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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.

Network225.238.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
225.238.0.0
Broadcast address
225.239.255.255
First usable
225.238.0.1
Last usable
225.239.255.254
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 E1EE0000 · Integer 3790471168 to 3790602239
Reverse DNS zones
238.225.in-addr.arpa
239.225.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
Address11100001.11101110.00000000.00000000225.238.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network11100001.11101110.00000000.00000000225.238.0.0
Broadcast11100001.11101111.11111111.11111111225.239.255.255
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)

225.238.0.0/15 makes 256 subnets of /23.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1225.238.0.0/23225.238.0.1 to 225.238.1.254225.238.1.255510
2225.238.2.0/23225.238.2.1 to 225.238.3.254225.238.3.255510
3225.238.4.0/23225.238.4.1 to 225.238.5.254225.238.5.255510
4225.238.6.0/23225.238.6.1 to 225.238.7.254225.238.7.255510
5225.238.8.0/23225.238.8.1 to 225.238.9.254225.238.9.255510
6225.238.10.0/23225.238.10.1 to 225.238.11.254225.238.11.255510
7225.238.12.0/23225.238.12.1 to 225.238.13.254225.238.13.255510
8225.238.14.0/23225.238.14.1 to 225.238.15.254225.238.15.255510
9225.238.16.0/23225.238.16.1 to 225.238.17.254225.238.17.255510
10225.238.18.0/23225.238.18.1 to 225.238.19.254225.238.19.255510
11225.238.20.0/23225.238.20.1 to 225.238.21.254225.238.21.255510
12225.238.22.0/23225.238.22.1 to 225.238.23.254225.238.23.255510
13225.238.24.0/23225.238.24.1 to 225.238.25.254225.238.25.255510
14225.238.26.0/23225.238.26.1 to 225.238.27.254225.238.27.255510
15225.238.28.0/23225.238.28.1 to 225.238.29.254225.238.29.255510
16225.238.30.0/23225.238.30.1 to 225.238.31.254225.238.31.255510
17225.238.32.0/23225.238.32.1 to 225.238.33.254225.238.33.255510
18225.238.34.0/23225.238.34.1 to 225.238.35.254225.238.35.255510
19225.238.36.0/23225.238.36.1 to 225.238.37.254225.238.37.255510
20225.238.38.0/23225.238.38.1 to 225.238.39.254225.238.39.255510
21225.238.40.0/23225.238.40.1 to 225.238.41.254225.238.41.255510
22225.238.42.0/23225.238.42.1 to 225.238.43.254225.238.43.255510
23225.238.44.0/23225.238.44.1 to 225.238.45.254225.238.45.255510
24225.238.46.0/23225.238.46.1 to 225.238.47.254225.238.47.255510
25225.238.48.0/23225.238.48.1 to 225.238.49.254225.238.49.255510
26225.238.50.0/23225.238.50.1 to 225.238.51.254225.238.51.255510
27225.238.52.0/23225.238.52.1 to 225.238.53.254225.238.53.255510
28225.238.54.0/23225.238.54.1 to 225.238.55.254225.238.55.255510
29225.238.56.0/23225.238.56.1 to 225.238.57.254225.238.57.255510
30225.238.58.0/23225.238.58.1 to 225.238.59.254225.238.59.255510
31225.238.60.0/23225.238.60.1 to 225.238.61.254225.238.61.255510
32225.238.62.0/23225.238.62.1 to 225.238.63.254225.238.63.255510
33225.238.64.0/23225.238.64.1 to 225.238.65.254225.238.65.255510
34225.238.66.0/23225.238.66.1 to 225.238.67.254225.238.67.255510
35225.238.68.0/23225.238.68.1 to 225.238.69.254225.238.69.255510
36225.238.70.0/23225.238.70.1 to 225.238.71.254225.238.71.255510
37225.238.72.0/23225.238.72.1 to 225.238.73.254225.238.73.255510
38225.238.74.0/23225.238.74.1 to 225.238.75.254225.238.75.255510
39225.238.76.0/23225.238.76.1 to 225.238.77.254225.238.77.255510
40225.238.78.0/23225.238.78.1 to 225.238.79.254225.238.79.255510
41225.238.80.0/23225.238.80.1 to 225.238.81.254225.238.81.255510
42225.238.82.0/23225.238.82.1 to 225.238.83.254225.238.83.255510
43225.238.84.0/23225.238.84.1 to 225.238.85.254225.238.85.255510
44225.238.86.0/23225.238.86.1 to 225.238.87.254225.238.87.255510
45225.238.88.0/23225.238.88.1 to 225.238.89.254225.238.89.255510
46225.238.90.0/23225.238.90.1 to 225.238.91.254225.238.91.255510
47225.238.92.0/23225.238.92.1 to 225.238.93.254225.238.93.255510
48225.238.94.0/23225.238.94.1 to 225.238.95.254225.238.95.255510
49225.238.96.0/23225.238.96.1 to 225.238.97.254225.238.97.255510
50225.238.98.0/23225.238.98.1 to 225.238.99.254225.238.99.255510
51225.238.100.0/23225.238.100.1 to 225.238.101.254225.238.101.255510
52225.238.102.0/23225.238.102.1 to 225.238.103.254225.238.103.255510
53225.238.104.0/23225.238.104.1 to 225.238.105.254225.238.105.255510
54225.238.106.0/23225.238.106.1 to 225.238.107.254225.238.107.255510
55225.238.108.0/23225.238.108.1 to 225.238.109.254225.238.109.255510
56225.238.110.0/23225.238.110.1 to 225.238.111.254225.238.111.255510
57225.238.112.0/23225.238.112.1 to 225.238.113.254225.238.113.255510
58225.238.114.0/23225.238.114.1 to 225.238.115.254225.238.115.255510
59225.238.116.0/23225.238.116.1 to 225.238.117.254225.238.117.255510
60225.238.118.0/23225.238.118.1 to 225.238.119.254225.238.119.255510
61225.238.120.0/23225.238.120.1 to 225.238.121.254225.238.121.255510
62225.238.122.0/23225.238.122.1 to 225.238.123.254225.238.123.255510
63225.238.124.0/23225.238.124.1 to 225.238.125.254225.238.125.255510
64225.238.126.0/23225.238.126.1 to 225.238.127.254225.238.127.255510
65225.238.128.0/23225.238.128.1 to 225.238.129.254225.238.129.255510
66225.238.130.0/23225.238.130.1 to 225.238.131.254225.238.131.255510
67225.238.132.0/23225.238.132.1 to 225.238.133.254225.238.133.255510
68225.238.134.0/23225.238.134.1 to 225.238.135.254225.238.135.255510
69225.238.136.0/23225.238.136.1 to 225.238.137.254225.238.137.255510
70225.238.138.0/23225.238.138.1 to 225.238.139.254225.238.139.255510
71225.238.140.0/23225.238.140.1 to 225.238.141.254225.238.141.255510
72225.238.142.0/23225.238.142.1 to 225.238.143.254225.238.143.255510
73225.238.144.0/23225.238.144.1 to 225.238.145.254225.238.145.255510
74225.238.146.0/23225.238.146.1 to 225.238.147.254225.238.147.255510
75225.238.148.0/23225.238.148.1 to 225.238.149.254225.238.149.255510
76225.238.150.0/23225.238.150.1 to 225.238.151.254225.238.151.255510
77225.238.152.0/23225.238.152.1 to 225.238.153.254225.238.153.255510
78225.238.154.0/23225.238.154.1 to 225.238.155.254225.238.155.255510
79225.238.156.0/23225.238.156.1 to 225.238.157.254225.238.157.255510
80225.238.158.0/23225.238.158.1 to 225.238.159.254225.238.159.255510
81225.238.160.0/23225.238.160.1 to 225.238.161.254225.238.161.255510
82225.238.162.0/23225.238.162.1 to 225.238.163.254225.238.163.255510
83225.238.164.0/23225.238.164.1 to 225.238.165.254225.238.165.255510
84225.238.166.0/23225.238.166.1 to 225.238.167.254225.238.167.255510
85225.238.168.0/23225.238.168.1 to 225.238.169.254225.238.169.255510
86225.238.170.0/23225.238.170.1 to 225.238.171.254225.238.171.255510
87225.238.172.0/23225.238.172.1 to 225.238.173.254225.238.173.255510
88225.238.174.0/23225.238.174.1 to 225.238.175.254225.238.175.255510
89225.238.176.0/23225.238.176.1 to 225.238.177.254225.238.177.255510
90225.238.178.0/23225.238.178.1 to 225.238.179.254225.238.179.255510
91225.238.180.0/23225.238.180.1 to 225.238.181.254225.238.181.255510
92225.238.182.0/23225.238.182.1 to 225.238.183.254225.238.183.255510
93225.238.184.0/23225.238.184.1 to 225.238.185.254225.238.185.255510
94225.238.186.0/23225.238.186.1 to 225.238.187.254225.238.187.255510
95225.238.188.0/23225.238.188.1 to 225.238.189.254225.238.189.255510
96225.238.190.0/23225.238.190.1 to 225.238.191.254225.238.191.255510
97225.238.192.0/23225.238.192.1 to 225.238.193.254225.238.193.255510
98225.238.194.0/23225.238.194.1 to 225.238.195.254225.238.195.255510
99225.238.196.0/23225.238.196.1 to 225.238.197.254225.238.197.255510
100225.238.198.0/23225.238.198.1 to 225.238.199.254225.238.199.255510
101225.238.200.0/23225.238.200.1 to 225.238.201.254225.238.201.255510
102225.238.202.0/23225.238.202.1 to 225.238.203.254225.238.203.255510
103225.238.204.0/23225.238.204.1 to 225.238.205.254225.238.205.255510
104225.238.206.0/23225.238.206.1 to 225.238.207.254225.238.207.255510
105225.238.208.0/23225.238.208.1 to 225.238.209.254225.238.209.255510
106225.238.210.0/23225.238.210.1 to 225.238.211.254225.238.211.255510
107225.238.212.0/23225.238.212.1 to 225.238.213.254225.238.213.255510
108225.238.214.0/23225.238.214.1 to 225.238.215.254225.238.215.255510
109225.238.216.0/23225.238.216.1 to 225.238.217.254225.238.217.255510
110225.238.218.0/23225.238.218.1 to 225.238.219.254225.238.219.255510
111225.238.220.0/23225.238.220.1 to 225.238.221.254225.238.221.255510
112225.238.222.0/23225.238.222.1 to 225.238.223.254225.238.223.255510
113225.238.224.0/23225.238.224.1 to 225.238.225.254225.238.225.255510
114225.238.226.0/23225.238.226.1 to 225.238.227.254225.238.227.255510
115225.238.228.0/23225.238.228.1 to 225.238.229.254225.238.229.255510
116225.238.230.0/23225.238.230.1 to 225.238.231.254225.238.231.255510
117225.238.232.0/23225.238.232.1 to 225.238.233.254225.238.233.255510
118225.238.234.0/23225.238.234.1 to 225.238.235.254225.238.235.255510
119225.238.236.0/23225.238.236.1 to 225.238.237.254225.238.237.255510
120225.238.238.0/23225.238.238.1 to 225.238.239.254225.238.239.255510
121225.238.240.0/23225.238.240.1 to 225.238.241.254225.238.241.255510
122225.238.242.0/23225.238.242.1 to 225.238.243.254225.238.243.255510
123225.238.244.0/23225.238.244.1 to 225.238.245.254225.238.245.255510
124225.238.246.0/23225.238.246.1 to 225.238.247.254225.238.247.255510
125225.238.248.0/23225.238.248.1 to 225.238.249.254225.238.249.255510
126225.238.250.0/23225.238.250.1 to 225.238.251.254225.238.251.255510
127225.238.252.0/23225.238.252.1 to 225.238.253.254225.238.253.255510
128225.238.254.0/23225.238.254.1 to 225.238.255.254225.238.255.255510
129225.239.0.0/23225.239.0.1 to 225.239.1.254225.239.1.255510
130225.239.2.0/23225.239.2.1 to 225.239.3.254225.239.3.255510
131225.239.4.0/23225.239.4.1 to 225.239.5.254225.239.5.255510
132225.239.6.0/23225.239.6.1 to 225.239.7.254225.239.7.255510
133225.239.8.0/23225.239.8.1 to 225.239.9.254225.239.9.255510
134225.239.10.0/23225.239.10.1 to 225.239.11.254225.239.11.255510
135225.239.12.0/23225.239.12.1 to 225.239.13.254225.239.13.255510
136225.239.14.0/23225.239.14.1 to 225.239.15.254225.239.15.255510
137225.239.16.0/23225.239.16.1 to 225.239.17.254225.239.17.255510
138225.239.18.0/23225.239.18.1 to 225.239.19.254225.239.19.255510
139225.239.20.0/23225.239.20.1 to 225.239.21.254225.239.21.255510
140225.239.22.0/23225.239.22.1 to 225.239.23.254225.239.23.255510
141225.239.24.0/23225.239.24.1 to 225.239.25.254225.239.25.255510
142225.239.26.0/23225.239.26.1 to 225.239.27.254225.239.27.255510
143225.239.28.0/23225.239.28.1 to 225.239.29.254225.239.29.255510
144225.239.30.0/23225.239.30.1 to 225.239.31.254225.239.31.255510
145225.239.32.0/23225.239.32.1 to 225.239.33.254225.239.33.255510
146225.239.34.0/23225.239.34.1 to 225.239.35.254225.239.35.255510
147225.239.36.0/23225.239.36.1 to 225.239.37.254225.239.37.255510
148225.239.38.0/23225.239.38.1 to 225.239.39.254225.239.39.255510
149225.239.40.0/23225.239.40.1 to 225.239.41.254225.239.41.255510
150225.239.42.0/23225.239.42.1 to 225.239.43.254225.239.43.255510
151225.239.44.0/23225.239.44.1 to 225.239.45.254225.239.45.255510
152225.239.46.0/23225.239.46.1 to 225.239.47.254225.239.47.255510
153225.239.48.0/23225.239.48.1 to 225.239.49.254225.239.49.255510
154225.239.50.0/23225.239.50.1 to 225.239.51.254225.239.51.255510
155225.239.52.0/23225.239.52.1 to 225.239.53.254225.239.53.255510
156225.239.54.0/23225.239.54.1 to 225.239.55.254225.239.55.255510
157225.239.56.0/23225.239.56.1 to 225.239.57.254225.239.57.255510
158225.239.58.0/23225.239.58.1 to 225.239.59.254225.239.59.255510
159225.239.60.0/23225.239.60.1 to 225.239.61.254225.239.61.255510
160225.239.62.0/23225.239.62.1 to 225.239.63.254225.239.63.255510
161225.239.64.0/23225.239.64.1 to 225.239.65.254225.239.65.255510
162225.239.66.0/23225.239.66.1 to 225.239.67.254225.239.67.255510
163225.239.68.0/23225.239.68.1 to 225.239.69.254225.239.69.255510
164225.239.70.0/23225.239.70.1 to 225.239.71.254225.239.71.255510
165225.239.72.0/23225.239.72.1 to 225.239.73.254225.239.73.255510
166225.239.74.0/23225.239.74.1 to 225.239.75.254225.239.75.255510
167225.239.76.0/23225.239.76.1 to 225.239.77.254225.239.77.255510
168225.239.78.0/23225.239.78.1 to 225.239.79.254225.239.79.255510
169225.239.80.0/23225.239.80.1 to 225.239.81.254225.239.81.255510
170225.239.82.0/23225.239.82.1 to 225.239.83.254225.239.83.255510
171225.239.84.0/23225.239.84.1 to 225.239.85.254225.239.85.255510
172225.239.86.0/23225.239.86.1 to 225.239.87.254225.239.87.255510
173225.239.88.0/23225.239.88.1 to 225.239.89.254225.239.89.255510
174225.239.90.0/23225.239.90.1 to 225.239.91.254225.239.91.255510
175225.239.92.0/23225.239.92.1 to 225.239.93.254225.239.93.255510
176225.239.94.0/23225.239.94.1 to 225.239.95.254225.239.95.255510
177225.239.96.0/23225.239.96.1 to 225.239.97.254225.239.97.255510
178225.239.98.0/23225.239.98.1 to 225.239.99.254225.239.99.255510
179225.239.100.0/23225.239.100.1 to 225.239.101.254225.239.101.255510
180225.239.102.0/23225.239.102.1 to 225.239.103.254225.239.103.255510
181225.239.104.0/23225.239.104.1 to 225.239.105.254225.239.105.255510
182225.239.106.0/23225.239.106.1 to 225.239.107.254225.239.107.255510
183225.239.108.0/23225.239.108.1 to 225.239.109.254225.239.109.255510
184225.239.110.0/23225.239.110.1 to 225.239.111.254225.239.111.255510
185225.239.112.0/23225.239.112.1 to 225.239.113.254225.239.113.255510
186225.239.114.0/23225.239.114.1 to 225.239.115.254225.239.115.255510
187225.239.116.0/23225.239.116.1 to 225.239.117.254225.239.117.255510
188225.239.118.0/23225.239.118.1 to 225.239.119.254225.239.119.255510
189225.239.120.0/23225.239.120.1 to 225.239.121.254225.239.121.255510
190225.239.122.0/23225.239.122.1 to 225.239.123.254225.239.123.255510
191225.239.124.0/23225.239.124.1 to 225.239.125.254225.239.125.255510
192225.239.126.0/23225.239.126.1 to 225.239.127.254225.239.127.255510
193225.239.128.0/23225.239.128.1 to 225.239.129.254225.239.129.255510
194225.239.130.0/23225.239.130.1 to 225.239.131.254225.239.131.255510
195225.239.132.0/23225.239.132.1 to 225.239.133.254225.239.133.255510
196225.239.134.0/23225.239.134.1 to 225.239.135.254225.239.135.255510
197225.239.136.0/23225.239.136.1 to 225.239.137.254225.239.137.255510
198225.239.138.0/23225.239.138.1 to 225.239.139.254225.239.139.255510
199225.239.140.0/23225.239.140.1 to 225.239.141.254225.239.141.255510
200225.239.142.0/23225.239.142.1 to 225.239.143.254225.239.143.255510
201225.239.144.0/23225.239.144.1 to 225.239.145.254225.239.145.255510
202225.239.146.0/23225.239.146.1 to 225.239.147.254225.239.147.255510
203225.239.148.0/23225.239.148.1 to 225.239.149.254225.239.149.255510
204225.239.150.0/23225.239.150.1 to 225.239.151.254225.239.151.255510
205225.239.152.0/23225.239.152.1 to 225.239.153.254225.239.153.255510
206225.239.154.0/23225.239.154.1 to 225.239.155.254225.239.155.255510
207225.239.156.0/23225.239.156.1 to 225.239.157.254225.239.157.255510
208225.239.158.0/23225.239.158.1 to 225.239.159.254225.239.159.255510
209225.239.160.0/23225.239.160.1 to 225.239.161.254225.239.161.255510
210225.239.162.0/23225.239.162.1 to 225.239.163.254225.239.163.255510
211225.239.164.0/23225.239.164.1 to 225.239.165.254225.239.165.255510
212225.239.166.0/23225.239.166.1 to 225.239.167.254225.239.167.255510
213225.239.168.0/23225.239.168.1 to 225.239.169.254225.239.169.255510
214225.239.170.0/23225.239.170.1 to 225.239.171.254225.239.171.255510
215225.239.172.0/23225.239.172.1 to 225.239.173.254225.239.173.255510
216225.239.174.0/23225.239.174.1 to 225.239.175.254225.239.175.255510
217225.239.176.0/23225.239.176.1 to 225.239.177.254225.239.177.255510
218225.239.178.0/23225.239.178.1 to 225.239.179.254225.239.179.255510
219225.239.180.0/23225.239.180.1 to 225.239.181.254225.239.181.255510
220225.239.182.0/23225.239.182.1 to 225.239.183.254225.239.183.255510
221225.239.184.0/23225.239.184.1 to 225.239.185.254225.239.185.255510
222225.239.186.0/23225.239.186.1 to 225.239.187.254225.239.187.255510
223225.239.188.0/23225.239.188.1 to 225.239.189.254225.239.189.255510
224225.239.190.0/23225.239.190.1 to 225.239.191.254225.239.191.255510
225225.239.192.0/23225.239.192.1 to 225.239.193.254225.239.193.255510
226225.239.194.0/23225.239.194.1 to 225.239.195.254225.239.195.255510
227225.239.196.0/23225.239.196.1 to 225.239.197.254225.239.197.255510
228225.239.198.0/23225.239.198.1 to 225.239.199.254225.239.199.255510
229225.239.200.0/23225.239.200.1 to 225.239.201.254225.239.201.255510
230225.239.202.0/23225.239.202.1 to 225.239.203.254225.239.203.255510
231225.239.204.0/23225.239.204.1 to 225.239.205.254225.239.205.255510
232225.239.206.0/23225.239.206.1 to 225.239.207.254225.239.207.255510
233225.239.208.0/23225.239.208.1 to 225.239.209.254225.239.209.255510
234225.239.210.0/23225.239.210.1 to 225.239.211.254225.239.211.255510
235225.239.212.0/23225.239.212.1 to 225.239.213.254225.239.213.255510
236225.239.214.0/23225.239.214.1 to 225.239.215.254225.239.215.255510
237225.239.216.0/23225.239.216.1 to 225.239.217.254225.239.217.255510
238225.239.218.0/23225.239.218.1 to 225.239.219.254225.239.219.255510
239225.239.220.0/23225.239.220.1 to 225.239.221.254225.239.221.255510
240225.239.222.0/23225.239.222.1 to 225.239.223.254225.239.223.255510
241225.239.224.0/23225.239.224.1 to 225.239.225.254225.239.225.255510
242225.239.226.0/23225.239.226.1 to 225.239.227.254225.239.227.255510
243225.239.228.0/23225.239.228.1 to 225.239.229.254225.239.229.255510
244225.239.230.0/23225.239.230.1 to 225.239.231.254225.239.231.255510
245225.239.232.0/23225.239.232.1 to 225.239.233.254225.239.233.255510
246225.239.234.0/23225.239.234.1 to 225.239.235.254225.239.235.255510
247225.239.236.0/23225.239.236.1 to 225.239.237.254225.239.237.255510
248225.239.238.0/23225.239.238.1 to 225.239.239.254225.239.239.255510
249225.239.240.0/23225.239.240.1 to 225.239.241.254225.239.241.255510
250225.239.242.0/23225.239.242.1 to 225.239.243.254225.239.243.255510
251225.239.244.0/23225.239.244.1 to 225.239.245.254225.239.245.255510
252225.239.246.0/23225.239.246.1 to 225.239.247.254225.239.247.255510
253225.239.248.0/23225.239.248.1 to 225.239.249.254225.239.249.255510
254225.239.250.0/23225.239.250.1 to 225.239.251.254225.239.251.255510
255225.239.252.0/23225.239.252.1 to 225.239.253.254225.239.253.255510
256225.239.254.0/23225.239.254.1 to 225.239.255.254225.239.255.255510

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.