254
94235.128.93.0/24235.128.93.1 to 235.128.93.254235.128.93.255254
95235.128.94.0/24235.128.94.1 to 235.128.94.254235.128.94.255254
96235.128.95.0/24235.128.95.1 to 235.128.95.254235.128.95.255254
97235.128.96.0/24235.128.96.1 to 235.128.96.254235.128.96.255254
98235.128.97.0/24235.128.97.1 to 235.128.97.254235.128.97.255254
99235.128.98.0/24235.128.98.1 to 235.128.98.254235.128.98.255254
100235.128.99.0/24235.128.99.1 to 235.128.99.254235.128.99.255254
101235.128.100.0/24235.128.100.1 to 235.128.100.254235.128.100.255254
102235.128.101.0/24235.128.101.1 to 235.128.101.254235.128.101.255254
103235.128.102.0/24235.128.102.1 to 235.128.102.254235.128.102.255254
104235.128.103.0/24235.128.103.1 to 235.128.103.254235.128.103.255254
105235.128.104.0/24235.128.104.1 to 235.128.104.254235.128.104.255254
106235.128.105.0/24235.128.105.1 to 235.128.105.254235.128.105.255254
107235.128.106.0/24235.128.106.1 to 235.128.106.254235.128.106.255254
108235.128.107.0/24235.128.107.1 to 235.128.107.254235.128.107.255254
109235.128.108.0/24235.128.108.1 to 235.128.108.254235.128.108.255254
110235.128.109.0/24235.128.109.1 to 235.128.109.254235.128.109.255254
111235.128.110.0/24235.128.110.1 to 235.128.110.254235.128.110.255254
112235.128.111.0/24235.128.111.1 to 235.128.111.254235.128.111.255254
113235.128.112.0/24235.128.112.1 to 235.128.112.254235.128.112.255254
114235.128.113.0/24235.128.113.1 to 235.128.113.254235.128.113.255254
115235.128.114.0/24235.128.114.1 to 235.128.114.254235.128.114.255254
116235.128.115.0/24235.128.115.1 to 235.128.115.254235.128.115.255254
117235.128.116.0/24235.128.116.1 to 235.128.116.254235.128.116.255254
118235.128.117.0/24235.128.117.1 to 235.128.117.254235.128.117.255254
119235.128.118.0/24235.128.118.1 to 235.128.118.254235.128.118.255254
120235.128.119.0/24235.128.119.1 to 235.128.119.254235.128.119.255254
121235.128.120.0/24235.128.120.1 to 235.128.120.254235.128.120.255254
122235.128.121.0/24235.128.121.1 to 235.128.121.254235.128.121.255254
123235.128.122.0/24235.128.122.1 to 235.128.122.254235.128.122.255254
124235.128.123.0/24235.128.123.1 to 235.128.123.254235.128.123.255254
125235.128.124.0/24235.128.124.1 to 235.128.124.254235.128.124.255254
126235.128.125.0/24235.128.125.1 to 235.128.125.254235.128.125.255254
127235.128.126.0/24235.128.126.1 to 235.128.126.254235.128.126.255254
128235.128.127.0/24235.128.127.1 to 235.128.127.254235.128.127.255254
129235.128.128.0/24235.128.128.1 to 235.128.128.254235.128.128.255254
130235.128.129.0/24235.128.129.1 to 235.128.129.254235.128.129.255254
131235.128.130.0/24235.128.130.1 to 235.128.130.254235.128.130.255254
132235.128.131.0/24235.128.131.1 to 235.128.131.254235.128.131.255254
133235.128.132.0/24235.128.132.1 to 235.128.132.254235.128.132.255254
134235.128.133.0/24235.128.133.1 to 235.128.133.254235.128.133.255254
135235.128.134.0/24235.128.134.1 to 235.128.134.254235.128.134.255254
136235.128.135.0/24235.128.135.1 to 235.128.135.254235.128.135.255254
137235.128.136.0/24235.128.136.1 to 235.128.136.254235.128.136.255254
138235.128.137.0/24235.128.137.1 to 235.128.137.254235.128.137.255254
139235.128.138.0/24235.128.138.1 to 235.128.138.254235.128.138.255254
140235.128.139.0/24235.128.139.1 to 235.128.139.254235.128.139.255254
141235.128.140.0/24235.128.140.1 to 235.128.140.254235.128.140.255254
142235.128.141.0/24235.128.141.1 to 235.128.141.254235.128.141.255254
143235.128.142.0/24235.128.142.1 to 235.128.142.254235.128.142.255254
144235.128.143.0/24235.128.143.1 to 235.128.143.254235.128.143.255254
145235.128.144.0/24235.128.144.1 to 235.128.144.254235.128.144.255254
146235.128.145.0/24235.128.145.1 to 235.128.145.254235.128.145.255254
147235.128.146.0/24235.128.146.1 to 235.128.146.254235.128.146.255254
148235.128.147.0/24235.128.147.1 to 235.128.147.254235.128.147.255254
149235.128.148.0/24235.128.148.1 to 235.128.148.254235.128.148.255254
150235.128.149.0/24235.128.149.1 to 235.128.149.254235.128.149.255254
151235.128.150.0/24235.128.150.1 to 235.128.150.254235.128.150.255254
152235.128.151.0/24235.128.151.1 to 235.128.151.254235.128.151.255254
153235.128.152.0/24235.128.152.1 to 235.128.152.254235.128.152.255254
154235.128.153.0/24235.128.153.1 to 235.128.153.254235.128.153.255254
155235.128.154.0/24235.128.154.1 to 235.128.154.254235.128.154.255254
156235.128.155.0/24235.128.155.1 to 235.128.155.254235.128.155.255254
157235.128.156.0/24235.128.156.1 to 235.128.156.254235.128.156.255254
158235.128.157.0/24235.128.157.1 to 235.128.157.254235.128.157.255254
159235.128.158.0/24235.128.158.1 to 235.128.158.254235.128.158.255254
160235.128.159.0/24235.128.159.1 to 235.128.159.254235.128.159.255254
161235.128.160.0/24235.128.160.1 to 235.128.160.254235.128.160.255254
162235.128.161.0/24235.128.161.1 to 235.128.161.254235.128.161.255254
163235.128.162.0/24235.128.162.1 to 235.128.162.254235.128.162.255254
164235.128.163.0/24235.128.163.1 to 235.128.163.254235.128.163.255254
165235.128.164.0/24235.128.164.1 to 235.128.164.254235.128.164.255254
166235.128.165.0/24235.128.165.1 to 235.128.165.254235.128.165.255254
167235.128.166.0/24235.128.166.1 to 235.128.166.254235.128.166.255254
168235.128.167.0/24235.128.167.1 to 235.128.167.254235.128.167.255254
169235.128.168.0/24235.128.168.1 to 235.128.168.254235.128.168.255254
170235.128.169.0/24235.128.169.1 to 235.128.169.254235.128.169.255254
171235.128.170.0/24235.128.170.1 to 235.128.170.254235.128.170.255254
172235.128.171.0/24235.128.171.1 to 235.128.171.254235.128.171.255254
173235.128.172.0/24235.128.172.1 to 235.128.172.254235.128.172.255254
174235.128.173.0/24235.128.173.1 to 235.128.173.254235.128.173.255254
175235.128.174.0/24235.128.174.1 to 235.128.174.254235.128.174.255254
176235.128.175.0/24235.128.175.1 to 235.128.175.254235.128.175.255254
177235.128.176.0/24235.128.176.1 to 235.128.176.254235.128.176.255254
178235.128.177.0/24235.128.177.1 to 235.128.177.254235.128.177.255254
179235.128.178.0/24235.128.178.1 to 235.128.178.254235.128.178.255254
180235.128.179.0/24235.128.179.1 to 235.128.179.254235.128.179.255254
181235.128.180.0/24235.128.180.1 to 235.128.180.254235.128.180.255254
182235.128.181.0/24235.128.181.1 to 235.128.181.254235.128.181.255254
183235.128.182.0/24235.128.182.1 to 235.128.182.254235.128.182.255254
184235.128.183.0/24235.128.183.1 to 235.128.183.254235.128.183.255254
185235.128.184.0/24235.128.184.1 to 235.128.184.254235.128.184.255254
186235.128.185.0/24235.128.185.1 to 235.128.185.254235.128.185.255254
187235.128.186.0/24235.128.186.1 to 235.128.186.254235.128.186.255254
188235.128.187.0/24235.128.187.1 to 235.128.187.254235.128.187.255254
189235.128.188.0/24235.128.188.1 to 235.128.188.254235.128.188.255254
190235.128.189.0/24235.128.189.1 to 235.128.189.254235.128.189.255254
191235.128.190.0/24235.128.190.1 to 235.128.190.254235.128.190.255254
192235.128.191.0/24235.128.191.1 to 235.128.191.254235.128.191.255254
193235.128.192.0/24235.128.192.1 to 235.128.192.254235.128.192.255254
194235.128.193.0/24235.128.193.1 to 235.128.193.254235.128.193.255254
195235.128.194.0/24235.128.194.1 to 235.128.194.254235.128.194.255254
196235.128.195.0/24235.128.195.1 to 235.128.195.254235.128.195.255254
197235.128.196.0/24235.128.196.1 to 235.128.196.254235.128.196.255254
198235.128.197.0/24235.128.197.1 to 235.128.197.254235.128.197.255254
199235.128.198.0/24235.128.198.1 to 235.128.198.254235.128.198.255254
200235.128.199.0/24235.128.199.1 to 235.128.199.254235.128.199.255254
201235.128.200.0/24235.128.200.1 to 235.128.200.254235.128.200.255254
202235.128.201.0/24235.128.201.1 to 235.128.201.254235.128.201.255254
203235.128.202.0/24235.128.202.1 to 235.128.202.254235.128.202.255254
204235.128.203.0/24235.128.203.1 to 235.128.203.254235.128.203.255254
205235.128.204.0/24235.128.204.1 to 235.128.204.254235.128.204.255254
206235.128.205.0/24235.128.205.1 to 235.128.205.254235.128.205.255254
207235.128.206.0/24235.128.206.1 to 235.128.206.254235.128.206.255254
208235.128.207.0/24235.128.207.1 to 235.128.207.254235.128.207.255254
209235.128.208.0/24235.128.208.1 to 235.128.208.254235.128.208.255254
210235.128.209.0/24235.128.209.1 to 235.128.209.254235.128.209.255254
211235.128.210.0/24235.128.210.1 to 235.128.210.254235.128.210.255254
212235.128.211.0/24235.128.211.1 to 235.128.211.254235.128.211.255254
213235.128.212.0/24235.128.212.1 to 235.128.212.254235.128.212.255254
214235.128.213.0/24235.128.213.1 to 235.128.213.254235.128.213.255254
215235.128.214.0/24235.128.214.1 to 235.128.214.254235.128.214.255254
216235.128.215.0/24235.128.215.1 to 235.128.215.254235.128.215.255254
217235.128.216.0/24235.128.216.1 to 235.128.216.254235.128.216.255254
218235.128.217.0/24235.128.217.1 to 235.128.217.254235.128.217.255254
219235.128.218.0/24235.128.218.1 to 235.128.218.254235.128.218.255254
220235.128.219.0/24235.128.219.1 to 235.128.219.254235.128.219.255254
221235.128.220.0/24235.128.220.1 to 235.128.220.254235.128.220.255254
222235.128.221.0/24235.128.221.1 to 235.128.221.254235.128.221.255254
223235.128.222.0/24235.128.222.1 to 235.128.222.254235.128.222.255254
224235.128.223.0/24235.128.223.1 to 235.128.223.254235.128.223.255254
225235.128.224.0/24235.128.224.1 to 235.128.224.254235.128.224.255254
226235.128.225.0/24235.128.225.1 to 235.128.225.254235.128.225.255254
227235.128.226.0/24235.128.226.1 to 235.128.226.254235.128.226.255254
228235.128.227.0/24235.128.227.1 to 235.128.227.254235.128.227.255254
229235.128.228.0/24235.128.228.1 to 235.128.228.254235.128.228.255254
230235.128.229.0/24235.128.229.1 to 235.128.229.254235.128.229.255254
231235.128.230.0/24235.128.230.1 to 235.128.230.254235.128.230.255254
232235.128.231.0/24235.128.231.1 to 235.128.231.254235.128.231.255254
233235.128.232.0/24235.128.232.1 to 235.128.232.254235.128.232.255254
234235.128.233.0/24235.128.233.1 to 235.128.233.254235.128.233.255254
235235.128.234.0/24235.128.234.1 to 235.128.234.254235.128.234.255254
236235.128.235.0/24235.128.235.1 to 235.128.235.254235.128.235.255254
237235.128.236.0/24235.128.236.1 to 235.128.236.254235.128.236.255254
238235.128.237.0/24235.128.237.1 to 235.128.237.254235.128.237.255254
239235.128.238.0/24235.128.238.1 to 235.128.238.254235.128.238.255254
240235.128.239.0/24235.128.239.1 to 235.128.239.254235.128.239.255254
241235.128.240.0/24235.128.240.1 to 235.128.240.254235.128.240.255254
242235.128.241.0/24235.128.241.1 to 235.128.241.254235.128.241.255254
243235.128.242.0/24235.128.242.1 to 235.128.242.254235.128.242.255254
244235.128.243.0/24235.128.243.1 to 235.128.243.254235.128.243.255254
245235.128.244.0/24235.128.244.1 to 235.128.244.254235.128.244.255254
246235.128.245.0/24235.128.245.1 to 235.128.245.254235.128.245.255254
247235.128.246.0/24235.128.246.1 to 235.128.246.254235.128.246.255254
248235.128.247.0/24235.128.247.1 to 235.128.247.254235.128.247.255254
249235.128.248.0/24235.128.248.1 to 235.128.248.254235.128.248.255254
250235.128.249.0/24235.128.249.1 to 235.128.249.254235.128.249.255254
251235.128.250.0/24235.128.250.1 to 235.128.250.254235.128.250.255254
252235.128.251.0/24235.128.251.1 to 235.128.251.254235.128.251.255254
253235.128.252.0/24235.128.252.1 to 235.128.252.254235.128.252.255254
254235.128.253.0/24235.128.253.1 to 235.128.253.254235.128.253.255254
255235.128.254.0/24235.128.254.1 to 235.128.254.254235.128.254.255254
256235.128.255.0/24235.128.255.1 to 235.128.255.254235.128.255.255254

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.