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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.

Network231.192.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
231.192.0.0
Broadcast address
231.199.255.255
First usable
231.192.0.1
Last usable
231.199.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E7C00000 · Integer 3888119808 to 3888644095
Reverse DNS zones
192.231.in-addr.arpa
193.231.in-addr.arpa
194.231.in-addr.arpa
195.231.in-addr.arpa
196.231.in-addr.arpa
197.231.in-addr.arpa
198.231.in-addr.arpa
199.231.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11100111.11000000.00000000.00000000231.192.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network11100111.11000000.00000000.00000000231.192.0.0
Broadcast11100111.11000111.11111111.11111111231.199.255.255
Split into smaller subnets/23
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

231.192.0.0/13 makes 1,024 subnets of /23; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1231.192.0.0/23231.192.0.1 to 231.192.1.254231.192.1.255510
2231.192.2.0/23231.192.2.1 to 231.192.3.254231.192.3.255510
3231.192.4.0/23231.192.4.1 to 231.192.5.254231.192.5.255510
4231.192.6.0/23231.192.6.1 to 231.192.7.254231.192.7.255510
5231.192.8.0/23231.192.8.1 to 231.192.9.254231.192.9.255510
6231.192.10.0/23231.192.10.1 to 231.192.11.254231.192.11.255510
7231.192.12.0/23231.192.12.1 to 231.192.13.254231.192.13.255510
8231.192.14.0/23231.192.14.1 to 231.192.15.254231.192.15.255510
9231.192.16.0/23231.192.16.1 to 231.192.17.254231.192.17.255510
10231.192.18.0/23231.192.18.1 to 231.192.19.254231.192.19.255510
11231.192.20.0/23231.192.20.1 to 231.192.21.254231.192.21.255510
12231.192.22.0/23231.192.22.1 to 231.192.23.254231.192.23.255510
13231.192.24.0/23231.192.24.1 to 231.192.25.254231.192.25.255510
14231.192.26.0/23231.192.26.1 to 231.192.27.254231.192.27.255510
15231.192.28.0/23231.192.28.1 to 231.192.29.254231.192.29.255510
16231.192.30.0/23231.192.30.1 to 231.192.31.254231.192.31.255510
17231.192.32.0/23231.192.32.1 to 231.192.33.254231.192.33.255510
18231.192.34.0/23231.192.34.1 to 231.192.35.254231.192.35.255510
19231.192.36.0/23231.192.36.1 to 231.192.37.254231.192.37.255510
20231.192.38.0/23231.192.38.1 to 231.192.39.254231.192.39.255510
21231.192.40.0/23231.192.40.1 to 231.192.41.254231.192.41.255510
22231.192.42.0/23231.192.42.1 to 231.192.43.254231.192.43.255510
23231.192.44.0/23231.192.44.1 to 231.192.45.254231.192.45.255510
24231.192.46.0/23231.192.46.1 to 231.192.47.254231.192.47.255510
25231.192.48.0/23231.192.48.1 to 231.192.49.254231.192.49.255510
26231.192.50.0/23231.192.50.1 to 231.192.51.254231.192.51.255510
27231.192.52.0/23231.192.52.1 to 231.192.53.254231.192.53.255510
28231.192.54.0/23231.192.54.1 to 231.192.55.254231.192.55.255510
29231.192.56.0/23231.192.56.1 to 231.192.57.254231.192.57.255510
30231.192.58.0/23231.192.58.1 to 231.192.59.254231.192.59.255510
31231.192.60.0/23231.192.60.1 to 231.192.61.254231.192.61.255510
32231.192.62.0/23231.192.62.1 to 231.192.63.254231.192.63.255510
33231.192.64.0/23231.192.64.1 to 231.192.65.254231.192.65.255510
34231.192.66.0/23231.192.66.1 to 231.192.67.254231.192.67.255510
35231.192.68.0/23231.192.68.1 to 231.192.69.254231.192.69.255510
36231.192.70.0/23231.192.70.1 to 231.192.71.254231.192.71.255510
37231.192.72.0/23231.192.72.1 to 231.192.73.254231.192.73.255510
38231.192.74.0/23231.192.74.1 to 231.192.75.254231.192.75.255510
39231.192.76.0/23231.192.76.1 to 231.192.77.254231.192.77.255510
40231.192.78.0/23231.192.78.1 to 231.192.79.254231.192.79.255510
41231.192.80.0/23231.192.80.1 to 231.192.81.254231.192.81.255510
42231.192.82.0/23231.192.82.1 to 231.192.83.254231.192.83.255510
43231.192.84.0/23231.192.84.1 to 231.192.85.254231.192.85.255510
44231.192.86.0/23231.192.86.1 to 231.192.87.254231.192.87.255510
45231.192.88.0/23231.192.88.1 to 231.192.89.254231.192.89.255510
46231.192.90.0/23231.192.90.1 to 231.192.91.254231.192.91.255510
47231.192.92.0/23231.192.92.1 to 231.192.93.254231.192.93.255510
48231.192.94.0/23231.192.94.1 to 231.192.95.254231.192.95.255510
49231.192.96.0/23231.192.96.1 to 231.192.97.254231.192.97.255510
50231.192.98.0/23231.192.98.1 to 231.192.99.254231.192.99.255510
51231.192.100.0/23231.192.100.1 to 231.192.101.254231.192.101.255510
52231.192.102.0/23231.192.102.1 to 231.192.103.254231.192.103.255510
53231.192.104.0/23231.192.104.1 to 231.192.105.254231.192.105.255510
54231.192.106.0/23231.192.106.1 to 231.192.107.254231.192.107.255510
55231.192.108.0/23231.192.108.1 to 231.192.109.254231.192.109.255510
56231.192.110.0/23231.192.110.1 to 231.192.111.254231.192.111.255510
57231.192.112.0/23231.192.112.1 to 231.192.113.254231.192.113.255510
58231.192.114.0/23231.192.114.1 to 231.192.115.254231.192.115.255510
59231.192.116.0/23231.192.116.1 to 231.192.117.254231.192.117.255510
60231.192.118.0/23231.192.118.1 to 231.192.119.254231.192.119.255510
61231.192.120.0/23231.192.120.1 to 231.192.121.254231.192.121.255510
62231.192.122.0/23231.192.122.1 to 231.192.123.254231.192.123.255510
63231.192.124.0/23231.192.124.1 to 231.192.125.254231.192.125.255510
64231.192.126.0/23231.192.126.1 to 231.192.127.254231.192.127.255510
65231.192.128.0/23231.192.128.1 to 231.192.129.254231.192.129.255510
66231.192.130.0/23231.192.130.1 to 231.192.131.254231.192.131.255510
67231.192.132.0/23231.192.132.1 to 231.192.133.254231.192.133.255510
68231.192.134.0/23231.192.134.1 to 231.192.135.254231.192.135.255510
69231.192.136.0/23231.192.136.1 to 231.192.137.254231.192.137.255510
70231.192.138.0/23231.192.138.1 to 231.192.139.254231.192.139.255510
71231.192.140.0/23231.192.140.1 to 231.192.141.254231.192.141.255510
72231.192.142.0/23231.192.142.1 to 231.192.143.254231.192.143.255510
73231.192.144.0/23231.192.144.1 to 231.192.145.254231.192.145.255510
74231.192.146.0/23231.192.146.1 to 231.192.147.254231.192.147.255510
75231.192.148.0/23231.192.148.1 to 231.192.149.254231.192.149.255510
76231.192.150.0/23231.192.150.1 to 231.192.151.254231.192.151.255510
77231.192.152.0/23231.192.152.1 to 231.192.153.254231.192.153.255510
78231.192.154.0/23231.192.154.1 to 231.192.155.254231.192.155.255510
79231.192.156.0/23231.192.156.1 to 231.192.157.254231.192.157.255510
80231.192.158.0/23231.192.158.1 to 231.192.159.254231.192.159.255510
81231.192.160.0/23231.192.160.1 to 231.192.161.254231.192.161.255510
82231.192.162.0/23231.192.162.1 to 231.192.163.254231.192.163.255510
83231.192.164.0/23231.192.164.1 to 231.192.165.254231.192.165.255510
84231.192.166.0/23231.192.166.1 to 231.192.167.254231.192.167.255510
85231.192.168.0/23231.192.168.1 to 231.192.169.254231.192.169.255510
86231.192.170.0/23231.192.170.1 to 231.192.171.254231.192.171.255510
87231.192.172.0/23231.192.172.1 to 231.192.173.254231.192.173.255510
88231.192.174.0/23231.192.174.1 to 231.192.175.254231.192.175.255510
89231.192.176.0/23231.192.176.1 to 231.192.177.254231.192.177.255510
90231.192.178.0/23231.192.178.1 to 231.192.179.254231.192.179.255510
91231.192.180.0/23231.192.180.1 to 231.192.181.254231.192.181.255510
92231.192.182.0/23231.192.182.1 to 231.192.183.254231.192.183.255510
93231.192.184.0/23231.192.184.1 to 231.192.185.254231.192.185.255510
94231.192.186.0/23231.192.186.1 to 231.192.187.254231.192.187.255510
95231.192.188.0/23231.192.188.1 to 231.192.189.254231.192.189.255510
96231.192.190.0/23231.192.190.1 to 231.192.191.254231.192.191.255510
97231.192.192.0/23231.192.192.1 to 231.192.193.254231.192.193.255510
98231.192.194.0/23231.192.194.1 to 231.192.195.254231.192.195.255510
99231.192.196.0/23231.192.196.1 to 231.192.197.254231.192.197.255510
100231.192.198.0/23231.192.198.1 to 231.192.199.254231.192.199.255510
101231.192.200.0/23231.192.200.1 to 231.192.201.254231.192.201.255510
102231.192.202.0/23231.192.202.1 to 231.192.203.254231.192.203.255510
103231.192.204.0/23231.192.204.1 to 231.192.205.254231.192.205.255510
104231.192.206.0/23231.192.206.1 to 231.192.207.254231.192.207.255510
105231.192.208.0/23231.192.208.1 to 231.192.209.254231.192.209.255510
106231.192.210.0/23231.192.210.1 to 231.192.211.254231.192.211.255510
107231.192.212.0/23231.192.212.1 to 231.192.213.254231.192.213.255510
108231.192.214.0/23231.192.214.1 to 231.192.215.254231.192.215.255510
109231.192.216.0/23231.192.216.1 to 231.192.217.254231.192.217.255510
110231.192.218.0/23231.192.218.1 to 231.192.219.254231.192.219.255510
111231.192.220.0/23231.192.220.1 to 231.192.221.254231.192.221.255510
112231.192.222.0/23231.192.222.1 to 231.192.223.254231.192.223.255510
113231.192.224.0/23231.192.224.1 to 231.192.225.254231.192.225.255510
114231.192.226.0/23231.192.226.1 to 231.192.227.254231.192.227.255510
115231.192.228.0/23231.192.228.1 to 231.192.229.254231.192.229.255510
116231.192.230.0/23231.192.230.1 to 231.192.231.254231.192.231.255510
117231.192.232.0/23231.192.232.1 to 231.192.233.254231.192.233.255510
118231.192.234.0/23231.192.234.1 to 231.192.235.254231.192.235.255510
119231.192.236.0/23231.192.236.1 to 231.192.237.254231.192.237.255510
120231.192.238.0/23231.192.238.1 to 231.192.239.254231.192.239.255510
121231.192.240.0/23231.192.240.1 to 231.192.241.254231.192.241.255510
122231.192.242.0/23231.192.242.1 to 231.192.243.254231.192.243.255510
123231.192.244.0/23231.192.244.1 to 231.192.245.254231.192.245.255510
124231.192.246.0/23231.192.246.1 to 231.192.247.254231.192.247.255510
125231.192.248.0/23231.192.248.1 to 231.192.249.254231.192.249.255510
126231.192.250.0/23231.192.250.1 to 231.192.251.254231.192.251.255510
127231.192.252.0/23231.192.252.1 to 231.192.253.254231.192.253.255510
128231.192.254.0/23231.192.254.1 to 231.192.255.254231.192.255.255510
129231.193.0.0/23231.193.0.1 to 231.193.1.254231.193.1.255510
130231.193.2.0/23231.193.2.1 to 231.193.3.254231.193.3.255510
131231.193.4.0/23231.193.4.1 to 231.193.5.254231.193.5.255510
132231.193.6.0/23231.193.6.1 to 231.193.7.254231.193.7.255510
133231.193.8.0/23231.193.8.1 to 231.193.9.254231.193.9.255510
134231.193.10.0/23231.193.10.1 to 231.193.11.254231.193.11.255510
135231.193.12.0/23231.193.12.1 to 231.193.13.254231.193.13.255510
136231.193.14.0/23231.193.14.1 to 231.193.15.254231.193.15.255510
137231.193.16.0/23231.193.16.1 to 231.193.17.254231.193.17.255510
138231.193.18.0/23231.193.18.1 to 231.193.19.254231.193.19.255510
139231.193.20.0/23231.193.20.1 to 231.193.21.254231.193.21.255510
140231.193.22.0/23231.193.22.1 to 231.193.23.254231.193.23.255510
141231.193.24.0/23231.193.24.1 to 231.193.25.254231.193.25.255510
142231.193.26.0/23231.193.26.1 to 231.193.27.254231.193.27.255510
143231.193.28.0/23231.193.28.1 to 231.193.29.254231.193.29.255510
144231.193.30.0/23231.193.30.1 to 231.193.31.254231.193.31.255510
145231.193.32.0/23231.193.32.1 to 231.193.33.254231.193.33.255510
146231.193.34.0/23231.193.34.1 to 231.193.35.254231.193.35.255510
147231.193.36.0/23231.193.36.1 to 231.193.37.254231.193.37.255510
148231.193.38.0/23231.193.38.1 to 231.193.39.254231.193.39.255510
149231.193.40.0/23231.193.40.1 to 231.193.41.254231.193.41.255510
150231.193.42.0/23231.193.42.1 to 231.193.43.254231.193.43.255510
151231.193.44.0/23231.193.44.1 to 231.193.45.254231.193.45.255510
152231.193.46.0/23231.193.46.1 to 231.193.47.254231.193.47.255510
153231.193.48.0/23231.193.48.1 to 231.193.49.254231.193.49.255510
154231.193.50.0/23231.193.50.1 to 231.193.51.254231.193.51.255510
155231.193.52.0/23231.193.52.1 to 231.193.53.254231.193.53.255510
156231.193.54.0/23231.193.54.1 to 231.193.55.254231.193.55.255510
157231.193.56.0/23231.193.56.1 to 231.193.57.254231.193.57.255510
158231.193.58.0/23231.193.58.1 to 231.193.59.254231.193.59.255510
159231.193.60.0/23231.193.60.1 to 231.193.61.254231.193.61.255510
160231.193.62.0/23231.193.62.1 to 231.193.63.254231.193.63.255510
161231.193.64.0/23231.193.64.1 to 231.193.65.254231.193.65.255510
162231.193.66.0/23231.193.66.1 to 231.193.67.254231.193.67.255510
163231.193.68.0/23231.193.68.1 to 231.193.69.254231.193.69.255510
164231.193.70.0/23231.193.70.1 to 231.193.71.254231.193.71.255510
165231.193.72.0/23231.193.72.1 to 231.193.73.254231.193.73.255510
166231.193.74.0/23231.193.74.1 to 231.193.75.254231.193.75.255510
167231.193.76.0/23231.193.76.1 to 231.193.77.254231.193.77.255510
168231.193.78.0/23231.193.78.1 to 231.193.79.254231.193.79.255510
169231.193.80.0/23231.193.80.1 to 231.193.81.254231.193.81.255510
170231.193.82.0/23231.193.82.1 to 231.193.83.254231.193.83.255510
171231.193.84.0/23231.193.84.1 to 231.193.85.254231.193.85.255510
172231.193.86.0/23231.193.86.1 to 231.193.87.254231.193.87.255510
173231.193.88.0/23231.193.88.1 to 231.193.89.254231.193.89.255510
174231.193.90.0/23231.193.90.1 to 231.193.91.254231.193.91.255510
175231.193.92.0/23231.193.92.1 to 231.193.93.254231.193.93.255510
176231.193.94.0/23231.193.94.1 to 231.193.95.254231.193.95.255510
177231.193.96.0/23231.193.96.1 to 231.193.97.254231.193.97.255510
178231.193.98.0/23231.193.98.1 to 231.193.99.254231.193.99.255510
179231.193.100.0/23231.193.100.1 to 231.193.101.254231.193.101.255510
180231.193.102.0/23231.193.102.1 to 231.193.103.254231.193.103.255510
181231.193.104.0/23231.193.104.1 to 231.193.105.254231.193.105.255510
182231.193.106.0/23231.193.106.1 to 231.193.107.254231.193.107.255510
183231.193.108.0/23231.193.108.1 to 231.193.109.254231.193.109.255510
184231.193.110.0/23231.193.110.1 to 231.193.111.254231.193.111.255510
185231.193.112.0/23231.193.112.1 to 231.193.113.254231.193.113.255510
186231.193.114.0/23231.193.114.1 to 231.193.115.254231.193.115.255510
187231.193.116.0/23231.193.116.1 to 231.193.117.254231.193.117.255510
188231.193.118.0/23231.193.118.1 to 231.193.119.254231.193.119.255510
189231.193.120.0/23231.193.120.1 to 231.193.121.254231.193.121.255510
190231.193.122.0/23231.193.122.1 to 231.193.123.254231.193.123.255510
191231.193.124.0/23231.193.124.1 to 231.193.125.254231.193.125.255510
192231.193.126.0/23231.193.126.1 to 231.193.127.254231.193.127.255510
193231.193.128.0/23231.193.128.1 to 231.193.129.254231.193.129.255510
194231.193.130.0/23231.193.130.1 to 231.193.131.254231.193.131.255510
195231.193.132.0/23231.193.132.1 to 231.193.133.254231.193.133.255510
196231.193.134.0/23231.193.134.1 to 231.193.135.254231.193.135.255510
197231.193.136.0/23231.193.136.1 to 231.193.137.254231.193.137.255510
198231.193.138.0/23231.193.138.1 to 231.193.139.254231.193.139.255510
199231.193.140.0/23231.193.140.1 to 231.193.141.254231.193.141.255510
200231.193.142.0/23231.193.142.1 to 231.193.143.254231.193.143.255510
201231.193.144.0/23231.193.144.1 to 231.193.145.254231.193.145.255510
202231.193.146.0/23231.193.146.1 to 231.193.147.254231.193.147.255510
203231.193.148.0/23231.193.148.1 to 231.193.149.254231.193.149.255510
204231.193.150.0/23231.193.150.1 to 231.193.151.254231.193.151.255510
205231.193.152.0/23231.193.152.1 to 231.193.153.254231.193.153.255510
206231.193.154.0/23231.193.154.1 to 231.193.155.254231.193.155.255510
207231.193.156.0/23231.193.156.1 to 231.193.157.254231.193.157.255510
208231.193.158.0/23231.193.158.1 to 231.193.159.254231.193.159.255510
209231.193.160.0/23231.193.160.1 to 231.193.161.254231.193.161.255510
210231.193.162.0/23231.193.162.1 to 231.193.163.254231.193.163.255510
211231.193.164.0/23231.193.164.1 to 231.193.165.254231.193.165.255510
212231.193.166.0/23231.193.166.1 to 231.193.167.254231.193.167.255510
213231.193.168.0/23231.193.168.1 to 231.193.169.254231.193.169.255510
214231.193.170.0/23231.193.170.1 to 231.193.171.254231.193.171.255510
215231.193.172.0/23231.193.172.1 to 231.193.173.254231.193.173.255510
216231.193.174.0/23231.193.174.1 to 231.193.175.254231.193.175.255510
217231.193.176.0/23231.193.176.1 to 231.193.177.254231.193.177.255510
218231.193.178.0/23231.193.178.1 to 231.193.179.254231.193.179.255510
219231.193.180.0/23231.193.180.1 to 231.193.181.254231.193.181.255510
220231.193.182.0/23231.193.182.1 to 231.193.183.254231.193.183.255510
221231.193.184.0/23231.193.184.1 to 231.193.185.254231.193.185.255510
222231.193.186.0/23231.193.186.1 to 231.193.187.254231.193.187.255510
223231.193.188.0/23231.193.188.1 to 231.193.189.254231.193.189.255510
224231.193.190.0/23231.193.190.1 to 231.193.191.254231.193.191.255510
225231.193.192.0/23231.193.192.1 to 231.193.193.254231.193.193.255510
226231.193.194.0/23231.193.194.1 to 231.193.195.254231.193.195.255510
227231.193.196.0/23231.193.196.1 to 231.193.197.254231.193.197.255510
228231.193.198.0/23231.193.198.1 to 231.193.199.254231.193.199.255510
229231.193.200.0/23231.193.200.1 to 231.193.201.254231.193.201.255510
230231.193.202.0/23231.193.202.1 to 231.193.203.254231.193.203.255510
231231.193.204.0/23231.193.204.1 to 231.193.205.254231.193.205.255510
232231.193.206.0/23231.193.206.1 to 231.193.207.254231.193.207.255510
233231.193.208.0/23231.193.208.1 to 231.193.209.254231.193.209.255510
234231.193.210.0/23231.193.210.1 to 231.193.211.254231.193.211.255510
235231.193.212.0/23231.193.212.1 to 231.193.213.254231.193.213.255510
236231.193.214.0/23231.193.214.1 to 231.193.215.254231.193.215.255510
237231.193.216.0/23231.193.216.1 to 231.193.217.254231.193.217.255510
238231.193.218.0/23231.193.218.1 to 231.193.219.254231.193.219.255510
239231.193.220.0/23231.193.220.1 to 231.193.221.254231.193.221.255510
240231.193.222.0/23231.193.222.1 to 231.193.223.254231.193.223.255510
241231.193.224.0/23231.193.224.1 to 231.193.225.254231.193.225.255510
242231.193.226.0/23231.193.226.1 to 231.193.227.254231.193.227.255510
243231.193.228.0/23231.193.228.1 to 231.193.229.254231.193.229.255510
244231.193.230.0/23231.193.230.1 to 231.193.231.254231.193.231.255510
245231.193.232.0/23231.193.232.1 to 231.193.233.254231.193.233.255510
246231.193.234.0/23231.193.234.1 to 231.193.235.254231.193.235.255510
247231.193.236.0/23231.193.236.1 to 231.193.237.254231.193.237.255510
248231.193.238.0/23231.193.238.1 to 231.193.239.254231.193.239.255510
249231.193.240.0/23231.193.240.1 to 231.193.241.254231.193.241.255510
250231.193.242.0/23231.193.242.1 to 231.193.243.254231.193.243.255510
251231.193.244.0/23231.193.244.1 to 231.193.245.254231.193.245.255510
252231.193.246.0/23231.193.246.1 to 231.193.247.254231.193.247.255510
253231.193.248.0/23231.193.248.1 to 231.193.249.254231.193.249.255510
254231.193.250.0/23231.193.250.1 to 231.193.251.254231.193.251.255510
255231.193.252.0/23231.193.252.1 to 231.193.253.254231.193.253.255510
256231.193.254.0/23231.193.254.1 to 231.193.255.254231.193.255.255510

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.