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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.

Network239.10.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
239.10.0.0
Broadcast address
239.11.255.255
First usable
239.10.0.1
Last usable
239.11.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex EF0A0000 · Integer 4010409984 to 4010541055
Reverse DNS zones
10.239.in-addr.arpa
11.239.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11101111.00001010.00000000.00000000239.10.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network11101111.00001010.00000000.00000000239.10.0.0
Broadcast11101111.00001011.11111111.11111111239.11.255.255
Split into smaller subnets/23
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

239.10.0.0/15 makes 256 subnets of /23.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1239.10.0.0/23239.10.0.1 to 239.10.1.254239.10.1.255510
2239.10.2.0/23239.10.2.1 to 239.10.3.254239.10.3.255510
3239.10.4.0/23239.10.4.1 to 239.10.5.254239.10.5.255510
4239.10.6.0/23239.10.6.1 to 239.10.7.254239.10.7.255510
5239.10.8.0/23239.10.8.1 to 239.10.9.254239.10.9.255510
6239.10.10.0/23239.10.10.1 to 239.10.11.254239.10.11.255510
7239.10.12.0/23239.10.12.1 to 239.10.13.254239.10.13.255510
8239.10.14.0/23239.10.14.1 to 239.10.15.254239.10.15.255510
9239.10.16.0/23239.10.16.1 to 239.10.17.254239.10.17.255510
10239.10.18.0/23239.10.18.1 to 239.10.19.254239.10.19.255510
11239.10.20.0/23239.10.20.1 to 239.10.21.254239.10.21.255510
12239.10.22.0/23239.10.22.1 to 239.10.23.254239.10.23.255510
13239.10.24.0/23239.10.24.1 to 239.10.25.254239.10.25.255510
14239.10.26.0/23239.10.26.1 to 239.10.27.254239.10.27.255510
15239.10.28.0/23239.10.28.1 to 239.10.29.254239.10.29.255510
16239.10.30.0/23239.10.30.1 to 239.10.31.254239.10.31.255510
17239.10.32.0/23239.10.32.1 to 239.10.33.254239.10.33.255510
18239.10.34.0/23239.10.34.1 to 239.10.35.254239.10.35.255510
19239.10.36.0/23239.10.36.1 to 239.10.37.254239.10.37.255510
20239.10.38.0/23239.10.38.1 to 239.10.39.254239.10.39.255510
21239.10.40.0/23239.10.40.1 to 239.10.41.254239.10.41.255510
22239.10.42.0/23239.10.42.1 to 239.10.43.254239.10.43.255510
23239.10.44.0/23239.10.44.1 to 239.10.45.254239.10.45.255510
24239.10.46.0/23239.10.46.1 to 239.10.47.254239.10.47.255510
25239.10.48.0/23239.10.48.1 to 239.10.49.254239.10.49.255510
26239.10.50.0/23239.10.50.1 to 239.10.51.254239.10.51.255510
27239.10.52.0/23239.10.52.1 to 239.10.53.254239.10.53.255510
28239.10.54.0/23239.10.54.1 to 239.10.55.254239.10.55.255510
29239.10.56.0/23239.10.56.1 to 239.10.57.254239.10.57.255510
30239.10.58.0/23239.10.58.1 to 239.10.59.254239.10.59.255510
31239.10.60.0/23239.10.60.1 to 239.10.61.254239.10.61.255510
32239.10.62.0/23239.10.62.1 to 239.10.63.254239.10.63.255510
33239.10.64.0/23239.10.64.1 to 239.10.65.254239.10.65.255510
34239.10.66.0/23239.10.66.1 to 239.10.67.254239.10.67.255510
35239.10.68.0/23239.10.68.1 to 239.10.69.254239.10.69.255510
36239.10.70.0/23239.10.70.1 to 239.10.71.254239.10.71.255510
37239.10.72.0/23239.10.72.1 to 239.10.73.254239.10.73.255510
38239.10.74.0/23239.10.74.1 to 239.10.75.254239.10.75.255510
39239.10.76.0/23239.10.76.1 to 239.10.77.254239.10.77.255510
40239.10.78.0/23239.10.78.1 to 239.10.79.254239.10.79.255510
41239.10.80.0/23239.10.80.1 to 239.10.81.254239.10.81.255510
42239.10.82.0/23239.10.82.1 to 239.10.83.254239.10.83.255510
43239.10.84.0/23239.10.84.1 to 239.10.85.254239.10.85.255510
44239.10.86.0/23239.10.86.1 to 239.10.87.254239.10.87.255510
45239.10.88.0/23239.10.88.1 to 239.10.89.254239.10.89.255510
46239.10.90.0/23239.10.90.1 to 239.10.91.254239.10.91.255510
47239.10.92.0/23239.10.92.1 to 239.10.93.254239.10.93.255510
48239.10.94.0/23239.10.94.1 to 239.10.95.254239.10.95.255510
49239.10.96.0/23239.10.96.1 to 239.10.97.254239.10.97.255510
50239.10.98.0/23239.10.98.1 to 239.10.99.254239.10.99.255510
51239.10.100.0/23239.10.100.1 to 239.10.101.254239.10.101.255510
52239.10.102.0/23239.10.102.1 to 239.10.103.254239.10.103.255510
53239.10.104.0/23239.10.104.1 to 239.10.105.254239.10.105.255510
54239.10.106.0/23239.10.106.1 to 239.10.107.254239.10.107.255510
55239.10.108.0/23239.10.108.1 to 239.10.109.254239.10.109.255510
56239.10.110.0/23239.10.110.1 to 239.10.111.254239.10.111.255510
57239.10.112.0/23239.10.112.1 to 239.10.113.254239.10.113.255510
58239.10.114.0/23239.10.114.1 to 239.10.115.254239.10.115.255510
59239.10.116.0/23239.10.116.1 to 239.10.117.254239.10.117.255510
60239.10.118.0/23239.10.118.1 to 239.10.119.254239.10.119.255510
61239.10.120.0/23239.10.120.1 to 239.10.121.254239.10.121.255510
62239.10.122.0/23239.10.122.1 to 239.10.123.254239.10.123.255510
63239.10.124.0/23239.10.124.1 to 239.10.125.254239.10.125.255510
64239.10.126.0/23239.10.126.1 to 239.10.127.254239.10.127.255510
65239.10.128.0/23239.10.128.1 to 239.10.129.254239.10.129.255510
66239.10.130.0/23239.10.130.1 to 239.10.131.254239.10.131.255510
67239.10.132.0/23239.10.132.1 to 239.10.133.254239.10.133.255510
68239.10.134.0/23239.10.134.1 to 239.10.135.254239.10.135.255510
69239.10.136.0/23239.10.136.1 to 239.10.137.254239.10.137.255510
70239.10.138.0/23239.10.138.1 to 239.10.139.254239.10.139.255510
71239.10.140.0/23239.10.140.1 to 239.10.141.254239.10.141.255510
72239.10.142.0/23239.10.142.1 to 239.10.143.254239.10.143.255510
73239.10.144.0/23239.10.144.1 to 239.10.145.254239.10.145.255510
74239.10.146.0/23239.10.146.1 to 239.10.147.254239.10.147.255510
75239.10.148.0/23239.10.148.1 to 239.10.149.254239.10.149.255510
76239.10.150.0/23239.10.150.1 to 239.10.151.254239.10.151.255510
77239.10.152.0/23239.10.152.1 to 239.10.153.254239.10.153.255510
78239.10.154.0/23239.10.154.1 to 239.10.155.254239.10.155.255510
79239.10.156.0/23239.10.156.1 to 239.10.157.254239.10.157.255510
80239.10.158.0/23239.10.158.1 to 239.10.159.254239.10.159.255510
81239.10.160.0/23239.10.160.1 to 239.10.161.254239.10.161.255510
82239.10.162.0/23239.10.162.1 to 239.10.163.254239.10.163.255510
83239.10.164.0/23239.10.164.1 to 239.10.165.254239.10.165.255510
84239.10.166.0/23239.10.166.1 to 239.10.167.254239.10.167.255510
85239.10.168.0/23239.10.168.1 to 239.10.169.254239.10.169.255510
86239.10.170.0/23239.10.170.1 to 239.10.171.254239.10.171.255510
87239.10.172.0/23239.10.172.1 to 239.10.173.254239.10.173.255510
88239.10.174.0/23239.10.174.1 to 239.10.175.254239.10.175.255510
89239.10.176.0/23239.10.176.1 to 239.10.177.254239.10.177.255510
90239.10.178.0/23239.10.178.1 to 239.10.179.254239.10.179.255510
91239.10.180.0/23239.10.180.1 to 239.10.181.254239.10.181.255510
92239.10.182.0/23239.10.182.1 to 239.10.183.254239.10.183.255510
93239.10.184.0/23239.10.184.1 to 239.10.185.254239.10.185.255510
94239.10.186.0/23239.10.186.1 to 239.10.187.254239.10.187.255510
95239.10.188.0/23239.10.188.1 to 239.10.189.254239.10.189.255510
96239.10.190.0/23239.10.190.1 to 239.10.191.254239.10.191.255510
97239.10.192.0/23239.10.192.1 to 239.10.193.254239.10.193.255510
98239.10.194.0/23239.10.194.1 to 239.10.195.254239.10.195.255510
99239.10.196.0/23239.10.196.1 to 239.10.197.254239.10.197.255510
100239.10.198.0/23239.10.198.1 to 239.10.199.254239.10.199.255510
101239.10.200.0/23239.10.200.1 to 239.10.201.254239.10.201.255510
102239.10.202.0/23239.10.202.1 to 239.10.203.254239.10.203.255510
103239.10.204.0/23239.10.204.1 to 239.10.205.254239.10.205.255510
104239.10.206.0/23239.10.206.1 to 239.10.207.254239.10.207.255510
105239.10.208.0/23239.10.208.1 to 239.10.209.254239.10.209.255510
106239.10.210.0/23239.10.210.1 to 239.10.211.254239.10.211.255510
107239.10.212.0/23239.10.212.1 to 239.10.213.254239.10.213.255510
108239.10.214.0/23239.10.214.1 to 239.10.215.254239.10.215.255510
109239.10.216.0/23239.10.216.1 to 239.10.217.254239.10.217.255510
110239.10.218.0/23239.10.218.1 to 239.10.219.254239.10.219.255510
111239.10.220.0/23239.10.220.1 to 239.10.221.254239.10.221.255510
112239.10.222.0/23239.10.222.1 to 239.10.223.254239.10.223.255510
113239.10.224.0/23239.10.224.1 to 239.10.225.254239.10.225.255510
114239.10.226.0/23239.10.226.1 to 239.10.227.254239.10.227.255510
115239.10.228.0/23239.10.228.1 to 239.10.229.254239.10.229.255510
116239.10.230.0/23239.10.230.1 to 239.10.231.254239.10.231.255510
117239.10.232.0/23239.10.232.1 to 239.10.233.254239.10.233.255510
118239.10.234.0/23239.10.234.1 to 239.10.235.254239.10.235.255510
119239.10.236.0/23239.10.236.1 to 239.10.237.254239.10.237.255510
120239.10.238.0/23239.10.238.1 to 239.10.239.254239.10.239.255510
121239.10.240.0/23239.10.240.1 to 239.10.241.254239.10.241.255510
122239.10.242.0/23239.10.242.1 to 239.10.243.254239.10.243.255510
123239.10.244.0/23239.10.244.1 to 239.10.245.254239.10.245.255510
124239.10.246.0/23239.10.246.1 to 239.10.247.254239.10.247.255510
125239.10.248.0/23239.10.248.1 to 239.10.249.254239.10.249.255510
126239.10.250.0/23239.10.250.1 to 239.10.251.254239.10.251.255510
127239.10.252.0/23239.10.252.1 to 239.10.253.254239.10.253.255510
128239.10.254.0/23239.10.254.1 to 239.10.255.254239.10.255.255510
129239.11.0.0/23239.11.0.1 to 239.11.1.254239.11.1.255510
130239.11.2.0/23239.11.2.1 to 239.11.3.254239.11.3.255510
131239.11.4.0/23239.11.4.1 to 239.11.5.254239.11.5.255510
132239.11.6.0/23239.11.6.1 to 239.11.7.254239.11.7.255510
133239.11.8.0/23239.11.8.1 to 239.11.9.254239.11.9.255510
134239.11.10.0/23239.11.10.1 to 239.11.11.254239.11.11.255510
135239.11.12.0/23239.11.12.1 to 239.11.13.254239.11.13.255510
136239.11.14.0/23239.11.14.1 to 239.11.15.254239.11.15.255510
137239.11.16.0/23239.11.16.1 to 239.11.17.254239.11.17.255510
138239.11.18.0/23239.11.18.1 to 239.11.19.254239.11.19.255510
139239.11.20.0/23239.11.20.1 to 239.11.21.254239.11.21.255510
140239.11.22.0/23239.11.22.1 to 239.11.23.254239.11.23.255510
141239.11.24.0/23239.11.24.1 to 239.11.25.254239.11.25.255510
142239.11.26.0/23239.11.26.1 to 239.11.27.254239.11.27.255510
143239.11.28.0/23239.11.28.1 to 239.11.29.254239.11.29.255510
144239.11.30.0/23239.11.30.1 to 239.11.31.254239.11.31.255510
145239.11.32.0/23239.11.32.1 to 239.11.33.254239.11.33.255510
146239.11.34.0/23239.11.34.1 to 239.11.35.254239.11.35.255510
147239.11.36.0/23239.11.36.1 to 239.11.37.254239.11.37.255510
148239.11.38.0/23239.11.38.1 to 239.11.39.254239.11.39.255510
149239.11.40.0/23239.11.40.1 to 239.11.41.254239.11.41.255510
150239.11.42.0/23239.11.42.1 to 239.11.43.254239.11.43.255510
151239.11.44.0/23239.11.44.1 to 239.11.45.254239.11.45.255510
152239.11.46.0/23239.11.46.1 to 239.11.47.254239.11.47.255510
153239.11.48.0/23239.11.48.1 to 239.11.49.254239.11.49.255510
154239.11.50.0/23239.11.50.1 to 239.11.51.254239.11.51.255510
155239.11.52.0/23239.11.52.1 to 239.11.53.254239.11.53.255510
156239.11.54.0/23239.11.54.1 to 239.11.55.254239.11.55.255510
157239.11.56.0/23239.11.56.1 to 239.11.57.254239.11.57.255510
158239.11.58.0/23239.11.58.1 to 239.11.59.254239.11.59.255510
159239.11.60.0/23239.11.60.1 to 239.11.61.254239.11.61.255510
160239.11.62.0/23239.11.62.1 to 239.11.63.254239.11.63.255510
161239.11.64.0/23239.11.64.1 to 239.11.65.254239.11.65.255510
162239.11.66.0/23239.11.66.1 to 239.11.67.254239.11.67.255510
163239.11.68.0/23239.11.68.1 to 239.11.69.254239.11.69.255510
164239.11.70.0/23239.11.70.1 to 239.11.71.254239.11.71.255510
165239.11.72.0/23239.11.72.1 to 239.11.73.254239.11.73.255510
166239.11.74.0/23239.11.74.1 to 239.11.75.254239.11.75.255510
167239.11.76.0/23239.11.76.1 to 239.11.77.254239.11.77.255510
168239.11.78.0/23239.11.78.1 to 239.11.79.254239.11.79.255510
169239.11.80.0/23239.11.80.1 to 239.11.81.254239.11.81.255510
170239.11.82.0/23239.11.82.1 to 239.11.83.254239.11.83.255510
171239.11.84.0/23239.11.84.1 to 239.11.85.254239.11.85.255510
172239.11.86.0/23239.11.86.1 to 239.11.87.254239.11.87.255510
173239.11.88.0/23239.11.88.1 to 239.11.89.254239.11.89.255510
174239.11.90.0/23239.11.90.1 to 239.11.91.254239.11.91.255510
175239.11.92.0/23239.11.92.1 to 239.11.93.254239.11.93.255510
176239.11.94.0/23239.11.94.1 to 239.11.95.254239.11.95.255510
177239.11.96.0/23239.11.96.1 to 239.11.97.254239.11.97.255510
178239.11.98.0/23239.11.98.1 to 239.11.99.254239.11.99.255510
179239.11.100.0/23239.11.100.1 to 239.11.101.254239.11.101.255510
180239.11.102.0/23239.11.102.1 to 239.11.103.254239.11.103.255510
181239.11.104.0/23239.11.104.1 to 239.11.105.254239.11.105.255510
182239.11.106.0/23239.11.106.1 to 239.11.107.254239.11.107.255510
183239.11.108.0/23239.11.108.1 to 239.11.109.254239.11.109.255510
184239.11.110.0/23239.11.110.1 to 239.11.111.254239.11.111.255510
185239.11.112.0/23239.11.112.1 to 239.11.113.254239.11.113.255510
186239.11.114.0/23239.11.114.1 to 239.11.115.254239.11.115.255510
187239.11.116.0/23239.11.116.1 to 239.11.117.254239.11.117.255510
188239.11.118.0/23239.11.118.1 to 239.11.119.254239.11.119.255510
189239.11.120.0/23239.11.120.1 to 239.11.121.254239.11.121.255510
190239.11.122.0/23239.11.122.1 to 239.11.123.254239.11.123.255510
191239.11.124.0/23239.11.124.1 to 239.11.125.254239.11.125.255510
192239.11.126.0/23239.11.126.1 to 239.11.127.254239.11.127.255510
193239.11.128.0/23239.11.128.1 to 239.11.129.254239.11.129.255510
194239.11.130.0/23239.11.130.1 to 239.11.131.254239.11.131.255510
195239.11.132.0/23239.11.132.1 to 239.11.133.254239.11.133.255510
196239.11.134.0/23239.11.134.1 to 239.11.135.254239.11.135.255510
197239.11.136.0/23239.11.136.1 to 239.11.137.254239.11.137.255510
198239.11.138.0/23239.11.138.1 to 239.11.139.254239.11.139.255510
199239.11.140.0/23239.11.140.1 to 239.11.141.254239.11.141.255510
200239.11.142.0/23239.11.142.1 to 239.11.143.254239.11.143.255510
201239.11.144.0/23239.11.144.1 to 239.11.145.254239.11.145.255510
202239.11.146.0/23239.11.146.1 to 239.11.147.254239.11.147.255510
203239.11.148.0/23239.11.148.1 to 239.11.149.254239.11.149.255510
204239.11.150.0/23239.11.150.1 to 239.11.151.254239.11.151.255510
205239.11.152.0/23239.11.152.1 to 239.11.153.254239.11.153.255510
206239.11.154.0/23239.11.154.1 to 239.11.155.254239.11.155.255510
207239.11.156.0/23239.11.156.1 to 239.11.157.254239.11.157.255510
208239.11.158.0/23239.11.158.1 to 239.11.159.254239.11.159.255510
209239.11.160.0/23239.11.160.1 to 239.11.161.254239.11.161.255510
210239.11.162.0/23239.11.162.1 to 239.11.163.254239.11.163.255510
211239.11.164.0/23239.11.164.1 to 239.11.165.254239.11.165.255510
212239.11.166.0/23239.11.166.1 to 239.11.167.254239.11.167.255510
213239.11.168.0/23239.11.168.1 to 239.11.169.254239.11.169.255510
214239.11.170.0/23239.11.170.1 to 239.11.171.254239.11.171.255510
215239.11.172.0/23239.11.172.1 to 239.11.173.254239.11.173.255510
216239.11.174.0/23239.11.174.1 to 239.11.175.254239.11.175.255510
217239.11.176.0/23239.11.176.1 to 239.11.177.254239.11.177.255510
218239.11.178.0/23239.11.178.1 to 239.11.179.254239.11.179.255510
219239.11.180.0/23239.11.180.1 to 239.11.181.254239.11.181.255510
220239.11.182.0/23239.11.182.1 to 239.11.183.254239.11.183.255510
221239.11.184.0/23239.11.184.1 to 239.11.185.254239.11.185.255510
222239.11.186.0/23239.11.186.1 to 239.11.187.254239.11.187.255510
223239.11.188.0/23239.11.188.1 to 239.11.189.254239.11.189.255510
224239.11.190.0/23239.11.190.1 to 239.11.191.254239.11.191.255510
225239.11.192.0/23239.11.192.1 to 239.11.193.254239.11.193.255510
226239.11.194.0/23239.11.194.1 to 239.11.195.254239.11.195.255510
227239.11.196.0/23239.11.196.1 to 239.11.197.254239.11.197.255510
228239.11.198.0/23239.11.198.1 to 239.11.199.254239.11.199.255510
229239.11.200.0/23239.11.200.1 to 239.11.201.254239.11.201.255510
230239.11.202.0/23239.11.202.1 to 239.11.203.254239.11.203.255510
231239.11.204.0/23239.11.204.1 to 239.11.205.254239.11.205.255510
232239.11.206.0/23239.11.206.1 to 239.11.207.254239.11.207.255510
233239.11.208.0/23239.11.208.1 to 239.11.209.254239.11.209.255510
234239.11.210.0/23239.11.210.1 to 239.11.211.254239.11.211.255510
235239.11.212.0/23239.11.212.1 to 239.11.213.254239.11.213.255510
236239.11.214.0/23239.11.214.1 to 239.11.215.254239.11.215.255510
237239.11.216.0/23239.11.216.1 to 239.11.217.254239.11.217.255510
238239.11.218.0/23239.11.218.1 to 239.11.219.254239.11.219.255510
239239.11.220.0/23239.11.220.1 to 239.11.221.254239.11.221.255510
240239.11.222.0/23239.11.222.1 to 239.11.223.254239.11.223.255510
241239.11.224.0/23239.11.224.1 to 239.11.225.254239.11.225.255510
242239.11.226.0/23239.11.226.1 to 239.11.227.254239.11.227.255510
243239.11.228.0/23239.11.228.1 to 239.11.229.254239.11.229.255510
244239.11.230.0/23239.11.230.1 to 239.11.231.254239.11.231.255510
245239.11.232.0/23239.11.232.1 to 239.11.233.254239.11.233.255510
246239.11.234.0/23239.11.234.1 to 239.11.235.254239.11.235.255510
247239.11.236.0/23239.11.236.1 to 239.11.237.254239.11.237.255510
248239.11.238.0/23239.11.238.1 to 239.11.239.254239.11.239.255510
249239.11.240.0/23239.11.240.1 to 239.11.241.254239.11.241.255510
250239.11.242.0/23239.11.242.1 to 239.11.243.254239.11.243.255510
251239.11.244.0/23239.11.244.1 to 239.11.245.254239.11.245.255510
252239.11.246.0/23239.11.246.1 to 239.11.247.254239.11.247.255510
253239.11.248.0/23239.11.248.1 to 239.11.249.254239.11.249.255510
254239.11.250.0/23239.11.250.1 to 239.11.251.254239.11.251.255510
255239.11.252.0/23239.11.252.1 to 239.11.253.254239.11.253.255510
256239.11.254.0/23239.11.254.1 to 239.11.255.254239.11.255.255510

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.