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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.

Network161.78.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
161.78.0.0
Broadcast address
161.79.255.255
First usable
161.78.0.1
Last usable
161.79.255.254
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
Public public
Old class
B (default /16)
As numbers
Hex A14E0000 · Integer 2706243584 to 2706374655
Reverse DNS zones
78.161.in-addr.arpa
79.161.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
Address10100001.01001110.00000000.00000000161.78.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network10100001.01001110.00000000.00000000161.78.0.0
Broadcast10100001.01001111.11111111.11111111161.79.255.255
Split into smaller subnets/24
/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)

161.78.0.0/15 makes 512 subnets of /24; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1161.78.0.0/24161.78.0.1 to 161.78.0.254161.78.0.255254
2161.78.1.0/24161.78.1.1 to 161.78.1.254161.78.1.255254
3161.78.2.0/24161.78.2.1 to 161.78.2.254161.78.2.255254
4161.78.3.0/24161.78.3.1 to 161.78.3.254161.78.3.255254
5161.78.4.0/24161.78.4.1 to 161.78.4.254161.78.4.255254
6161.78.5.0/24161.78.5.1 to 161.78.5.254161.78.5.255254
7161.78.6.0/24161.78.6.1 to 161.78.6.254161.78.6.255254
8161.78.7.0/24161.78.7.1 to 161.78.7.254161.78.7.255254
9161.78.8.0/24161.78.8.1 to 161.78.8.254161.78.8.255254
10161.78.9.0/24161.78.9.1 to 161.78.9.254161.78.9.255254
11161.78.10.0/24161.78.10.1 to 161.78.10.254161.78.10.255254
12161.78.11.0/24161.78.11.1 to 161.78.11.254161.78.11.255254
13161.78.12.0/24161.78.12.1 to 161.78.12.254161.78.12.255254
14161.78.13.0/24161.78.13.1 to 161.78.13.254161.78.13.255254
15161.78.14.0/24161.78.14.1 to 161.78.14.254161.78.14.255254
16161.78.15.0/24161.78.15.1 to 161.78.15.254161.78.15.255254
17161.78.16.0/24161.78.16.1 to 161.78.16.254161.78.16.255254
18161.78.17.0/24161.78.17.1 to 161.78.17.254161.78.17.255254
19161.78.18.0/24161.78.18.1 to 161.78.18.254161.78.18.255254
20161.78.19.0/24161.78.19.1 to 161.78.19.254161.78.19.255254
21161.78.20.0/24161.78.20.1 to 161.78.20.254161.78.20.255254
22161.78.21.0/24161.78.21.1 to 161.78.21.254161.78.21.255254
23161.78.22.0/24161.78.22.1 to 161.78.22.254161.78.22.255254
24161.78.23.0/24161.78.23.1 to 161.78.23.254161.78.23.255254
25161.78.24.0/24161.78.24.1 to 161.78.24.254161.78.24.255254
26161.78.25.0/24161.78.25.1 to 161.78.25.254161.78.25.255254
27161.78.26.0/24161.78.26.1 to 161.78.26.254161.78.26.255254
28161.78.27.0/24161.78.27.1 to 161.78.27.254161.78.27.255254
29161.78.28.0/24161.78.28.1 to 161.78.28.254161.78.28.255254
30161.78.29.0/24161.78.29.1 to 161.78.29.254161.78.29.255254
31161.78.30.0/24161.78.30.1 to 161.78.30.254161.78.30.255254
32161.78.31.0/24161.78.31.1 to 161.78.31.254161.78.31.255254
33161.78.32.0/24161.78.32.1 to 161.78.32.254161.78.32.255254
34161.78.33.0/24161.78.33.1 to 161.78.33.254161.78.33.255254
35161.78.34.0/24161.78.34.1 to 161.78.34.254161.78.34.255254
36161.78.35.0/24161.78.35.1 to 161.78.35.254161.78.35.255254
37161.78.36.0/24161.78.36.1 to 161.78.36.254161.78.36.255254
38161.78.37.0/24161.78.37.1 to 161.78.37.254161.78.37.255254
39161.78.38.0/24161.78.38.1 to 161.78.38.254161.78.38.255254
40161.78.39.0/24161.78.39.1 to 161.78.39.254161.78.39.255254
41161.78.40.0/24161.78.40.1 to 161.78.40.254161.78.40.255254
42161.78.41.0/24161.78.41.1 to 161.78.41.254161.78.41.255254
43161.78.42.0/24161.78.42.1 to 161.78.42.254161.78.42.255254
44161.78.43.0/24161.78.43.1 to 161.78.43.254161.78.43.255254
45161.78.44.0/24161.78.44.1 to 161.78.44.254161.78.44.255254
46161.78.45.0/24161.78.45.1 to 161.78.45.254161.78.45.255254
47161.78.46.0/24161.78.46.1 to 161.78.46.254161.78.46.255254
48161.78.47.0/24161.78.47.1 to 161.78.47.254161.78.47.255254
49161.78.48.0/24161.78.48.1 to 161.78.48.254161.78.48.255254
50161.78.49.0/24161.78.49.1 to 161.78.49.254161.78.49.255254
51161.78.50.0/24161.78.50.1 to 161.78.50.254161.78.50.255254
52161.78.51.0/24161.78.51.1 to 161.78.51.254161.78.51.255254
53161.78.52.0/24161.78.52.1 to 161.78.52.254161.78.52.255254
54161.78.53.0/24161.78.53.1 to 161.78.53.254161.78.53.255254
55161.78.54.0/24161.78.54.1 to 161.78.54.254161.78.54.255254
56161.78.55.0/24161.78.55.1 to 161.78.55.254161.78.55.255254
57161.78.56.0/24161.78.56.1 to 161.78.56.254161.78.56.255254
58161.78.57.0/24161.78.57.1 to 161.78.57.254161.78.57.255254
59161.78.58.0/24161.78.58.1 to 161.78.58.254161.78.58.255254
60161.78.59.0/24161.78.59.1 to 161.78.59.254161.78.59.255254
61161.78.60.0/24161.78.60.1 to 161.78.60.254161.78.60.255254
62161.78.61.0/24161.78.61.1 to 161.78.61.254161.78.61.255254
63161.78.62.0/24161.78.62.1 to 161.78.62.254161.78.62.255254
64161.78.63.0/24161.78.63.1 to 161.78.63.254161.78.63.255254
65161.78.64.0/24161.78.64.1 to 161.78.64.254161.78.64.255254
66161.78.65.0/24161.78.65.1 to 161.78.65.254161.78.65.255254
67161.78.66.0/24161.78.66.1 to 161.78.66.254161.78.66.255254
68161.78.67.0/24161.78.67.1 to 161.78.67.254161.78.67.255254
69161.78.68.0/24161.78.68.1 to 161.78.68.254161.78.68.255254
70161.78.69.0/24161.78.69.1 to 161.78.69.254161.78.69.255254
71161.78.70.0/24161.78.70.1 to 161.78.70.254161.78.70.255254
72161.78.71.0/24161.78.71.1 to 161.78.71.254161.78.71.255254
73161.78.72.0/24161.78.72.1 to 161.78.72.254161.78.72.255254
74161.78.73.0/24161.78.73.1 to 161.78.73.254161.78.73.255254
75161.78.74.0/24161.78.74.1 to 161.78.74.254161.78.74.255254
76161.78.75.0/24161.78.75.1 to 161.78.75.254161.78.75.255254
77161.78.76.0/24161.78.76.1 to 161.78.76.254161.78.76.255254
78161.78.77.0/24161.78.77.1 to 161.78.77.254161.78.77.255254
79161.78.78.0/24161.78.78.1 to 161.78.78.254161.78.78.255254
80161.78.79.0/24161.78.79.1 to 161.78.79.254161.78.79.255254
81161.78.80.0/24161.78.80.1 to 161.78.80.254161.78.80.255254
82161.78.81.0/24161.78.81.1 to 161.78.81.254161.78.81.255254
83161.78.82.0/24161.78.82.1 to 161.78.82.254161.78.82.255254
84161.78.83.0/24161.78.83.1 to 161.78.83.254161.78.83.255254
85161.78.84.0/24161.78.84.1 to 161.78.84.254161.78.84.255254
86161.78.85.0/24161.78.85.1 to 161.78.85.254161.78.85.255254
87161.78.86.0/24161.78.86.1 to 161.78.86.254161.78.86.255254
88161.78.87.0/24161.78.87.1 to 161.78.87.254161.78.87.255254
89161.78.88.0/24161.78.88.1 to 161.78.88.254161.78.88.255254
90161.78.89.0/24161.78.89.1 to 161.78.89.254161.78.89.255254
91161.78.90.0/24161.78.90.1 to 161.78.90.254161.78.90.255254
92161.78.91.0/24161.78.91.1 to 161.78.91.254161.78.91.255254
93161.78.92.0/24161.78.92.1 to 161.78.92.254161.78.92.255254
94161.78.93.0/24161.78.93.1 to 161.78.93.254161.78.93.255254
95161.78.94.0/24161.78.94.1 to 161.78.94.254161.78.94.255254
96161.78.95.0/24161.78.95.1 to 161.78.95.254161.78.95.255254
97161.78.96.0/24161.78.96.1 to 161.78.96.254161.78.96.255254
98161.78.97.0/24161.78.97.1 to 161.78.97.254161.78.97.255254
99161.78.98.0/24161.78.98.1 to 161.78.98.254161.78.98.255254
100161.78.99.0/24161.78.99.1 to 161.78.99.254161.78.99.255254
101161.78.100.0/24161.78.100.1 to 161.78.100.254161.78.100.255254
102161.78.101.0/24161.78.101.1 to 161.78.101.254161.78.101.255254
103161.78.102.0/24161.78.102.1 to 161.78.102.254161.78.102.255254
104161.78.103.0/24161.78.103.1 to 161.78.103.254161.78.103.255254
105161.78.104.0/24161.78.104.1 to 161.78.104.254161.78.104.255254
106161.78.105.0/24161.78.105.1 to 161.78.105.254161.78.105.255254
107161.78.106.0/24161.78.106.1 to 161.78.106.254161.78.106.255254
108161.78.107.0/24161.78.107.1 to 161.78.107.254161.78.107.255254
109161.78.108.0/24161.78.108.1 to 161.78.108.254161.78.108.255254
110161.78.109.0/24161.78.109.1 to 161.78.109.254161.78.109.255254
111161.78.110.0/24161.78.110.1 to 161.78.110.254161.78.110.255254
112161.78.111.0/24161.78.111.1 to 161.78.111.254161.78.111.255254
113161.78.112.0/24161.78.112.1 to 161.78.112.254161.78.112.255254
114161.78.113.0/24161.78.113.1 to 161.78.113.254161.78.113.255254
115161.78.114.0/24161.78.114.1 to 161.78.114.254161.78.114.255254
116161.78.115.0/24161.78.115.1 to 161.78.115.254161.78.115.255254
117161.78.116.0/24161.78.116.1 to 161.78.116.254161.78.116.255254
118161.78.117.0/24161.78.117.1 to 161.78.117.254161.78.117.255254
119161.78.118.0/24161.78.118.1 to 161.78.118.254161.78.118.255254
120161.78.119.0/24161.78.119.1 to 161.78.119.254161.78.119.255254
121161.78.120.0/24161.78.120.1 to 161.78.120.254161.78.120.255254
122161.78.121.0/24161.78.121.1 to 161.78.121.254161.78.121.255254
123161.78.122.0/24161.78.122.1 to 161.78.122.254161.78.122.255254
124161.78.123.0/24161.78.123.1 to 161.78.123.254161.78.123.255254
125161.78.124.0/24161.78.124.1 to 161.78.124.254161.78.124.255254
126161.78.125.0/24161.78.125.1 to 161.78.125.254161.78.125.255254
127161.78.126.0/24161.78.126.1 to 161.78.126.254161.78.126.255254
128161.78.127.0/24161.78.127.1 to 161.78.127.254161.78.127.255254
129161.78.128.0/24161.78.128.1 to 161.78.128.254161.78.128.255254
130161.78.129.0/24161.78.129.1 to 161.78.129.254161.78.129.255254
131161.78.130.0/24161.78.130.1 to 161.78.130.254161.78.130.255254
132161.78.131.0/24161.78.131.1 to 161.78.131.254161.78.131.255254
133161.78.132.0/24161.78.132.1 to 161.78.132.254161.78.132.255254
134161.78.133.0/24161.78.133.1 to 161.78.133.254161.78.133.255254
135161.78.134.0/24161.78.134.1 to 161.78.134.254161.78.134.255254
136161.78.135.0/24161.78.135.1 to 161.78.135.254161.78.135.255254
137161.78.136.0/24161.78.136.1 to 161.78.136.254161.78.136.255254
138161.78.137.0/24161.78.137.1 to 161.78.137.254161.78.137.255254
139161.78.138.0/24161.78.138.1 to 161.78.138.254161.78.138.255254
140161.78.139.0/24161.78.139.1 to 161.78.139.254161.78.139.255254
141161.78.140.0/24161.78.140.1 to 161.78.140.254161.78.140.255254
142161.78.141.0/24161.78.141.1 to 161.78.141.254161.78.141.255254
143161.78.142.0/24161.78.142.1 to 161.78.142.254161.78.142.255254
144161.78.143.0/24161.78.143.1 to 161.78.143.254161.78.143.255254
145161.78.144.0/24161.78.144.1 to 161.78.144.254161.78.144.255254
146161.78.145.0/24161.78.145.1 to 161.78.145.254161.78.145.255254
147161.78.146.0/24161.78.146.1 to 161.78.146.254161.78.146.255254
148161.78.147.0/24161.78.147.1 to 161.78.147.254161.78.147.255254
149161.78.148.0/24161.78.148.1 to 161.78.148.254161.78.148.255254
150161.78.149.0/24161.78.149.1 to 161.78.149.254161.78.149.255254
151161.78.150.0/24161.78.150.1 to 161.78.150.254161.78.150.255254
152161.78.151.0/24161.78.151.1 to 161.78.151.254161.78.151.255254
153161.78.152.0/24161.78.152.1 to 161.78.152.254161.78.152.255254
154161.78.153.0/24161.78.153.1 to 161.78.153.254161.78.153.255254
155161.78.154.0/24161.78.154.1 to 161.78.154.254161.78.154.255254
156161.78.155.0/24161.78.155.1 to 161.78.155.254161.78.155.255254
157161.78.156.0/24161.78.156.1 to 161.78.156.254161.78.156.255254
158161.78.157.0/24161.78.157.1 to 161.78.157.254161.78.157.255254
159161.78.158.0/24161.78.158.1 to 161.78.158.254161.78.158.255254
160161.78.159.0/24161.78.159.1 to 161.78.159.254161.78.159.255254
161161.78.160.0/24161.78.160.1 to 161.78.160.254161.78.160.255254
162161.78.161.0/24161.78.161.1 to 161.78.161.254161.78.161.255254
163161.78.162.0/24161.78.162.1 to 161.78.162.254161.78.162.255254
164161.78.163.0/24161.78.163.1 to 161.78.163.254161.78.163.255254
165161.78.164.0/24161.78.164.1 to 161.78.164.254161.78.164.255254
166161.78.165.0/24161.78.165.1 to 161.78.165.254161.78.165.255254
167161.78.166.0/24161.78.166.1 to 161.78.166.254161.78.166.255254
168161.78.167.0/24161.78.167.1 to 161.78.167.254161.78.167.255254
169161.78.168.0/24161.78.168.1 to 161.78.168.254161.78.168.255254
170161.78.169.0/24161.78.169.1 to 161.78.169.254161.78.169.255254
171161.78.170.0/24161.78.170.1 to 161.78.170.254161.78.170.255254
172161.78.171.0/24161.78.171.1 to 161.78.171.254161.78.171.255254
173161.78.172.0/24161.78.172.1 to 161.78.172.254161.78.172.255254
174161.78.173.0/24161.78.173.1 to 161.78.173.254161.78.173.255254
175161.78.174.0/24161.78.174.1 to 161.78.174.254161.78.174.255254
176161.78.175.0/24161.78.175.1 to 161.78.175.254161.78.175.255254
177161.78.176.0/24161.78.176.1 to 161.78.176.254161.78.176.255254
178161.78.177.0/24161.78.177.1 to 161.78.177.254161.78.177.255254
179161.78.178.0/24161.78.178.1 to 161.78.178.254161.78.178.255254
180161.78.179.0/24161.78.179.1 to 161.78.179.254161.78.179.255254
181161.78.180.0/24161.78.180.1 to 161.78.180.254161.78.180.255254
182161.78.181.0/24161.78.181.1 to 161.78.181.254161.78.181.255254
183161.78.182.0/24161.78.182.1 to 161.78.182.254161.78.182.255254
184161.78.183.0/24161.78.183.1 to 161.78.183.254161.78.183.255254
185161.78.184.0/24161.78.184.1 to 161.78.184.254161.78.184.255254
186161.78.185.0/24161.78.185.1 to 161.78.185.254161.78.185.255254
187161.78.186.0/24161.78.186.1 to 161.78.186.254161.78.186.255254
188161.78.187.0/24161.78.187.1 to 161.78.187.254161.78.187.255254
189161.78.188.0/24161.78.188.1 to 161.78.188.254161.78.188.255254
190161.78.189.0/24161.78.189.1 to 161.78.189.254161.78.189.255254
191161.78.190.0/24161.78.190.1 to 161.78.190.254161.78.190.255254
192161.78.191.0/24161.78.191.1 to 161.78.191.254161.78.191.255254
193161.78.192.0/24161.78.192.1 to 161.78.192.254161.78.192.255254
194161.78.193.0/24161.78.193.1 to 161.78.193.254161.78.193.255254
195161.78.194.0/24161.78.194.1 to 161.78.194.254161.78.194.255254
196161.78.195.0/24161.78.195.1 to 161.78.195.254161.78.195.255254
197161.78.196.0/24161.78.196.1 to 161.78.196.254161.78.196.255254
198161.78.197.0/24161.78.197.1 to 161.78.197.254161.78.197.255254
199161.78.198.0/24161.78.198.1 to 161.78.198.254161.78.198.255254
200161.78.199.0/24161.78.199.1 to 161.78.199.254161.78.199.255254
201161.78.200.0/24161.78.200.1 to 161.78.200.254161.78.200.255254
202161.78.201.0/24161.78.201.1 to 161.78.201.254161.78.201.255254
203161.78.202.0/24161.78.202.1 to 161.78.202.254161.78.202.255254
204161.78.203.0/24161.78.203.1 to 161.78.203.254161.78.203.255254
205161.78.204.0/24161.78.204.1 to 161.78.204.254161.78.204.255254
206161.78.205.0/24161.78.205.1 to 161.78.205.254161.78.205.255254
207161.78.206.0/24161.78.206.1 to 161.78.206.254161.78.206.255254
208161.78.207.0/24161.78.207.1 to 161.78.207.254161.78.207.255254
209161.78.208.0/24161.78.208.1 to 161.78.208.254161.78.208.255254
210161.78.209.0/24161.78.209.1 to 161.78.209.254161.78.209.255254
211161.78.210.0/24161.78.210.1 to 161.78.210.254161.78.210.255254
212161.78.211.0/24161.78.211.1 to 161.78.211.254161.78.211.255254
213161.78.212.0/24161.78.212.1 to 161.78.212.254161.78.212.255254
214161.78.213.0/24161.78.213.1 to 161.78.213.254161.78.213.255254
215161.78.214.0/24161.78.214.1 to 161.78.214.254161.78.214.255254
216161.78.215.0/24161.78.215.1 to 161.78.215.254161.78.215.255254
217161.78.216.0/24161.78.216.1 to 161.78.216.254161.78.216.255254
218161.78.217.0/24161.78.217.1 to 161.78.217.254161.78.217.255254
219161.78.218.0/24161.78.218.1 to 161.78.218.254161.78.218.255254
220161.78.219.0/24161.78.219.1 to 161.78.219.254161.78.219.255254
221161.78.220.0/24161.78.220.1 to 161.78.220.254161.78.220.255254
222161.78.221.0/24161.78.221.1 to 161.78.221.254161.78.221.255254
223161.78.222.0/24161.78.222.1 to 161.78.222.254161.78.222.255254
224161.78.223.0/24161.78.223.1 to 161.78.223.254161.78.223.255254
225161.78.224.0/24161.78.224.1 to 161.78.224.254161.78.224.255254
226161.78.225.0/24161.78.225.1 to 161.78.225.254161.78.225.255254
227161.78.226.0/24161.78.226.1 to 161.78.226.254161.78.226.255254
228161.78.227.0/24161.78.227.1 to 161.78.227.254161.78.227.255254
229161.78.228.0/24161.78.228.1 to 161.78.228.254161.78.228.255254
230161.78.229.0/24161.78.229.1 to 161.78.229.254161.78.229.255254
231161.78.230.0/24161.78.230.1 to 161.78.230.254161.78.230.255254
232161.78.231.0/24161.78.231.1 to 161.78.231.254161.78.231.255254
233161.78.232.0/24161.78.232.1 to 161.78.232.254161.78.232.255254
234161.78.233.0/24161.78.233.1 to 161.78.233.254161.78.233.255254
235161.78.234.0/24161.78.234.1 to 161.78.234.254161.78.234.255254
236161.78.235.0/24161.78.235.1 to 161.78.235.254161.78.235.255254
237161.78.236.0/24161.78.236.1 to 161.78.236.254161.78.236.255254
238161.78.237.0/24161.78.237.1 to 161.78.237.254161.78.237.255254
239161.78.238.0/24161.78.238.1 to 161.78.238.254161.78.238.255254
240161.78.239.0/24161.78.239.1 to 161.78.239.254161.78.239.255254
241161.78.240.0/24161.78.240.1 to 161.78.240.254161.78.240.255254
242161.78.241.0/24161.78.241.1 to 161.78.241.254161.78.241.255254
243161.78.242.0/24161.78.242.1 to 161.78.242.254161.78.242.255254
244161.78.243.0/24161.78.243.1 to 161.78.243.254161.78.243.255254
245161.78.244.0/24161.78.244.1 to 161.78.244.254161.78.244.255254
246161.78.245.0/24161.78.245.1 to 161.78.245.254161.78.245.255254
247161.78.246.0/24161.78.246.1 to 161.78.246.254161.78.246.255254
248161.78.247.0/24161.78.247.1 to 161.78.247.254161.78.247.255254
249161.78.248.0/24161.78.248.1 to 161.78.248.254161.78.248.255254
250161.78.249.0/24161.78.249.1 to 161.78.249.254161.78.249.255254
251161.78.250.0/24161.78.250.1 to 161.78.250.254161.78.250.255254
252161.78.251.0/24161.78.251.1 to 161.78.251.254161.78.251.255254
253161.78.252.0/24161.78.252.1 to 161.78.252.254161.78.252.255254
254161.78.253.0/24161.78.253.1 to 161.78.253.254161.78.253.255254
255161.78.254.0/24161.78.254.1 to 161.78.254.254161.78.254.255254
256161.78.255.0/24161.78.255.1 to 161.78.255.254161.78.255.255254

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.