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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.

Network104.239.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
104.239.0.0
Broadcast address
104.239.255.255
First usable
104.239.0.1
Last usable
104.239.255.254
Usable hosts
65,534 (65,536 less the network and broadcast addresses)
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255 (Cisco ACLs, OSPF)
Prefix length
/16
Type
Public public
Old class
A (default /8)
As numbers
Hex 68EF0000 · Integer 1760493568 to 1760559103
Reverse DNS zone
239.104.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01101000.11101111..00000000.00000000104.239.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network01101000.11101111..00000000.00000000104.239.0.0
Broadcast01101000.11101111..11111111.11111111104.239.255.255
Split into smaller subnets/24
/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

104.239.0.0/16 makes 256 subnets of /24.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1104.239.0.0/24104.239.0.1 to 104.239.0.254104.239.0.255254
2104.239.1.0/24104.239.1.1 to 104.239.1.254104.239.1.255254
3104.239.2.0/24104.239.2.1 to 104.239.2.254104.239.2.255254
4104.239.3.0/24104.239.3.1 to 104.239.3.254104.239.3.255254
5104.239.4.0/24104.239.4.1 to 104.239.4.254104.239.4.255254
6104.239.5.0/24104.239.5.1 to 104.239.5.254104.239.5.255254
7104.239.6.0/24104.239.6.1 to 104.239.6.254104.239.6.255254
8104.239.7.0/24104.239.7.1 to 104.239.7.254104.239.7.255254
9104.239.8.0/24104.239.8.1 to 104.239.8.254104.239.8.255254
10104.239.9.0/24104.239.9.1 to 104.239.9.254104.239.9.255254
11104.239.10.0/24104.239.10.1 to 104.239.10.254104.239.10.255254
12104.239.11.0/24104.239.11.1 to 104.239.11.254104.239.11.255254
13104.239.12.0/24104.239.12.1 to 104.239.12.254104.239.12.255254
14104.239.13.0/24104.239.13.1 to 104.239.13.254104.239.13.255254
15104.239.14.0/24104.239.14.1 to 104.239.14.254104.239.14.255254
16104.239.15.0/24104.239.15.1 to 104.239.15.254104.239.15.255254
17104.239.16.0/24104.239.16.1 to 104.239.16.254104.239.16.255254
18104.239.17.0/24104.239.17.1 to 104.239.17.254104.239.17.255254
19104.239.18.0/24104.239.18.1 to 104.239.18.254104.239.18.255254
20104.239.19.0/24104.239.19.1 to 104.239.19.254104.239.19.255254
21104.239.20.0/24104.239.20.1 to 104.239.20.254104.239.20.255254
22104.239.21.0/24104.239.21.1 to 104.239.21.254104.239.21.255254
23104.239.22.0/24104.239.22.1 to 104.239.22.254104.239.22.255254
24104.239.23.0/24104.239.23.1 to 104.239.23.254104.239.23.255254
25104.239.24.0/24104.239.24.1 to 104.239.24.254104.239.24.255254
26104.239.25.0/24104.239.25.1 to 104.239.25.254104.239.25.255254
27104.239.26.0/24104.239.26.1 to 104.239.26.254104.239.26.255254
28104.239.27.0/24104.239.27.1 to 104.239.27.254104.239.27.255254
29104.239.28.0/24104.239.28.1 to 104.239.28.254104.239.28.255254
30104.239.29.0/24104.239.29.1 to 104.239.29.254104.239.29.255254
31104.239.30.0/24104.239.30.1 to 104.239.30.254104.239.30.255254
32104.239.31.0/24104.239.31.1 to 104.239.31.254104.239.31.255254
33104.239.32.0/24104.239.32.1 to 104.239.32.254104.239.32.255254
34104.239.33.0/24104.239.33.1 to 104.239.33.254104.239.33.255254
35104.239.34.0/24104.239.34.1 to 104.239.34.254104.239.34.255254
36104.239.35.0/24104.239.35.1 to 104.239.35.254104.239.35.255254
37104.239.36.0/24104.239.36.1 to 104.239.36.254104.239.36.255254
38104.239.37.0/24104.239.37.1 to 104.239.37.254104.239.37.255254
39104.239.38.0/24104.239.38.1 to 104.239.38.254104.239.38.255254
40104.239.39.0/24104.239.39.1 to 104.239.39.254104.239.39.255254
41104.239.40.0/24104.239.40.1 to 104.239.40.254104.239.40.255254
42104.239.41.0/24104.239.41.1 to 104.239.41.254104.239.41.255254
43104.239.42.0/24104.239.42.1 to 104.239.42.254104.239.42.255254
44104.239.43.0/24104.239.43.1 to 104.239.43.254104.239.43.255254
45104.239.44.0/24104.239.44.1 to 104.239.44.254104.239.44.255254
46104.239.45.0/24104.239.45.1 to 104.239.45.254104.239.45.255254
47104.239.46.0/24104.239.46.1 to 104.239.46.254104.239.46.255254
48104.239.47.0/24104.239.47.1 to 104.239.47.254104.239.47.255254
49104.239.48.0/24104.239.48.1 to 104.239.48.254104.239.48.255254
50104.239.49.0/24104.239.49.1 to 104.239.49.254104.239.49.255254
51104.239.50.0/24104.239.50.1 to 104.239.50.254104.239.50.255254
52104.239.51.0/24104.239.51.1 to 104.239.51.254104.239.51.255254
53104.239.52.0/24104.239.52.1 to 104.239.52.254104.239.52.255254
54104.239.53.0/24104.239.53.1 to 104.239.53.254104.239.53.255254
55104.239.54.0/24104.239.54.1 to 104.239.54.254104.239.54.255254
56104.239.55.0/24104.239.55.1 to 104.239.55.254104.239.55.255254
57104.239.56.0/24104.239.56.1 to 104.239.56.254104.239.56.255254
58104.239.57.0/24104.239.57.1 to 104.239.57.254104.239.57.255254
59104.239.58.0/24104.239.58.1 to 104.239.58.254104.239.58.255254
60104.239.59.0/24104.239.59.1 to 104.239.59.254104.239.59.255254
61104.239.60.0/24104.239.60.1 to 104.239.60.254104.239.60.255254
62104.239.61.0/24104.239.61.1 to 104.239.61.254104.239.61.255254
63104.239.62.0/24104.239.62.1 to 104.239.62.254104.239.62.255254
64104.239.63.0/24104.239.63.1 to 104.239.63.254104.239.63.255254
65104.239.64.0/24104.239.64.1 to 104.239.64.254104.239.64.255254
66104.239.65.0/24104.239.65.1 to 104.239.65.254104.239.65.255254
67104.239.66.0/24104.239.66.1 to 104.239.66.254104.239.66.255254
68104.239.67.0/24104.239.67.1 to 104.239.67.254104.239.67.255254
69104.239.68.0/24104.239.68.1 to 104.239.68.254104.239.68.255254
70104.239.69.0/24104.239.69.1 to 104.239.69.254104.239.69.255254
71104.239.70.0/24104.239.70.1 to 104.239.70.254104.239.70.255254
72104.239.71.0/24104.239.71.1 to 104.239.71.254104.239.71.255254
73104.239.72.0/24104.239.72.1 to 104.239.72.254104.239.72.255254
74104.239.73.0/24104.239.73.1 to 104.239.73.254104.239.73.255254
75104.239.74.0/24104.239.74.1 to 104.239.74.254104.239.74.255254
76104.239.75.0/24104.239.75.1 to 104.239.75.254104.239.75.255254
77104.239.76.0/24104.239.76.1 to 104.239.76.254104.239.76.255254
78104.239.77.0/24104.239.77.1 to 104.239.77.254104.239.77.255254
79104.239.78.0/24104.239.78.1 to 104.239.78.254104.239.78.255254
80104.239.79.0/24104.239.79.1 to 104.239.79.254104.239.79.255254
81104.239.80.0/24104.239.80.1 to 104.239.80.254104.239.80.255254
82104.239.81.0/24104.239.81.1 to 104.239.81.254104.239.81.255254
83104.239.82.0/24104.239.82.1 to 104.239.82.254104.239.82.255254
84104.239.83.0/24104.239.83.1 to 104.239.83.254104.239.83.255254
85104.239.84.0/24104.239.84.1 to 104.239.84.254104.239.84.255254
86104.239.85.0/24104.239.85.1 to 104.239.85.254104.239.85.255254
87104.239.86.0/24104.239.86.1 to 104.239.86.254104.239.86.255254
88104.239.87.0/24104.239.87.1 to 104.239.87.254104.239.87.255254
89104.239.88.0/24104.239.88.1 to 104.239.88.254104.239.88.255254
90104.239.89.0/24104.239.89.1 to 104.239.89.254104.239.89.255254
91104.239.90.0/24104.239.90.1 to 104.239.90.254104.239.90.255254
92104.239.91.0/24104.239.91.1 to 104.239.91.254104.239.91.255254
93104.239.92.0/24104.239.92.1 to 104.239.92.254104.239.92.255254
94104.239.93.0/24104.239.93.1 to 104.239.93.254104.239.93.255254
95104.239.94.0/24104.239.94.1 to 104.239.94.254104.239.94.255254
96104.239.95.0/24104.239.95.1 to 104.239.95.254104.239.95.255254
97104.239.96.0/24104.239.96.1 to 104.239.96.254104.239.96.255254
98104.239.97.0/24104.239.97.1 to 104.239.97.254104.239.97.255254
99104.239.98.0/24104.239.98.1 to 104.239.98.254104.239.98.255254
100104.239.99.0/24104.239.99.1 to 104.239.99.254104.239.99.255254
101104.239.100.0/24104.239.100.1 to 104.239.100.254104.239.100.255254
102104.239.101.0/24104.239.101.1 to 104.239.101.254104.239.101.255254
103104.239.102.0/24104.239.102.1 to 104.239.102.254104.239.102.255254
104104.239.103.0/24104.239.103.1 to 104.239.103.254104.239.103.255254
105104.239.104.0/24104.239.104.1 to 104.239.104.254104.239.104.255254
106104.239.105.0/24104.239.105.1 to 104.239.105.254104.239.105.255254
107104.239.106.0/24104.239.106.1 to 104.239.106.254104.239.106.255254
108104.239.107.0/24104.239.107.1 to 104.239.107.254104.239.107.255254
109104.239.108.0/24104.239.108.1 to 104.239.108.254104.239.108.255254
110104.239.109.0/24104.239.109.1 to 104.239.109.254104.239.109.255254
111104.239.110.0/24104.239.110.1 to 104.239.110.254104.239.110.255254
112104.239.111.0/24104.239.111.1 to 104.239.111.254104.239.111.255254
113104.239.112.0/24104.239.112.1 to 104.239.112.254104.239.112.255254
114104.239.113.0/24104.239.113.1 to 104.239.113.254104.239.113.255254
115104.239.114.0/24104.239.114.1 to 104.239.114.254104.239.114.255254
116104.239.115.0/24104.239.115.1 to 104.239.115.254104.239.115.255254
117104.239.116.0/24104.239.116.1 to 104.239.116.254104.239.116.255254
118104.239.117.0/24104.239.117.1 to 104.239.117.254104.239.117.255254
119104.239.118.0/24104.239.118.1 to 104.239.118.254104.239.118.255254
120104.239.119.0/24104.239.119.1 to 104.239.119.254104.239.119.255254
121104.239.120.0/24104.239.120.1 to 104.239.120.254104.239.120.255254
122104.239.121.0/24104.239.121.1 to 104.239.121.254104.239.121.255254
123104.239.122.0/24104.239.122.1 to 104.239.122.254104.239.122.255254
124104.239.123.0/24104.239.123.1 to 104.239.123.254104.239.123.255254
125104.239.124.0/24104.239.124.1 to 104.239.124.254104.239.124.255254
126104.239.125.0/24104.239.125.1 to 104.239.125.254104.239.125.255254
127104.239.126.0/24104.239.126.1 to 104.239.126.254104.239.126.255254
128104.239.127.0/24104.239.127.1 to 104.239.127.254104.239.127.255254
129104.239.128.0/24104.239.128.1 to 104.239.128.254104.239.128.255254
130104.239.129.0/24104.239.129.1 to 104.239.129.254104.239.129.255254
131104.239.130.0/24104.239.130.1 to 104.239.130.254104.239.130.255254
132104.239.131.0/24104.239.131.1 to 104.239.131.254104.239.131.255254
133104.239.132.0/24104.239.132.1 to 104.239.132.254104.239.132.255254
134104.239.133.0/24104.239.133.1 to 104.239.133.254104.239.133.255254
135104.239.134.0/24104.239.134.1 to 104.239.134.254104.239.134.255254
136104.239.135.0/24104.239.135.1 to 104.239.135.254104.239.135.255254
137104.239.136.0/24104.239.136.1 to 104.239.136.254104.239.136.255254
138104.239.137.0/24104.239.137.1 to 104.239.137.254104.239.137.255254
139104.239.138.0/24104.239.138.1 to 104.239.138.254104.239.138.255254
140104.239.139.0/24104.239.139.1 to 104.239.139.254104.239.139.255254
141104.239.140.0/24104.239.140.1 to 104.239.140.254104.239.140.255254
142104.239.141.0/24104.239.141.1 to 104.239.141.254104.239.141.255254
143104.239.142.0/24104.239.142.1 to 104.239.142.254104.239.142.255254
144104.239.143.0/24104.239.143.1 to 104.239.143.254104.239.143.255254
145104.239.144.0/24104.239.144.1 to 104.239.144.254104.239.144.255254
146104.239.145.0/24104.239.145.1 to 104.239.145.254104.239.145.255254
147104.239.146.0/24104.239.146.1 to 104.239.146.254104.239.146.255254
148104.239.147.0/24104.239.147.1 to 104.239.147.254104.239.147.255254
149104.239.148.0/24104.239.148.1 to 104.239.148.254104.239.148.255254
150104.239.149.0/24104.239.149.1 to 104.239.149.254104.239.149.255254
151104.239.150.0/24104.239.150.1 to 104.239.150.254104.239.150.255254
152104.239.151.0/24104.239.151.1 to 104.239.151.254104.239.151.255254
153104.239.152.0/24104.239.152.1 to 104.239.152.254104.239.152.255254
154104.239.153.0/24104.239.153.1 to 104.239.153.254104.239.153.255254
155104.239.154.0/24104.239.154.1 to 104.239.154.254104.239.154.255254
156104.239.155.0/24104.239.155.1 to 104.239.155.254104.239.155.255254
157104.239.156.0/24104.239.156.1 to 104.239.156.254104.239.156.255254
158104.239.157.0/24104.239.157.1 to 104.239.157.254104.239.157.255254
159104.239.158.0/24104.239.158.1 to 104.239.158.254104.239.158.255254
160104.239.159.0/24104.239.159.1 to 104.239.159.254104.239.159.255254
161104.239.160.0/24104.239.160.1 to 104.239.160.254104.239.160.255254
162104.239.161.0/24104.239.161.1 to 104.239.161.254104.239.161.255254
163104.239.162.0/24104.239.162.1 to 104.239.162.254104.239.162.255254
164104.239.163.0/24104.239.163.1 to 104.239.163.254104.239.163.255254
165104.239.164.0/24104.239.164.1 to 104.239.164.254104.239.164.255254
166104.239.165.0/24104.239.165.1 to 104.239.165.254104.239.165.255254
167104.239.166.0/24104.239.166.1 to 104.239.166.254104.239.166.255254
168104.239.167.0/24104.239.167.1 to 104.239.167.254104.239.167.255254
169104.239.168.0/24104.239.168.1 to 104.239.168.254104.239.168.255254
170104.239.169.0/24104.239.169.1 to 104.239.169.254104.239.169.255254
171104.239.170.0/24104.239.170.1 to 104.239.170.254104.239.170.255254
172104.239.171.0/24104.239.171.1 to 104.239.171.254104.239.171.255254
173104.239.172.0/24104.239.172.1 to 104.239.172.254104.239.172.255254
174104.239.173.0/24104.239.173.1 to 104.239.173.254104.239.173.255254
175104.239.174.0/24104.239.174.1 to 104.239.174.254104.239.174.255254
176104.239.175.0/24104.239.175.1 to 104.239.175.254104.239.175.255254
177104.239.176.0/24104.239.176.1 to 104.239.176.254104.239.176.255254
178104.239.177.0/24104.239.177.1 to 104.239.177.254104.239.177.255254
179104.239.178.0/24104.239.178.1 to 104.239.178.254104.239.178.255254
180104.239.179.0/24104.239.179.1 to 104.239.179.254104.239.179.255254
181104.239.180.0/24104.239.180.1 to 104.239.180.254104.239.180.255254
182104.239.181.0/24104.239.181.1 to 104.239.181.254104.239.181.255254
183104.239.182.0/24104.239.182.1 to 104.239.182.254104.239.182.255254
184104.239.183.0/24104.239.183.1 to 104.239.183.254104.239.183.255254
185104.239.184.0/24104.239.184.1 to 104.239.184.254104.239.184.255254
186104.239.185.0/24104.239.185.1 to 104.239.185.254104.239.185.255254
187104.239.186.0/24104.239.186.1 to 104.239.186.254104.239.186.255254
188104.239.187.0/24104.239.187.1 to 104.239.187.254104.239.187.255254
189104.239.188.0/24104.239.188.1 to 104.239.188.254104.239.188.255254
190104.239.189.0/24104.239.189.1 to 104.239.189.254104.239.189.255254
191104.239.190.0/24104.239.190.1 to 104.239.190.254104.239.190.255254
192104.239.191.0/24104.239.191.1 to 104.239.191.254104.239.191.255254
193104.239.192.0/24104.239.192.1 to 104.239.192.254104.239.192.255254
194104.239.193.0/24104.239.193.1 to 104.239.193.254104.239.193.255254
195104.239.194.0/24104.239.194.1 to 104.239.194.254104.239.194.255254
196104.239.195.0/24104.239.195.1 to 104.239.195.254104.239.195.255254
197104.239.196.0/24104.239.196.1 to 104.239.196.254104.239.196.255254
198104.239.197.0/24104.239.197.1 to 104.239.197.254104.239.197.255254
199104.239.198.0/24104.239.198.1 to 104.239.198.254104.239.198.255254
200104.239.199.0/24104.239.199.1 to 104.239.199.254104.239.199.255254
201104.239.200.0/24104.239.200.1 to 104.239.200.254104.239.200.255254
202104.239.201.0/24104.239.201.1 to 104.239.201.254104.239.201.255254
203104.239.202.0/24104.239.202.1 to 104.239.202.254104.239.202.255254
204104.239.203.0/24104.239.203.1 to 104.239.203.254104.239.203.255254
205104.239.204.0/24104.239.204.1 to 104.239.204.254104.239.204.255254
206104.239.205.0/24104.239.205.1 to 104.239.205.254104.239.205.255254
207104.239.206.0/24104.239.206.1 to 104.239.206.254104.239.206.255254
208104.239.207.0/24104.239.207.1 to 104.239.207.254104.239.207.255254
209104.239.208.0/24104.239.208.1 to 104.239.208.254104.239.208.255254
210104.239.209.0/24104.239.209.1 to 104.239.209.254104.239.209.255254
211104.239.210.0/24104.239.210.1 to 104.239.210.254104.239.210.255254
212104.239.211.0/24104.239.211.1 to 104.239.211.254104.239.211.255254
213104.239.212.0/24104.239.212.1 to 104.239.212.254104.239.212.255254
214104.239.213.0/24104.239.213.1 to 104.239.213.254104.239.213.255254
215104.239.214.0/24104.239.214.1 to 104.239.214.254104.239.214.255254
216104.239.215.0/24104.239.215.1 to 104.239.215.254104.239.215.255254
217104.239.216.0/24104.239.216.1 to 104.239.216.254104.239.216.255254
218104.239.217.0/24104.239.217.1 to 104.239.217.254104.239.217.255254
219104.239.218.0/24104.239.218.1 to 104.239.218.254104.239.218.255254
220104.239.219.0/24104.239.219.1 to 104.239.219.254104.239.219.255254
221104.239.220.0/24104.239.220.1 to 104.239.220.254104.239.220.255254
222104.239.221.0/24104.239.221.1 to 104.239.221.254104.239.221.255254
223104.239.222.0/24104.239.222.1 to 104.239.222.254104.239.222.255254
224104.239.223.0/24104.239.223.1 to 104.239.223.254104.239.223.255254
225104.239.224.0/24104.239.224.1 to 104.239.224.254104.239.224.255254
226104.239.225.0/24104.239.225.1 to 104.239.225.254104.239.225.255254
227104.239.226.0/24104.239.226.1 to 104.239.226.254104.239.226.255254
228104.239.227.0/24104.239.227.1 to 104.239.227.254104.239.227.255254
229104.239.228.0/24104.239.228.1 to 104.239.228.254104.239.228.255254
230104.239.229.0/24104.239.229.1 to 104.239.229.254104.239.229.255254
231104.239.230.0/24104.239.230.1 to 104.239.230.254104.239.230.255254
232104.239.231.0/24104.239.231.1 to 104.239.231.254104.239.231.255254
233104.239.232.0/24104.239.232.1 to 104.239.232.254104.239.232.255254
234104.239.233.0/24104.239.233.1 to 104.239.233.254104.239.233.255254
235104.239.234.0/24104.239.234.1 to 104.239.234.254104.239.234.255254
236104.239.235.0/24104.239.235.1 to 104.239.235.254104.239.235.255254
237104.239.236.0/24104.239.236.1 to 104.239.236.254104.239.236.255254
238104.239.237.0/24104.239.237.1 to 104.239.237.254104.239.237.255254
239104.239.238.0/24104.239.238.1 to 104.239.238.254104.239.238.255254
240104.239.239.0/24104.239.239.1 to 104.239.239.254104.239.239.255254
241104.239.240.0/24104.239.240.1 to 104.239.240.254104.239.240.255254
242104.239.241.0/24104.239.241.1 to 104.239.241.254104.239.241.255254
243104.239.242.0/24104.239.242.1 to 104.239.242.254104.239.242.255254
244104.239.243.0/24104.239.243.1 to 104.239.243.254104.239.243.255254
245104.239.244.0/24104.239.244.1 to 104.239.244.254104.239.244.255254
246104.239.245.0/24104.239.245.1 to 104.239.245.254104.239.245.255254
247104.239.246.0/24104.239.246.1 to 104.239.246.254104.239.246.255254
248104.239.247.0/24104.239.247.1 to 104.239.247.254104.239.247.255254
249104.239.248.0/24104.239.248.1 to 104.239.248.254104.239.248.255254
250104.239.249.0/24104.239.249.1 to 104.239.249.254104.239.249.255254
251104.239.250.0/24104.239.250.1 to 104.239.250.254104.239.250.255254
252104.239.251.0/24104.239.251.1 to 104.239.251.254104.239.251.255254
253104.239.252.0/24104.239.252.1 to 104.239.252.254104.239.252.255254
254104.239.253.0/24104.239.253.1 to 104.239.253.254104.239.253.255254
255104.239.254.0/24104.239.254.1 to 104.239.254.254104.239.254.255254
256104.239.255.0/24104.239.255.1 to 104.239.255.254104.239.255.255254

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.