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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.

Network231.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
231.0.0.0
Broadcast address
231.255.255.255
First usable
231.0.0.1
Last usable
231.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E7000000 · Integer 3875536896 to 3892314111
Reverse DNS zone
231.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11100111..00000000.00000000.00000000231.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network11100111..00000000.00000000.00000000231.0.0.0
Broadcast11100111..11111111.11111111.11111111231.255.255.255
Split into smaller subnets/16
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

231.0.0.0/8 makes 256 subnets of /16.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1231.0.0.0/16231.0.0.1 to 231.0.255.254231.0.255.25565,534
2231.1.0.0/16231.1.0.1 to 231.1.255.254231.1.255.25565,534
3231.2.0.0/16231.2.0.1 to 231.2.255.254231.2.255.25565,534
4231.3.0.0/16231.3.0.1 to 231.3.255.254231.3.255.25565,534
5231.4.0.0/16231.4.0.1 to 231.4.255.254231.4.255.25565,534
6231.5.0.0/16231.5.0.1 to 231.5.255.254231.5.255.25565,534
7231.6.0.0/16231.6.0.1 to 231.6.255.254231.6.255.25565,534
8231.7.0.0/16231.7.0.1 to 231.7.255.254231.7.255.25565,534
9231.8.0.0/16231.8.0.1 to 231.8.255.254231.8.255.25565,534
10231.9.0.0/16231.9.0.1 to 231.9.255.254231.9.255.25565,534
11231.10.0.0/16231.10.0.1 to 231.10.255.254231.10.255.25565,534
12231.11.0.0/16231.11.0.1 to 231.11.255.254231.11.255.25565,534
13231.12.0.0/16231.12.0.1 to 231.12.255.254231.12.255.25565,534
14231.13.0.0/16231.13.0.1 to 231.13.255.254231.13.255.25565,534
15231.14.0.0/16231.14.0.1 to 231.14.255.254231.14.255.25565,534
16231.15.0.0/16231.15.0.1 to 231.15.255.254231.15.255.25565,534
17231.16.0.0/16231.16.0.1 to 231.16.255.254231.16.255.25565,534
18231.17.0.0/16231.17.0.1 to 231.17.255.254231.17.255.25565,534
19231.18.0.0/16231.18.0.1 to 231.18.255.254231.18.255.25565,534
20231.19.0.0/16231.19.0.1 to 231.19.255.254231.19.255.25565,534
21231.20.0.0/16231.20.0.1 to 231.20.255.254231.20.255.25565,534
22231.21.0.0/16231.21.0.1 to 231.21.255.254231.21.255.25565,534
23231.22.0.0/16231.22.0.1 to 231.22.255.254231.22.255.25565,534
24231.23.0.0/16231.23.0.1 to 231.23.255.254231.23.255.25565,534
25231.24.0.0/16231.24.0.1 to 231.24.255.254231.24.255.25565,534
26231.25.0.0/16231.25.0.1 to 231.25.255.254231.25.255.25565,534
27231.26.0.0/16231.26.0.1 to 231.26.255.254231.26.255.25565,534
28231.27.0.0/16231.27.0.1 to 231.27.255.254231.27.255.25565,534
29231.28.0.0/16231.28.0.1 to 231.28.255.254231.28.255.25565,534
30231.29.0.0/16231.29.0.1 to 231.29.255.254231.29.255.25565,534
31231.30.0.0/16231.30.0.1 to 231.30.255.254231.30.255.25565,534
32231.31.0.0/16231.31.0.1 to 231.31.255.254231.31.255.25565,534
33231.32.0.0/16231.32.0.1 to 231.32.255.254231.32.255.25565,534
34231.33.0.0/16231.33.0.1 to 231.33.255.254231.33.255.25565,534
35231.34.0.0/16231.34.0.1 to 231.34.255.254231.34.255.25565,534
36231.35.0.0/16231.35.0.1 to 231.35.255.254231.35.255.25565,534
37231.36.0.0/16231.36.0.1 to 231.36.255.254231.36.255.25565,534
38231.37.0.0/16231.37.0.1 to 231.37.255.254231.37.255.25565,534
39231.38.0.0/16231.38.0.1 to 231.38.255.254231.38.255.25565,534
40231.39.0.0/16231.39.0.1 to 231.39.255.254231.39.255.25565,534
41231.40.0.0/16231.40.0.1 to 231.40.255.254231.40.255.25565,534
42231.41.0.0/16231.41.0.1 to 231.41.255.254231.41.255.25565,534
43231.42.0.0/16231.42.0.1 to 231.42.255.254231.42.255.25565,534
44231.43.0.0/16231.43.0.1 to 231.43.255.254231.43.255.25565,534
45231.44.0.0/16231.44.0.1 to 231.44.255.254231.44.255.25565,534
46231.45.0.0/16231.45.0.1 to 231.45.255.254231.45.255.25565,534
47231.46.0.0/16231.46.0.1 to 231.46.255.254231.46.255.25565,534
48231.47.0.0/16231.47.0.1 to 231.47.255.254231.47.255.25565,534
49231.48.0.0/16231.48.0.1 to 231.48.255.254231.48.255.25565,534
50231.49.0.0/16231.49.0.1 to 231.49.255.254231.49.255.25565,534
51231.50.0.0/16231.50.0.1 to 231.50.255.254231.50.255.25565,534
52231.51.0.0/16231.51.0.1 to 231.51.255.254231.51.255.25565,534
53231.52.0.0/16231.52.0.1 to 231.52.255.254231.52.255.25565,534
54231.53.0.0/16231.53.0.1 to 231.53.255.254231.53.255.25565,534
55231.54.0.0/16231.54.0.1 to 231.54.255.254231.54.255.25565,534
56231.55.0.0/16231.55.0.1 to 231.55.255.254231.55.255.25565,534
57231.56.0.0/16231.56.0.1 to 231.56.255.254231.56.255.25565,534
58231.57.0.0/16231.57.0.1 to 231.57.255.254231.57.255.25565,534
59231.58.0.0/16231.58.0.1 to 231.58.255.254231.58.255.25565,534
60231.59.0.0/16231.59.0.1 to 231.59.255.254231.59.255.25565,534
61231.60.0.0/16231.60.0.1 to 231.60.255.254231.60.255.25565,534
62231.61.0.0/16231.61.0.1 to 231.61.255.254231.61.255.25565,534
63231.62.0.0/16231.62.0.1 to 231.62.255.254231.62.255.25565,534
64231.63.0.0/16231.63.0.1 to 231.63.255.254231.63.255.25565,534
65231.64.0.0/16231.64.0.1 to 231.64.255.254231.64.255.25565,534
66231.65.0.0/16231.65.0.1 to 231.65.255.254231.65.255.25565,534
67231.66.0.0/16231.66.0.1 to 231.66.255.254231.66.255.25565,534
68231.67.0.0/16231.67.0.1 to 231.67.255.254231.67.255.25565,534
69231.68.0.0/16231.68.0.1 to 231.68.255.254231.68.255.25565,534
70231.69.0.0/16231.69.0.1 to 231.69.255.254231.69.255.25565,534
71231.70.0.0/16231.70.0.1 to 231.70.255.254231.70.255.25565,534
72231.71.0.0/16231.71.0.1 to 231.71.255.254231.71.255.25565,534
73231.72.0.0/16231.72.0.1 to 231.72.255.254231.72.255.25565,534
74231.73.0.0/16231.73.0.1 to 231.73.255.254231.73.255.25565,534
75231.74.0.0/16231.74.0.1 to 231.74.255.254231.74.255.25565,534
76231.75.0.0/16231.75.0.1 to 231.75.255.254231.75.255.25565,534
77231.76.0.0/16231.76.0.1 to 231.76.255.254231.76.255.25565,534
78231.77.0.0/16231.77.0.1 to 231.77.255.254231.77.255.25565,534
79231.78.0.0/16231.78.0.1 to 231.78.255.254231.78.255.25565,534
80231.79.0.0/16231.79.0.1 to 231.79.255.254231.79.255.25565,534
81231.80.0.0/16231.80.0.1 to 231.80.255.254231.80.255.25565,534
82231.81.0.0/16231.81.0.1 to 231.81.255.254231.81.255.25565,534
83231.82.0.0/16231.82.0.1 to 231.82.255.254231.82.255.25565,534
84231.83.0.0/16231.83.0.1 to 231.83.255.254231.83.255.25565,534
85231.84.0.0/16231.84.0.1 to 231.84.255.254231.84.255.25565,534
86231.85.0.0/16231.85.0.1 to 231.85.255.254231.85.255.25565,534
87231.86.0.0/16231.86.0.1 to 231.86.255.254231.86.255.25565,534
88231.87.0.0/16231.87.0.1 to 231.87.255.254231.87.255.25565,534
89231.88.0.0/16231.88.0.1 to 231.88.255.254231.88.255.25565,534
90231.89.0.0/16231.89.0.1 to 231.89.255.254231.89.255.25565,534
91231.90.0.0/16231.90.0.1 to 231.90.255.254231.90.255.25565,534
92231.91.0.0/16231.91.0.1 to 231.91.255.254231.91.255.25565,534
93231.92.0.0/16231.92.0.1 to 231.92.255.254231.92.255.25565,534
94231.93.0.0/16231.93.0.1 to 231.93.255.254231.93.255.25565,534
95231.94.0.0/16231.94.0.1 to 231.94.255.254231.94.255.25565,534
96231.95.0.0/16231.95.0.1 to 231.95.255.254231.95.255.25565,534
97231.96.0.0/16231.96.0.1 to 231.96.255.254231.96.255.25565,534
98231.97.0.0/16231.97.0.1 to 231.97.255.254231.97.255.25565,534
99231.98.0.0/16231.98.0.1 to 231.98.255.254231.98.255.25565,534
100231.99.0.0/16231.99.0.1 to 231.99.255.254231.99.255.25565,534
101231.100.0.0/16231.100.0.1 to 231.100.255.254231.100.255.25565,534
102231.101.0.0/16231.101.0.1 to 231.101.255.254231.101.255.25565,534
103231.102.0.0/16231.102.0.1 to 231.102.255.254231.102.255.25565,534
104231.103.0.0/16231.103.0.1 to 231.103.255.254231.103.255.25565,534
105231.104.0.0/16231.104.0.1 to 231.104.255.254231.104.255.25565,534
106231.105.0.0/16231.105.0.1 to 231.105.255.254231.105.255.25565,534
107231.106.0.0/16231.106.0.1 to 231.106.255.254231.106.255.25565,534
108231.107.0.0/16231.107.0.1 to 231.107.255.254231.107.255.25565,534
109231.108.0.0/16231.108.0.1 to 231.108.255.254231.108.255.25565,534
110231.109.0.0/16231.109.0.1 to 231.109.255.254231.109.255.25565,534
111231.110.0.0/16231.110.0.1 to 231.110.255.254231.110.255.25565,534
112231.111.0.0/16231.111.0.1 to 231.111.255.254231.111.255.25565,534
113231.112.0.0/16231.112.0.1 to 231.112.255.254231.112.255.25565,534
114231.113.0.0/16231.113.0.1 to 231.113.255.254231.113.255.25565,534
115231.114.0.0/16231.114.0.1 to 231.114.255.254231.114.255.25565,534
116231.115.0.0/16231.115.0.1 to 231.115.255.254231.115.255.25565,534
117231.116.0.0/16231.116.0.1 to 231.116.255.254231.116.255.25565,534
118231.117.0.0/16231.117.0.1 to 231.117.255.254231.117.255.25565,534
119231.118.0.0/16231.118.0.1 to 231.118.255.254231.118.255.25565,534
120231.119.0.0/16231.119.0.1 to 231.119.255.254231.119.255.25565,534
121231.120.0.0/16231.120.0.1 to 231.120.255.254231.120.255.25565,534
122231.121.0.0/16231.121.0.1 to 231.121.255.254231.121.255.25565,534
123231.122.0.0/16231.122.0.1 to 231.122.255.254231.122.255.25565,534
124231.123.0.0/16231.123.0.1 to 231.123.255.254231.123.255.25565,534
125231.124.0.0/16231.124.0.1 to 231.124.255.254231.124.255.25565,534
126231.125.0.0/16231.125.0.1 to 231.125.255.254231.125.255.25565,534
127231.126.0.0/16231.126.0.1 to 231.126.255.254231.126.255.25565,534
128231.127.0.0/16231.127.0.1 to 231.127.255.254231.127.255.25565,534
129231.128.0.0/16231.128.0.1 to 231.128.255.254231.128.255.25565,534
130231.129.0.0/16231.129.0.1 to 231.129.255.254231.129.255.25565,534
131231.130.0.0/16231.130.0.1 to 231.130.255.254231.130.255.25565,534
132231.131.0.0/16231.131.0.1 to 231.131.255.254231.131.255.25565,534
133231.132.0.0/16231.132.0.1 to 231.132.255.254231.132.255.25565,534
134231.133.0.0/16231.133.0.1 to 231.133.255.254231.133.255.25565,534
135231.134.0.0/16231.134.0.1 to 231.134.255.254231.134.255.25565,534
136231.135.0.0/16231.135.0.1 to 231.135.255.254231.135.255.25565,534
137231.136.0.0/16231.136.0.1 to 231.136.255.254231.136.255.25565,534
138231.137.0.0/16231.137.0.1 to 231.137.255.254231.137.255.25565,534
139231.138.0.0/16231.138.0.1 to 231.138.255.254231.138.255.25565,534
140231.139.0.0/16231.139.0.1 to 231.139.255.254231.139.255.25565,534
141231.140.0.0/16231.140.0.1 to 231.140.255.254231.140.255.25565,534
142231.141.0.0/16231.141.0.1 to 231.141.255.254231.141.255.25565,534
143231.142.0.0/16231.142.0.1 to 231.142.255.254231.142.255.25565,534
144231.143.0.0/16231.143.0.1 to 231.143.255.254231.143.255.25565,534
145231.144.0.0/16231.144.0.1 to 231.144.255.254231.144.255.25565,534
146231.145.0.0/16231.145.0.1 to 231.145.255.254231.145.255.25565,534
147231.146.0.0/16231.146.0.1 to 231.146.255.254231.146.255.25565,534
148231.147.0.0/16231.147.0.1 to 231.147.255.254231.147.255.25565,534
149231.148.0.0/16231.148.0.1 to 231.148.255.254231.148.255.25565,534
150231.149.0.0/16231.149.0.1 to 231.149.255.254231.149.255.25565,534
151231.150.0.0/16231.150.0.1 to 231.150.255.254231.150.255.25565,534
152231.151.0.0/16231.151.0.1 to 231.151.255.254231.151.255.25565,534
153231.152.0.0/16231.152.0.1 to 231.152.255.254231.152.255.25565,534
154231.153.0.0/16231.153.0.1 to 231.153.255.254231.153.255.25565,534
155231.154.0.0/16231.154.0.1 to 231.154.255.254231.154.255.25565,534
156231.155.0.0/16231.155.0.1 to 231.155.255.254231.155.255.25565,534
157231.156.0.0/16231.156.0.1 to 231.156.255.254231.156.255.25565,534
158231.157.0.0/16231.157.0.1 to 231.157.255.254231.157.255.25565,534
159231.158.0.0/16231.158.0.1 to 231.158.255.254231.158.255.25565,534
160231.159.0.0/16231.159.0.1 to 231.159.255.254231.159.255.25565,534
161231.160.0.0/16231.160.0.1 to 231.160.255.254231.160.255.25565,534
162231.161.0.0/16231.161.0.1 to 231.161.255.254231.161.255.25565,534
163231.162.0.0/16231.162.0.1 to 231.162.255.254231.162.255.25565,534
164231.163.0.0/16231.163.0.1 to 231.163.255.254231.163.255.25565,534
165231.164.0.0/16231.164.0.1 to 231.164.255.254231.164.255.25565,534
166231.165.0.0/16231.165.0.1 to 231.165.255.254231.165.255.25565,534
167231.166.0.0/16231.166.0.1 to 231.166.255.254231.166.255.25565,534
168231.167.0.0/16231.167.0.1 to 231.167.255.254231.167.255.25565,534
169231.168.0.0/16231.168.0.1 to 231.168.255.254231.168.255.25565,534
170231.169.0.0/16231.169.0.1 to 231.169.255.254231.169.255.25565,534
171231.170.0.0/16231.170.0.1 to 231.170.255.254231.170.255.25565,534
172231.171.0.0/16231.171.0.1 to 231.171.255.254231.171.255.25565,534
173231.172.0.0/16231.172.0.1 to 231.172.255.254231.172.255.25565,534
174231.173.0.0/16231.173.0.1 to 231.173.255.254231.173.255.25565,534
175231.174.0.0/16231.174.0.1 to 231.174.255.254231.174.255.25565,534
176231.175.0.0/16231.175.0.1 to 231.175.255.254231.175.255.25565,534
177231.176.0.0/16231.176.0.1 to 231.176.255.254231.176.255.25565,534
178231.177.0.0/16231.177.0.1 to 231.177.255.254231.177.255.25565,534
179231.178.0.0/16231.178.0.1 to 231.178.255.254231.178.255.25565,534
180231.179.0.0/16231.179.0.1 to 231.179.255.254231.179.255.25565,534
181231.180.0.0/16231.180.0.1 to 231.180.255.254231.180.255.25565,534
182231.181.0.0/16231.181.0.1 to 231.181.255.254231.181.255.25565,534
183231.182.0.0/16231.182.0.1 to 231.182.255.254231.182.255.25565,534
184231.183.0.0/16231.183.0.1 to 231.183.255.254231.183.255.25565,534
185231.184.0.0/16231.184.0.1 to 231.184.255.254231.184.255.25565,534
186231.185.0.0/16231.185.0.1 to 231.185.255.254231.185.255.25565,534
187231.186.0.0/16231.186.0.1 to 231.186.255.254231.186.255.25565,534
188231.187.0.0/16231.187.0.1 to 231.187.255.254231.187.255.25565,534
189231.188.0.0/16231.188.0.1 to 231.188.255.254231.188.255.25565,534
190231.189.0.0/16231.189.0.1 to 231.189.255.254231.189.255.25565,534
191231.190.0.0/16231.190.0.1 to 231.190.255.254231.190.255.25565,534
192231.191.0.0/16231.191.0.1 to 231.191.255.254231.191.255.25565,534
193231.192.0.0/16231.192.0.1 to 231.192.255.254231.192.255.25565,534
194231.193.0.0/16231.193.0.1 to 231.193.255.254231.193.255.25565,534
195231.194.0.0/16231.194.0.1 to 231.194.255.254231.194.255.25565,534
196231.195.0.0/16231.195.0.1 to 231.195.255.254231.195.255.25565,534
197231.196.0.0/16231.196.0.1 to 231.196.255.254231.196.255.25565,534
198231.197.0.0/16231.197.0.1 to 231.197.255.254231.197.255.25565,534
199231.198.0.0/16231.198.0.1 to 231.198.255.254231.198.255.25565,534
200231.199.0.0/16231.199.0.1 to 231.199.255.254231.199.255.25565,534
201231.200.0.0/16231.200.0.1 to 231.200.255.254231.200.255.25565,534
202231.201.0.0/16231.201.0.1 to 231.201.255.254231.201.255.25565,534
203231.202.0.0/16231.202.0.1 to 231.202.255.254231.202.255.25565,534
204231.203.0.0/16231.203.0.1 to 231.203.255.254231.203.255.25565,534
205231.204.0.0/16231.204.0.1 to 231.204.255.254231.204.255.25565,534
206231.205.0.0/16231.205.0.1 to 231.205.255.254231.205.255.25565,534
207231.206.0.0/16231.206.0.1 to 231.206.255.254231.206.255.25565,534
208231.207.0.0/16231.207.0.1 to 231.207.255.254231.207.255.25565,534
209231.208.0.0/16231.208.0.1 to 231.208.255.254231.208.255.25565,534
210231.209.0.0/16231.209.0.1 to 231.209.255.254231.209.255.25565,534
211231.210.0.0/16231.210.0.1 to 231.210.255.254231.210.255.25565,534
212231.211.0.0/16231.211.0.1 to 231.211.255.254231.211.255.25565,534
213231.212.0.0/16231.212.0.1 to 231.212.255.254231.212.255.25565,534
214231.213.0.0/16231.213.0.1 to 231.213.255.254231.213.255.25565,534
215231.214.0.0/16231.214.0.1 to 231.214.255.254231.214.255.25565,534
216231.215.0.0/16231.215.0.1 to 231.215.255.254231.215.255.25565,534
217231.216.0.0/16231.216.0.1 to 231.216.255.254231.216.255.25565,534
218231.217.0.0/16231.217.0.1 to 231.217.255.254231.217.255.25565,534
219231.218.0.0/16231.218.0.1 to 231.218.255.254231.218.255.25565,534
220231.219.0.0/16231.219.0.1 to 231.219.255.254231.219.255.25565,534
221231.220.0.0/16231.220.0.1 to 231.220.255.254231.220.255.25565,534
222231.221.0.0/16231.221.0.1 to 231.221.255.254231.221.255.25565,534
223231.222.0.0/16231.222.0.1 to 231.222.255.254231.222.255.25565,534
224231.223.0.0/16231.223.0.1 to 231.223.255.254231.223.255.25565,534
225231.224.0.0/16231.224.0.1 to 231.224.255.254231.224.255.25565,534
226231.225.0.0/16231.225.0.1 to 231.225.255.254231.225.255.25565,534
227231.226.0.0/16231.226.0.1 to 231.226.255.254231.226.255.25565,534
228231.227.0.0/16231.227.0.1 to 231.227.255.254231.227.255.25565,534
229231.228.0.0/16231.228.0.1 to 231.228.255.254231.228.255.25565,534
230231.229.0.0/16231.229.0.1 to 231.229.255.254231.229.255.25565,534
231231.230.0.0/16231.230.0.1 to 231.230.255.254231.230.255.25565,534
232231.231.0.0/16231.231.0.1 to 231.231.255.254231.231.255.25565,534
233231.232.0.0/16231.232.0.1 to 231.232.255.254231.232.255.25565,534
234231.233.0.0/16231.233.0.1 to 231.233.255.254231.233.255.25565,534
235231.234.0.0/16231.234.0.1 to 231.234.255.254231.234.255.25565,534
236231.235.0.0/16231.235.0.1 to 231.235.255.254231.235.255.25565,534
237231.236.0.0/16231.236.0.1 to 231.236.255.254231.236.255.25565,534
238231.237.0.0/16231.237.0.1 to 231.237.255.254231.237.255.25565,534
239231.238.0.0/16231.238.0.1 to 231.238.255.254231.238.255.25565,534
240231.239.0.0/16231.239.0.1 to 231.239.255.254231.239.255.25565,534
241231.240.0.0/16231.240.0.1 to 231.240.255.254231.240.255.25565,534
242231.241.0.0/16231.241.0.1 to 231.241.255.254231.241.255.25565,534
243231.242.0.0/16231.242.0.1 to 231.242.255.254231.242.255.25565,534
244231.243.0.0/16231.243.0.1 to 231.243.255.254231.243.255.25565,534
245231.244.0.0/16231.244.0.1 to 231.244.255.254231.244.255.25565,534
246231.245.0.0/16231.245.0.1 to 231.245.255.254231.245.255.25565,534
247231.246.0.0/16231.246.0.1 to 231.246.255.254231.246.255.25565,534
248231.247.0.0/16231.247.0.1 to 231.247.255.254231.247.255.25565,534
249231.248.0.0/16231.248.0.1 to 231.248.255.254231.248.255.25565,534
250231.249.0.0/16231.249.0.1 to 231.249.255.254231.249.255.25565,534
251231.250.0.0/16231.250.0.1 to 231.250.255.254231.250.255.25565,534
252231.251.0.0/16231.251.0.1 to 231.251.255.254231.251.255.25565,534
253231.252.0.0/16231.252.0.1 to 231.252.255.254231.252.255.25565,534
254231.253.0.0/16231.253.0.1 to 231.253.255.254231.253.255.25565,534
255231.254.0.0/16231.254.0.1 to 231.254.255.254231.254.255.25565,534
256231.255.0.0/16231.255.0.1 to 231.255.255.254231.255.255.25565,534

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.