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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.

Network245.80.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
245.80.0.0
Broadcast address
245.95.255.255
First usable
245.80.0.1
Last usable
245.95.255.254
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
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex F5500000 · Integer 4115660800 to 4116709375
Reverse DNS zones
80.245.in-addr.arpa
81.245.in-addr.arpa
82.245.in-addr.arpa
83.245.in-addr.arpa
84.245.in-addr.arpa
85.245.in-addr.arpa
86.245.in-addr.arpa
87.245.in-addr.arpa
88.245.in-addr.arpa
89.245.in-addr.arpa
90.245.in-addr.arpa
91.245.in-addr.arpa
92.245.in-addr.arpa
93.245.in-addr.arpa
94.245.in-addr.arpa
95.245.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
Address11110101.01010000.00000000.00000000245.80.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network11110101.01010000.00000000.00000000245.80.0.0
Broadcast11110101.01011111.11111111.11111111245.95.255.255
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)

245.80.0.0/12 makes 4,096 subnets of /24; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1245.80.0.0/24245.80.0.1 to 245.80.0.254245.80.0.255254
2245.80.1.0/24245.80.1.1 to 245.80.1.254245.80.1.255254
3245.80.2.0/24245.80.2.1 to 245.80.2.254245.80.2.255254
4245.80.3.0/24245.80.3.1 to 245.80.3.254245.80.3.255254
5245.80.4.0/24245.80.4.1 to 245.80.4.254245.80.4.255254
6245.80.5.0/24245.80.5.1 to 245.80.5.254245.80.5.255254
7245.80.6.0/24245.80.6.1 to 245.80.6.254245.80.6.255254
8245.80.7.0/24245.80.7.1 to 245.80.7.254245.80.7.255254
9245.80.8.0/24245.80.8.1 to 245.80.8.254245.80.8.255254
10245.80.9.0/24245.80.9.1 to 245.80.9.254245.80.9.255254
11245.80.10.0/24245.80.10.1 to 245.80.10.254245.80.10.255254
12245.80.11.0/24245.80.11.1 to 245.80.11.254245.80.11.255254
13245.80.12.0/24245.80.12.1 to 245.80.12.254245.80.12.255254
14245.80.13.0/24245.80.13.1 to 245.80.13.254245.80.13.255254
15245.80.14.0/24245.80.14.1 to 245.80.14.254245.80.14.255254
16245.80.15.0/24245.80.15.1 to 245.80.15.254245.80.15.255254
17245.80.16.0/24245.80.16.1 to 245.80.16.254245.80.16.255254
18245.80.17.0/24245.80.17.1 to 245.80.17.254245.80.17.255254
19245.80.18.0/24245.80.18.1 to 245.80.18.254245.80.18.255254
20245.80.19.0/24245.80.19.1 to 245.80.19.254245.80.19.255254
21245.80.20.0/24245.80.20.1 to 245.80.20.254245.80.20.255254
22245.80.21.0/24245.80.21.1 to 245.80.21.254245.80.21.255254
23245.80.22.0/24245.80.22.1 to 245.80.22.254245.80.22.255254
24245.80.23.0/24245.80.23.1 to 245.80.23.254245.80.23.255254
25245.80.24.0/24245.80.24.1 to 245.80.24.254245.80.24.255254
26245.80.25.0/24245.80.25.1 to 245.80.25.254245.80.25.255254
27245.80.26.0/24245.80.26.1 to 245.80.26.254245.80.26.255254
28245.80.27.0/24245.80.27.1 to 245.80.27.254245.80.27.255254
29245.80.28.0/24245.80.28.1 to 245.80.28.254245.80.28.255254
30245.80.29.0/24245.80.29.1 to 245.80.29.254245.80.29.255254
31245.80.30.0/24245.80.30.1 to 245.80.30.254245.80.30.255254
32245.80.31.0/24245.80.31.1 to 245.80.31.254245.80.31.255254
33245.80.32.0/24245.80.32.1 to 245.80.32.254245.80.32.255254
34245.80.33.0/24245.80.33.1 to 245.80.33.254245.80.33.255254
35245.80.34.0/24245.80.34.1 to 245.80.34.254245.80.34.255254
36245.80.35.0/24245.80.35.1 to 245.80.35.254245.80.35.255254
37245.80.36.0/24245.80.36.1 to 245.80.36.254245.80.36.255254
38245.80.37.0/24245.80.37.1 to 245.80.37.254245.80.37.255254
39245.80.38.0/24245.80.38.1 to 245.80.38.254245.80.38.255254
40245.80.39.0/24245.80.39.1 to 245.80.39.254245.80.39.255254
41245.80.40.0/24245.80.40.1 to 245.80.40.254245.80.40.255254
42245.80.41.0/24245.80.41.1 to 245.80.41.254245.80.41.255254
43245.80.42.0/24245.80.42.1 to 245.80.42.254245.80.42.255254
44245.80.43.0/24245.80.43.1 to 245.80.43.254245.80.43.255254
45245.80.44.0/24245.80.44.1 to 245.80.44.254245.80.44.255254
46245.80.45.0/24245.80.45.1 to 245.80.45.254245.80.45.255254
47245.80.46.0/24245.80.46.1 to 245.80.46.254245.80.46.255254
48245.80.47.0/24245.80.47.1 to 245.80.47.254245.80.47.255254
49245.80.48.0/24245.80.48.1 to 245.80.48.254245.80.48.255254
50245.80.49.0/24245.80.49.1 to 245.80.49.254245.80.49.255254
51245.80.50.0/24245.80.50.1 to 245.80.50.254245.80.50.255254
52245.80.51.0/24245.80.51.1 to 245.80.51.254245.80.51.255254
53245.80.52.0/24245.80.52.1 to 245.80.52.254245.80.52.255254
54245.80.53.0/24245.80.53.1 to 245.80.53.254245.80.53.255254
55245.80.54.0/24245.80.54.1 to 245.80.54.254245.80.54.255254
56245.80.55.0/24245.80.55.1 to 245.80.55.254245.80.55.255254
57245.80.56.0/24245.80.56.1 to 245.80.56.254245.80.56.255254
58245.80.57.0/24245.80.57.1 to 245.80.57.254245.80.57.255254
59245.80.58.0/24245.80.58.1 to 245.80.58.254245.80.58.255254
60245.80.59.0/24245.80.59.1 to 245.80.59.254245.80.59.255254
61245.80.60.0/24245.80.60.1 to 245.80.60.254245.80.60.255254
62245.80.61.0/24245.80.61.1 to 245.80.61.254245.80.61.255254
63245.80.62.0/24245.80.62.1 to 245.80.62.254245.80.62.255254
64245.80.63.0/24245.80.63.1 to 245.80.63.254245.80.63.255254
65245.80.64.0/24245.80.64.1 to 245.80.64.254245.80.64.255254
66245.80.65.0/24245.80.65.1 to 245.80.65.254245.80.65.255254
67245.80.66.0/24245.80.66.1 to 245.80.66.254245.80.66.255254
68245.80.67.0/24245.80.67.1 to 245.80.67.254245.80.67.255254
69245.80.68.0/24245.80.68.1 to 245.80.68.254245.80.68.255254
70245.80.69.0/24245.80.69.1 to 245.80.69.254245.80.69.255254
71245.80.70.0/24245.80.70.1 to 245.80.70.254245.80.70.255254
72245.80.71.0/24245.80.71.1 to 245.80.71.254245.80.71.255254
73245.80.72.0/24245.80.72.1 to 245.80.72.254245.80.72.255254
74245.80.73.0/24245.80.73.1 to 245.80.73.254245.80.73.255254
75245.80.74.0/24245.80.74.1 to 245.80.74.254245.80.74.255254
76245.80.75.0/24245.80.75.1 to 245.80.75.254245.80.75.255254
77245.80.76.0/24245.80.76.1 to 245.80.76.254245.80.76.255254
78245.80.77.0/24245.80.77.1 to 245.80.77.254245.80.77.255254
79245.80.78.0/24245.80.78.1 to 245.80.78.254245.80.78.255254
80245.80.79.0/24245.80.79.1 to 245.80.79.254245.80.79.255254
81245.80.80.0/24245.80.80.1 to 245.80.80.254245.80.80.255254
82245.80.81.0/24245.80.81.1 to 245.80.81.254245.80.81.255254
83245.80.82.0/24245.80.82.1 to 245.80.82.254245.80.82.255254
84245.80.83.0/24245.80.83.1 to 245.80.83.254245.80.83.255254
85245.80.84.0/24245.80.84.1 to 245.80.84.254245.80.84.255254
86245.80.85.0/24245.80.85.1 to 245.80.85.254245.80.85.255254
87245.80.86.0/24245.80.86.1 to 245.80.86.254245.80.86.255254
88245.80.87.0/24245.80.87.1 to 245.80.87.254245.80.87.255254
89245.80.88.0/24245.80.88.1 to 245.80.88.254245.80.88.255254
90245.80.89.0/24245.80.89.1 to 245.80.89.254245.80.89.255254
91245.80.90.0/24245.80.90.1 to 245.80.90.254245.80.90.255254
92245.80.91.0/24245.80.91.1 to 245.80.91.254245.80.91.255254
93245.80.92.0/24245.80.92.1 to 245.80.92.254245.80.92.255254
94245.80.93.0/24245.80.93.1 to 245.80.93.254245.80.93.255254
95245.80.94.0/24245.80.94.1 to 245.80.94.254245.80.94.255254
96245.80.95.0/24245.80.95.1 to 245.80.95.254245.80.95.255254
97245.80.96.0/24245.80.96.1 to 245.80.96.254245.80.96.255254
98245.80.97.0/24245.80.97.1 to 245.80.97.254245.80.97.255254
99245.80.98.0/24245.80.98.1 to 245.80.98.254245.80.98.255254
100245.80.99.0/24245.80.99.1 to 245.80.99.254245.80.99.255254
101245.80.100.0/24245.80.100.1 to 245.80.100.254245.80.100.255254
102245.80.101.0/24245.80.101.1 to 245.80.101.254245.80.101.255254
103245.80.102.0/24245.80.102.1 to 245.80.102.254245.80.102.255254
104245.80.103.0/24245.80.103.1 to 245.80.103.254245.80.103.255254
105245.80.104.0/24245.80.104.1 to 245.80.104.254245.80.104.255254
106245.80.105.0/24245.80.105.1 to 245.80.105.254245.80.105.255254
107245.80.106.0/24245.80.106.1 to 245.80.106.254245.80.106.255254
108245.80.107.0/24245.80.107.1 to 245.80.107.254245.80.107.255254
109245.80.108.0/24245.80.108.1 to 245.80.108.254245.80.108.255254
110245.80.109.0/24245.80.109.1 to 245.80.109.254245.80.109.255254
111245.80.110.0/24245.80.110.1 to 245.80.110.254245.80.110.255254
112245.80.111.0/24245.80.111.1 to 245.80.111.254245.80.111.255254
113245.80.112.0/24245.80.112.1 to 245.80.112.254245.80.112.255254
114245.80.113.0/24245.80.113.1 to 245.80.113.254245.80.113.255254
115245.80.114.0/24245.80.114.1 to 245.80.114.254245.80.114.255254
116245.80.115.0/24245.80.115.1 to 245.80.115.254245.80.115.255254
117245.80.116.0/24245.80.116.1 to 245.80.116.254245.80.116.255254
118245.80.117.0/24245.80.117.1 to 245.80.117.254245.80.117.255254
119245.80.118.0/24245.80.118.1 to 245.80.118.254245.80.118.255254
120245.80.119.0/24245.80.119.1 to 245.80.119.254245.80.119.255254
121245.80.120.0/24245.80.120.1 to 245.80.120.254245.80.120.255254
122245.80.121.0/24245.80.121.1 to 245.80.121.254245.80.121.255254
123245.80.122.0/24245.80.122.1 to 245.80.122.254245.80.122.255254
124245.80.123.0/24245.80.123.1 to 245.80.123.254245.80.123.255254
125245.80.124.0/24245.80.124.1 to 245.80.124.254245.80.124.255254
126245.80.125.0/24245.80.125.1 to 245.80.125.254245.80.125.255254
127245.80.126.0/24245.80.126.1 to 245.80.126.254245.80.126.255254
128245.80.127.0/24245.80.127.1 to 245.80.127.254245.80.127.255254
129245.80.128.0/24245.80.128.1 to 245.80.128.254245.80.128.255254
130245.80.129.0/24245.80.129.1 to 245.80.129.254245.80.129.255254
131245.80.130.0/24245.80.130.1 to 245.80.130.254245.80.130.255254
132245.80.131.0/24245.80.131.1 to 245.80.131.254245.80.131.255254
133245.80.132.0/24245.80.132.1 to 245.80.132.254245.80.132.255254
134245.80.133.0/24245.80.133.1 to 245.80.133.254245.80.133.255254
135245.80.134.0/24245.80.134.1 to 245.80.134.254245.80.134.255254
136245.80.135.0/24245.80.135.1 to 245.80.135.254245.80.135.255254
137245.80.136.0/24245.80.136.1 to 245.80.136.254245.80.136.255254
138245.80.137.0/24245.80.137.1 to 245.80.137.254245.80.137.255254
139245.80.138.0/24245.80.138.1 to 245.80.138.254245.80.138.255254
140245.80.139.0/24245.80.139.1 to 245.80.139.254245.80.139.255254
141245.80.140.0/24245.80.140.1 to 245.80.140.254245.80.140.255254
142245.80.141.0/24245.80.141.1 to 245.80.141.254245.80.141.255254
143245.80.142.0/24245.80.142.1 to 245.80.142.254245.80.142.255254
144245.80.143.0/24245.80.143.1 to 245.80.143.254245.80.143.255254
145245.80.144.0/24245.80.144.1 to 245.80.144.254245.80.144.255254
146245.80.145.0/24245.80.145.1 to 245.80.145.254245.80.145.255254
147245.80.146.0/24245.80.146.1 to 245.80.146.254245.80.146.255254
148245.80.147.0/24245.80.147.1 to 245.80.147.254245.80.147.255254
149245.80.148.0/24245.80.148.1 to 245.80.148.254245.80.148.255254
150245.80.149.0/24245.80.149.1 to 245.80.149.254245.80.149.255254
151245.80.150.0/24245.80.150.1 to 245.80.150.254245.80.150.255254
152245.80.151.0/24245.80.151.1 to 245.80.151.254245.80.151.255254
153245.80.152.0/24245.80.152.1 to 245.80.152.254245.80.152.255254
154245.80.153.0/24245.80.153.1 to 245.80.153.254245.80.153.255254
155245.80.154.0/24245.80.154.1 to 245.80.154.254245.80.154.255254
156245.80.155.0/24245.80.155.1 to 245.80.155.254245.80.155.255254
157245.80.156.0/24245.80.156.1 to 245.80.156.254245.80.156.255254
158245.80.157.0/24245.80.157.1 to 245.80.157.254245.80.157.255254
159245.80.158.0/24245.80.158.1 to 245.80.158.254245.80.158.255254
160245.80.159.0/24245.80.159.1 to 245.80.159.254245.80.159.255254
161245.80.160.0/24245.80.160.1 to 245.80.160.254245.80.160.255254
162245.80.161.0/24245.80.161.1 to 245.80.161.254245.80.161.255254
163245.80.162.0/24245.80.162.1 to 245.80.162.254245.80.162.255254
164245.80.163.0/24245.80.163.1 to 245.80.163.254245.80.163.255254
165245.80.164.0/24245.80.164.1 to 245.80.164.254245.80.164.255254
166245.80.165.0/24245.80.165.1 to 245.80.165.254245.80.165.255254
167245.80.166.0/24245.80.166.1 to 245.80.166.254245.80.166.255254
168245.80.167.0/24245.80.167.1 to 245.80.167.254245.80.167.255254
169245.80.168.0/24245.80.168.1 to 245.80.168.254245.80.168.255254
170245.80.169.0/24245.80.169.1 to 245.80.169.254245.80.169.255254
171245.80.170.0/24245.80.170.1 to 245.80.170.254245.80.170.255254
172245.80.171.0/24245.80.171.1 to 245.80.171.254245.80.171.255254
173245.80.172.0/24245.80.172.1 to 245.80.172.254245.80.172.255254
174245.80.173.0/24245.80.173.1 to 245.80.173.254245.80.173.255254
175245.80.174.0/24245.80.174.1 to 245.80.174.254245.80.174.255254
176245.80.175.0/24245.80.175.1 to 245.80.175.254245.80.175.255254
177245.80.176.0/24245.80.176.1 to 245.80.176.254245.80.176.255254
178245.80.177.0/24245.80.177.1 to 245.80.177.254245.80.177.255254
179245.80.178.0/24245.80.178.1 to 245.80.178.254245.80.178.255254
180245.80.179.0/24245.80.179.1 to 245.80.179.254245.80.179.255254
181245.80.180.0/24245.80.180.1 to 245.80.180.254245.80.180.255254
182245.80.181.0/24245.80.181.1 to 245.80.181.254245.80.181.255254
183245.80.182.0/24245.80.182.1 to 245.80.182.254245.80.182.255254
184245.80.183.0/24245.80.183.1 to 245.80.183.254245.80.183.255254
185245.80.184.0/24245.80.184.1 to 245.80.184.254245.80.184.255254
186245.80.185.0/24245.80.185.1 to 245.80.185.254245.80.185.255254
187245.80.186.0/24245.80.186.1 to 245.80.186.254245.80.186.255254
188245.80.187.0/24245.80.187.1 to 245.80.187.254245.80.187.255254
189245.80.188.0/24245.80.188.1 to 245.80.188.254245.80.188.255254
190245.80.189.0/24245.80.189.1 to 245.80.189.254245.80.189.255254
191245.80.190.0/24245.80.190.1 to 245.80.190.254245.80.190.255254
192245.80.191.0/24245.80.191.1 to 245.80.191.254245.80.191.255254
193245.80.192.0/24245.80.192.1 to 245.80.192.254245.80.192.255254
194245.80.193.0/24245.80.193.1 to 245.80.193.254245.80.193.255254
195245.80.194.0/24245.80.194.1 to 245.80.194.254245.80.194.255254
196245.80.195.0/24245.80.195.1 to 245.80.195.254245.80.195.255254
197245.80.196.0/24245.80.196.1 to 245.80.196.254245.80.196.255254
198245.80.197.0/24245.80.197.1 to 245.80.197.254245.80.197.255254
199245.80.198.0/24245.80.198.1 to 245.80.198.254245.80.198.255254
200245.80.199.0/24245.80.199.1 to 245.80.199.254245.80.199.255254
201245.80.200.0/24245.80.200.1 to 245.80.200.254245.80.200.255254
202245.80.201.0/24245.80.201.1 to 245.80.201.254245.80.201.255254
203245.80.202.0/24245.80.202.1 to 245.80.202.254245.80.202.255254
204245.80.203.0/24245.80.203.1 to 245.80.203.254245.80.203.255254
205245.80.204.0/24245.80.204.1 to 245.80.204.254245.80.204.255254
206245.80.205.0/24245.80.205.1 to 245.80.205.254245.80.205.255254
207245.80.206.0/24245.80.206.1 to 245.80.206.254245.80.206.255254
208245.80.207.0/24245.80.207.1 to 245.80.207.254245.80.207.255254
209245.80.208.0/24245.80.208.1 to 245.80.208.254245.80.208.255254
210245.80.209.0/24245.80.209.1 to 245.80.209.254245.80.209.255254
211245.80.210.0/24245.80.210.1 to 245.80.210.254245.80.210.255254
212245.80.211.0/24245.80.211.1 to 245.80.211.254245.80.211.255254
213245.80.212.0/24245.80.212.1 to 245.80.212.254245.80.212.255254
214245.80.213.0/24245.80.213.1 to 245.80.213.254245.80.213.255254
215245.80.214.0/24245.80.214.1 to 245.80.214.254245.80.214.255254
216245.80.215.0/24245.80.215.1 to 245.80.215.254245.80.215.255254
217245.80.216.0/24245.80.216.1 to 245.80.216.254245.80.216.255254
218245.80.217.0/24245.80.217.1 to 245.80.217.254245.80.217.255254
219245.80.218.0/24245.80.218.1 to 245.80.218.254245.80.218.255254
220245.80.219.0/24245.80.219.1 to 245.80.219.254245.80.219.255254
221245.80.220.0/24245.80.220.1 to 245.80.220.254245.80.220.255254
222245.80.221.0/24245.80.221.1 to 245.80.221.254245.80.221.255254
223245.80.222.0/24245.80.222.1 to 245.80.222.254245.80.222.255254
224245.80.223.0/24245.80.223.1 to 245.80.223.254245.80.223.255254
225245.80.224.0/24245.80.224.1 to 245.80.224.254245.80.224.255254
226245.80.225.0/24245.80.225.1 to 245.80.225.254245.80.225.255254
227245.80.226.0/24245.80.226.1 to 245.80.226.254245.80.226.255254
228245.80.227.0/24245.80.227.1 to 245.80.227.254245.80.227.255254
229245.80.228.0/24245.80.228.1 to 245.80.228.254245.80.228.255254
230245.80.229.0/24245.80.229.1 to 245.80.229.254245.80.229.255254
231245.80.230.0/24245.80.230.1 to 245.80.230.254245.80.230.255254
232245.80.231.0/24245.80.231.1 to 245.80.231.254245.80.231.255254
233245.80.232.0/24245.80.232.1 to 245.80.232.254245.80.232.255254
234245.80.233.0/24245.80.233.1 to 245.80.233.254245.80.233.255254
235245.80.234.0/24245.80.234.1 to 245.80.234.254245.80.234.255254
236245.80.235.0/24245.80.235.1 to 245.80.235.254245.80.235.255254
237245.80.236.0/24245.80.236.1 to 245.80.236.254245.80.236.255254
238245.80.237.0/24245.80.237.1 to 245.80.237.254245.80.237.255254
239245.80.238.0/24245.80.238.1 to 245.80.238.254245.80.238.255254
240245.80.239.0/24245.80.239.1 to 245.80.239.254245.80.239.255254
241245.80.240.0/24245.80.240.1 to 245.80.240.254245.80.240.255254
242245.80.241.0/24245.80.241.1 to 245.80.241.254245.80.241.255254
243245.80.242.0/24245.80.242.1 to 245.80.242.254245.80.242.255254
244245.80.243.0/24245.80.243.1 to 245.80.243.254245.80.243.255254
245245.80.244.0/24245.80.244.1 to 245.80.244.254245.80.244.255254
246245.80.245.0/24245.80.245.1 to 245.80.245.254245.80.245.255254
247245.80.246.0/24245.80.246.1 to 245.80.246.254245.80.246.255254
248245.80.247.0/24245.80.247.1 to 245.80.247.254245.80.247.255254
249245.80.248.0/24245.80.248.1 to 245.80.248.254245.80.248.255254
250245.80.249.0/24245.80.249.1 to 245.80.249.254245.80.249.255254
251245.80.250.0/24245.80.250.1 to 245.80.250.254245.80.250.255254
252245.80.251.0/24245.80.251.1 to 245.80.251.254245.80.251.255254
253245.80.252.0/24245.80.252.1 to 245.80.252.254245.80.252.255254
254245.80.253.0/24245.80.253.1 to 245.80.253.254245.80.253.255254
255245.80.254.0/24245.80.254.1 to 245.80.254.254245.80.254.255254
256245.80.255.0/24245.80.255.1 to 245.80.255.254245.80.255.255254

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.