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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.

Network102.64.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
102.64.0.0
Broadcast address
102.79.255.255
First usable
102.64.0.1
Last usable
102.79.255.254
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
Public public
Old class
A (default /8)
As numbers
Hex 66400000 · Integer 1715470336 to 1716518911
Reverse DNS zones
64.102.in-addr.arpa
65.102.in-addr.arpa
66.102.in-addr.arpa
67.102.in-addr.arpa
68.102.in-addr.arpa
69.102.in-addr.arpa
70.102.in-addr.arpa
71.102.in-addr.arpa
72.102.in-addr.arpa
73.102.in-addr.arpa
74.102.in-addr.arpa
75.102.in-addr.arpa
76.102.in-addr.arpa
77.102.in-addr.arpa
78.102.in-addr.arpa
79.102.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
Address01100110.01000000.00000000.00000000102.64.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network01100110.01000000.00000000.00000000102.64.0.0
Broadcast01100110.01001111.11111111.11111111102.79.255.255
Split into smaller subnets/23
/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)

102.64.0.0/12 makes 2,048 subnets of /23; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1102.64.0.0/23102.64.0.1 to 102.64.1.254102.64.1.255510
2102.64.2.0/23102.64.2.1 to 102.64.3.254102.64.3.255510
3102.64.4.0/23102.64.4.1 to 102.64.5.254102.64.5.255510
4102.64.6.0/23102.64.6.1 to 102.64.7.254102.64.7.255510
5102.64.8.0/23102.64.8.1 to 102.64.9.254102.64.9.255510
6102.64.10.0/23102.64.10.1 to 102.64.11.254102.64.11.255510
7102.64.12.0/23102.64.12.1 to 102.64.13.254102.64.13.255510
8102.64.14.0/23102.64.14.1 to 102.64.15.254102.64.15.255510
9102.64.16.0/23102.64.16.1 to 102.64.17.254102.64.17.255510
10102.64.18.0/23102.64.18.1 to 102.64.19.254102.64.19.255510
11102.64.20.0/23102.64.20.1 to 102.64.21.254102.64.21.255510
12102.64.22.0/23102.64.22.1 to 102.64.23.254102.64.23.255510
13102.64.24.0/23102.64.24.1 to 102.64.25.254102.64.25.255510
14102.64.26.0/23102.64.26.1 to 102.64.27.254102.64.27.255510
15102.64.28.0/23102.64.28.1 to 102.64.29.254102.64.29.255510
16102.64.30.0/23102.64.30.1 to 102.64.31.254102.64.31.255510
17102.64.32.0/23102.64.32.1 to 102.64.33.254102.64.33.255510
18102.64.34.0/23102.64.34.1 to 102.64.35.254102.64.35.255510
19102.64.36.0/23102.64.36.1 to 102.64.37.254102.64.37.255510
20102.64.38.0/23102.64.38.1 to 102.64.39.254102.64.39.255510
21102.64.40.0/23102.64.40.1 to 102.64.41.254102.64.41.255510
22102.64.42.0/23102.64.42.1 to 102.64.43.254102.64.43.255510
23102.64.44.0/23102.64.44.1 to 102.64.45.254102.64.45.255510
24102.64.46.0/23102.64.46.1 to 102.64.47.254102.64.47.255510
25102.64.48.0/23102.64.48.1 to 102.64.49.254102.64.49.255510
26102.64.50.0/23102.64.50.1 to 102.64.51.254102.64.51.255510
27102.64.52.0/23102.64.52.1 to 102.64.53.254102.64.53.255510
28102.64.54.0/23102.64.54.1 to 102.64.55.254102.64.55.255510
29102.64.56.0/23102.64.56.1 to 102.64.57.254102.64.57.255510
30102.64.58.0/23102.64.58.1 to 102.64.59.254102.64.59.255510
31102.64.60.0/23102.64.60.1 to 102.64.61.254102.64.61.255510
32102.64.62.0/23102.64.62.1 to 102.64.63.254102.64.63.255510
33102.64.64.0/23102.64.64.1 to 102.64.65.254102.64.65.255510
34102.64.66.0/23102.64.66.1 to 102.64.67.254102.64.67.255510
35102.64.68.0/23102.64.68.1 to 102.64.69.254102.64.69.255510
36102.64.70.0/23102.64.70.1 to 102.64.71.254102.64.71.255510
37102.64.72.0/23102.64.72.1 to 102.64.73.254102.64.73.255510
38102.64.74.0/23102.64.74.1 to 102.64.75.254102.64.75.255510
39102.64.76.0/23102.64.76.1 to 102.64.77.254102.64.77.255510
40102.64.78.0/23102.64.78.1 to 102.64.79.254102.64.79.255510
41102.64.80.0/23102.64.80.1 to 102.64.81.254102.64.81.255510
42102.64.82.0/23102.64.82.1 to 102.64.83.254102.64.83.255510
43102.64.84.0/23102.64.84.1 to 102.64.85.254102.64.85.255510
44102.64.86.0/23102.64.86.1 to 102.64.87.254102.64.87.255510
45102.64.88.0/23102.64.88.1 to 102.64.89.254102.64.89.255510
46102.64.90.0/23102.64.90.1 to 102.64.91.254102.64.91.255510
47102.64.92.0/23102.64.92.1 to 102.64.93.254102.64.93.255510
48102.64.94.0/23102.64.94.1 to 102.64.95.254102.64.95.255510
49102.64.96.0/23102.64.96.1 to 102.64.97.254102.64.97.255510
50102.64.98.0/23102.64.98.1 to 102.64.99.254102.64.99.255510
51102.64.100.0/23102.64.100.1 to 102.64.101.254102.64.101.255510
52102.64.102.0/23102.64.102.1 to 102.64.103.254102.64.103.255510
53102.64.104.0/23102.64.104.1 to 102.64.105.254102.64.105.255510
54102.64.106.0/23102.64.106.1 to 102.64.107.254102.64.107.255510
55102.64.108.0/23102.64.108.1 to 102.64.109.254102.64.109.255510
56102.64.110.0/23102.64.110.1 to 102.64.111.254102.64.111.255510
57102.64.112.0/23102.64.112.1 to 102.64.113.254102.64.113.255510
58102.64.114.0/23102.64.114.1 to 102.64.115.254102.64.115.255510
59102.64.116.0/23102.64.116.1 to 102.64.117.254102.64.117.255510
60102.64.118.0/23102.64.118.1 to 102.64.119.254102.64.119.255510
61102.64.120.0/23102.64.120.1 to 102.64.121.254102.64.121.255510
62102.64.122.0/23102.64.122.1 to 102.64.123.254102.64.123.255510
63102.64.124.0/23102.64.124.1 to 102.64.125.254102.64.125.255510
64102.64.126.0/23102.64.126.1 to 102.64.127.254102.64.127.255510
65102.64.128.0/23102.64.128.1 to 102.64.129.254102.64.129.255510
66102.64.130.0/23102.64.130.1 to 102.64.131.254102.64.131.255510
67102.64.132.0/23102.64.132.1 to 102.64.133.254102.64.133.255510
68102.64.134.0/23102.64.134.1 to 102.64.135.254102.64.135.255510
69102.64.136.0/23102.64.136.1 to 102.64.137.254102.64.137.255510
70102.64.138.0/23102.64.138.1 to 102.64.139.254102.64.139.255510
71102.64.140.0/23102.64.140.1 to 102.64.141.254102.64.141.255510
72102.64.142.0/23102.64.142.1 to 102.64.143.254102.64.143.255510
73102.64.144.0/23102.64.144.1 to 102.64.145.254102.64.145.255510
74102.64.146.0/23102.64.146.1 to 102.64.147.254102.64.147.255510
75102.64.148.0/23102.64.148.1 to 102.64.149.254102.64.149.255510
76102.64.150.0/23102.64.150.1 to 102.64.151.254102.64.151.255510
77102.64.152.0/23102.64.152.1 to 102.64.153.254102.64.153.255510
78102.64.154.0/23102.64.154.1 to 102.64.155.254102.64.155.255510
79102.64.156.0/23102.64.156.1 to 102.64.157.254102.64.157.255510
80102.64.158.0/23102.64.158.1 to 102.64.159.254102.64.159.255510
81102.64.160.0/23102.64.160.1 to 102.64.161.254102.64.161.255510
82102.64.162.0/23102.64.162.1 to 102.64.163.254102.64.163.255510
83102.64.164.0/23102.64.164.1 to 102.64.165.254102.64.165.255510
84102.64.166.0/23102.64.166.1 to 102.64.167.254102.64.167.255510
85102.64.168.0/23102.64.168.1 to 102.64.169.254102.64.169.255510
86102.64.170.0/23102.64.170.1 to 102.64.171.254102.64.171.255510
87102.64.172.0/23102.64.172.1 to 102.64.173.254102.64.173.255510
88102.64.174.0/23102.64.174.1 to 102.64.175.254102.64.175.255510
89102.64.176.0/23102.64.176.1 to 102.64.177.254102.64.177.255510
90102.64.178.0/23102.64.178.1 to 102.64.179.254102.64.179.255510
91102.64.180.0/23102.64.180.1 to 102.64.181.254102.64.181.255510
92102.64.182.0/23102.64.182.1 to 102.64.183.254102.64.183.255510
93102.64.184.0/23102.64.184.1 to 102.64.185.254102.64.185.255510
94102.64.186.0/23102.64.186.1 to 102.64.187.254102.64.187.255510
95102.64.188.0/23102.64.188.1 to 102.64.189.254102.64.189.255510
96102.64.190.0/23102.64.190.1 to 102.64.191.254102.64.191.255510
97102.64.192.0/23102.64.192.1 to 102.64.193.254102.64.193.255510
98102.64.194.0/23102.64.194.1 to 102.64.195.254102.64.195.255510
99102.64.196.0/23102.64.196.1 to 102.64.197.254102.64.197.255510
100102.64.198.0/23102.64.198.1 to 102.64.199.254102.64.199.255510
101102.64.200.0/23102.64.200.1 to 102.64.201.254102.64.201.255510
102102.64.202.0/23102.64.202.1 to 102.64.203.254102.64.203.255510
103102.64.204.0/23102.64.204.1 to 102.64.205.254102.64.205.255510
104102.64.206.0/23102.64.206.1 to 102.64.207.254102.64.207.255510
105102.64.208.0/23102.64.208.1 to 102.64.209.254102.64.209.255510
106102.64.210.0/23102.64.210.1 to 102.64.211.254102.64.211.255510
107102.64.212.0/23102.64.212.1 to 102.64.213.254102.64.213.255510
108102.64.214.0/23102.64.214.1 to 102.64.215.254102.64.215.255510
109102.64.216.0/23102.64.216.1 to 102.64.217.254102.64.217.255510
110102.64.218.0/23102.64.218.1 to 102.64.219.254102.64.219.255510
111102.64.220.0/23102.64.220.1 to 102.64.221.254102.64.221.255510
112102.64.222.0/23102.64.222.1 to 102.64.223.254102.64.223.255510
113102.64.224.0/23102.64.224.1 to 102.64.225.254102.64.225.255510
114102.64.226.0/23102.64.226.1 to 102.64.227.254102.64.227.255510
115102.64.228.0/23102.64.228.1 to 102.64.229.254102.64.229.255510
116102.64.230.0/23102.64.230.1 to 102.64.231.254102.64.231.255510
117102.64.232.0/23102.64.232.1 to 102.64.233.254102.64.233.255510
118102.64.234.0/23102.64.234.1 to 102.64.235.254102.64.235.255510
119102.64.236.0/23102.64.236.1 to 102.64.237.254102.64.237.255510
120102.64.238.0/23102.64.238.1 to 102.64.239.254102.64.239.255510
121102.64.240.0/23102.64.240.1 to 102.64.241.254102.64.241.255510
122102.64.242.0/23102.64.242.1 to 102.64.243.254102.64.243.255510
123102.64.244.0/23102.64.244.1 to 102.64.245.254102.64.245.255510
124102.64.246.0/23102.64.246.1 to 102.64.247.254102.64.247.255510
125102.64.248.0/23102.64.248.1 to 102.64.249.254102.64.249.255510
126102.64.250.0/23102.64.250.1 to 102.64.251.254102.64.251.255510
127102.64.252.0/23102.64.252.1 to 102.64.253.254102.64.253.255510
128102.64.254.0/23102.64.254.1 to 102.64.255.254102.64.255.255510
129102.65.0.0/23102.65.0.1 to 102.65.1.254102.65.1.255510
130102.65.2.0/23102.65.2.1 to 102.65.3.254102.65.3.255510
131102.65.4.0/23102.65.4.1 to 102.65.5.254102.65.5.255510
132102.65.6.0/23102.65.6.1 to 102.65.7.254102.65.7.255510
133102.65.8.0/23102.65.8.1 to 102.65.9.254102.65.9.255510
134102.65.10.0/23102.65.10.1 to 102.65.11.254102.65.11.255510
135102.65.12.0/23102.65.12.1 to 102.65.13.254102.65.13.255510
136102.65.14.0/23102.65.14.1 to 102.65.15.254102.65.15.255510
137102.65.16.0/23102.65.16.1 to 102.65.17.254102.65.17.255510
138102.65.18.0/23102.65.18.1 to 102.65.19.254102.65.19.255510
139102.65.20.0/23102.65.20.1 to 102.65.21.254102.65.21.255510
140102.65.22.0/23102.65.22.1 to 102.65.23.254102.65.23.255510
141102.65.24.0/23102.65.24.1 to 102.65.25.254102.65.25.255510
142102.65.26.0/23102.65.26.1 to 102.65.27.254102.65.27.255510
143102.65.28.0/23102.65.28.1 to 102.65.29.254102.65.29.255510
144102.65.30.0/23102.65.30.1 to 102.65.31.254102.65.31.255510
145102.65.32.0/23102.65.32.1 to 102.65.33.254102.65.33.255510
146102.65.34.0/23102.65.34.1 to 102.65.35.254102.65.35.255510
147102.65.36.0/23102.65.36.1 to 102.65.37.254102.65.37.255510
148102.65.38.0/23102.65.38.1 to 102.65.39.254102.65.39.255510
149102.65.40.0/23102.65.40.1 to 102.65.41.254102.65.41.255510
150102.65.42.0/23102.65.42.1 to 102.65.43.254102.65.43.255510
151102.65.44.0/23102.65.44.1 to 102.65.45.254102.65.45.255510
152102.65.46.0/23102.65.46.1 to 102.65.47.254102.65.47.255510
153102.65.48.0/23102.65.48.1 to 102.65.49.254102.65.49.255510
154102.65.50.0/23102.65.50.1 to 102.65.51.254102.65.51.255510
155102.65.52.0/23102.65.52.1 to 102.65.53.254102.65.53.255510
156102.65.54.0/23102.65.54.1 to 102.65.55.254102.65.55.255510
157102.65.56.0/23102.65.56.1 to 102.65.57.254102.65.57.255510
158102.65.58.0/23102.65.58.1 to 102.65.59.254102.65.59.255510
159102.65.60.0/23102.65.60.1 to 102.65.61.254102.65.61.255510
160102.65.62.0/23102.65.62.1 to 102.65.63.254102.65.63.255510
161102.65.64.0/23102.65.64.1 to 102.65.65.254102.65.65.255510
162102.65.66.0/23102.65.66.1 to 102.65.67.254102.65.67.255510
163102.65.68.0/23102.65.68.1 to 102.65.69.254102.65.69.255510
164102.65.70.0/23102.65.70.1 to 102.65.71.254102.65.71.255510
165102.65.72.0/23102.65.72.1 to 102.65.73.254102.65.73.255510
166102.65.74.0/23102.65.74.1 to 102.65.75.254102.65.75.255510
167102.65.76.0/23102.65.76.1 to 102.65.77.254102.65.77.255510
168102.65.78.0/23102.65.78.1 to 102.65.79.254102.65.79.255510
169102.65.80.0/23102.65.80.1 to 102.65.81.254102.65.81.255510
170102.65.82.0/23102.65.82.1 to 102.65.83.254102.65.83.255510
171102.65.84.0/23102.65.84.1 to 102.65.85.254102.65.85.255510
172102.65.86.0/23102.65.86.1 to 102.65.87.254102.65.87.255510
173102.65.88.0/23102.65.88.1 to 102.65.89.254102.65.89.255510
174102.65.90.0/23102.65.90.1 to 102.65.91.254102.65.91.255510
175102.65.92.0/23102.65.92.1 to 102.65.93.254102.65.93.255510
176102.65.94.0/23102.65.94.1 to 102.65.95.254102.65.95.255510
177102.65.96.0/23102.65.96.1 to 102.65.97.254102.65.97.255510
178102.65.98.0/23102.65.98.1 to 102.65.99.254102.65.99.255510
179102.65.100.0/23102.65.100.1 to 102.65.101.254102.65.101.255510
180102.65.102.0/23102.65.102.1 to 102.65.103.254102.65.103.255510
181102.65.104.0/23102.65.104.1 to 102.65.105.254102.65.105.255510
182102.65.106.0/23102.65.106.1 to 102.65.107.254102.65.107.255510
183102.65.108.0/23102.65.108.1 to 102.65.109.254102.65.109.255510
184102.65.110.0/23102.65.110.1 to 102.65.111.254102.65.111.255510
185102.65.112.0/23102.65.112.1 to 102.65.113.254102.65.113.255510
186102.65.114.0/23102.65.114.1 to 102.65.115.254102.65.115.255510
187102.65.116.0/23102.65.116.1 to 102.65.117.254102.65.117.255510
188102.65.118.0/23102.65.118.1 to 102.65.119.254102.65.119.255510
189102.65.120.0/23102.65.120.1 to 102.65.121.254102.65.121.255510
190102.65.122.0/23102.65.122.1 to 102.65.123.254102.65.123.255510
191102.65.124.0/23102.65.124.1 to 102.65.125.254102.65.125.255510
192102.65.126.0/23102.65.126.1 to 102.65.127.254102.65.127.255510
193102.65.128.0/23102.65.128.1 to 102.65.129.254102.65.129.255510
194102.65.130.0/23102.65.130.1 to 102.65.131.254102.65.131.255510
195102.65.132.0/23102.65.132.1 to 102.65.133.254102.65.133.255510
196102.65.134.0/23102.65.134.1 to 102.65.135.254102.65.135.255510
197102.65.136.0/23102.65.136.1 to 102.65.137.254102.65.137.255510
198102.65.138.0/23102.65.138.1 to 102.65.139.254102.65.139.255510
199102.65.140.0/23102.65.140.1 to 102.65.141.254102.65.141.255510
200102.65.142.0/23102.65.142.1 to 102.65.143.254102.65.143.255510
201102.65.144.0/23102.65.144.1 to 102.65.145.254102.65.145.255510
202102.65.146.0/23102.65.146.1 to 102.65.147.254102.65.147.255510
203102.65.148.0/23102.65.148.1 to 102.65.149.254102.65.149.255510
204102.65.150.0/23102.65.150.1 to 102.65.151.254102.65.151.255510
205102.65.152.0/23102.65.152.1 to 102.65.153.254102.65.153.255510
206102.65.154.0/23102.65.154.1 to 102.65.155.254102.65.155.255510
207102.65.156.0/23102.65.156.1 to 102.65.157.254102.65.157.255510
208102.65.158.0/23102.65.158.1 to 102.65.159.254102.65.159.255510
209102.65.160.0/23102.65.160.1 to 102.65.161.254102.65.161.255510
210102.65.162.0/23102.65.162.1 to 102.65.163.254102.65.163.255510
211102.65.164.0/23102.65.164.1 to 102.65.165.254102.65.165.255510
212102.65.166.0/23102.65.166.1 to 102.65.167.254102.65.167.255510
213102.65.168.0/23102.65.168.1 to 102.65.169.254102.65.169.255510
214102.65.170.0/23102.65.170.1 to 102.65.171.254102.65.171.255510
215102.65.172.0/23102.65.172.1 to 102.65.173.254102.65.173.255510
216102.65.174.0/23102.65.174.1 to 102.65.175.254102.65.175.255510
217102.65.176.0/23102.65.176.1 to 102.65.177.254102.65.177.255510
218102.65.178.0/23102.65.178.1 to 102.65.179.254102.65.179.255510
219102.65.180.0/23102.65.180.1 to 102.65.181.254102.65.181.255510
220102.65.182.0/23102.65.182.1 to 102.65.183.254102.65.183.255510
221102.65.184.0/23102.65.184.1 to 102.65.185.254102.65.185.255510
222102.65.186.0/23102.65.186.1 to 102.65.187.254102.65.187.255510
223102.65.188.0/23102.65.188.1 to 102.65.189.254102.65.189.255510
224102.65.190.0/23102.65.190.1 to 102.65.191.254102.65.191.255510
225102.65.192.0/23102.65.192.1 to 102.65.193.254102.65.193.255510
226102.65.194.0/23102.65.194.1 to 102.65.195.254102.65.195.255510
227102.65.196.0/23102.65.196.1 to 102.65.197.254102.65.197.255510
228102.65.198.0/23102.65.198.1 to 102.65.199.254102.65.199.255510
229102.65.200.0/23102.65.200.1 to 102.65.201.254102.65.201.255510
230102.65.202.0/23102.65.202.1 to 102.65.203.254102.65.203.255510
231102.65.204.0/23102.65.204.1 to 102.65.205.254102.65.205.255510
232102.65.206.0/23102.65.206.1 to 102.65.207.254102.65.207.255510
233102.65.208.0/23102.65.208.1 to 102.65.209.254102.65.209.255510
234102.65.210.0/23102.65.210.1 to 102.65.211.254102.65.211.255510
235102.65.212.0/23102.65.212.1 to 102.65.213.254102.65.213.255510
236102.65.214.0/23102.65.214.1 to 102.65.215.254102.65.215.255510
237102.65.216.0/23102.65.216.1 to 102.65.217.254102.65.217.255510
238102.65.218.0/23102.65.218.1 to 102.65.219.254102.65.219.255510
239102.65.220.0/23102.65.220.1 to 102.65.221.254102.65.221.255510
240102.65.222.0/23102.65.222.1 to 102.65.223.254102.65.223.255510
241102.65.224.0/23102.65.224.1 to 102.65.225.254102.65.225.255510
242102.65.226.0/23102.65.226.1 to 102.65.227.254102.65.227.255510
243102.65.228.0/23102.65.228.1 to 102.65.229.254102.65.229.255510
244102.65.230.0/23102.65.230.1 to 102.65.231.254102.65.231.255510
245102.65.232.0/23102.65.232.1 to 102.65.233.254102.65.233.255510
246102.65.234.0/23102.65.234.1 to 102.65.235.254102.65.235.255510
247102.65.236.0/23102.65.236.1 to 102.65.237.254102.65.237.255510
248102.65.238.0/23102.65.238.1 to 102.65.239.254102.65.239.255510
249102.65.240.0/23102.65.240.1 to 102.65.241.254102.65.241.255510
250102.65.242.0/23102.65.242.1 to 102.65.243.254102.65.243.255510
251102.65.244.0/23102.65.244.1 to 102.65.245.254102.65.245.255510
252102.65.246.0/23102.65.246.1 to 102.65.247.254102.65.247.255510
253102.65.248.0/23102.65.248.1 to 102.65.249.254102.65.249.255510
254102.65.250.0/23102.65.250.1 to 102.65.251.254102.65.251.255510
255102.65.252.0/23102.65.252.1 to 102.65.253.254102.65.253.255510
256102.65.254.0/23102.65.254.1 to 102.65.255.254102.65.255.255510

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.