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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.

Network185.4.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
185.4.0.0
Broadcast address
185.4.255.255
First usable
185.4.0.1
Last usable
185.4.255.254
Usable hosts
65,534 (65,536 less the network and broadcast addresses)
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255 (Cisco ACLs, OSPF)
Prefix length
/16
Type
Public public
Old class
B (default /16)
As numbers
Hex B9040000 · Integer 3104047104 to 3104112639
Reverse DNS zone
4.185.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10111001.00000100..00000000.00000000185.4.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network10111001.00000100..00000000.00000000185.4.0.0
Broadcast10111001.00000100..11111111.11111111185.4.255.255
Split into smaller subnets/24
/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

185.4.0.0/16 makes 256 subnets of /24.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1185.4.0.0/24185.4.0.1 to 185.4.0.254185.4.0.255254
2185.4.1.0/24185.4.1.1 to 185.4.1.254185.4.1.255254
3185.4.2.0/24185.4.2.1 to 185.4.2.254185.4.2.255254
4185.4.3.0/24185.4.3.1 to 185.4.3.254185.4.3.255254
5185.4.4.0/24185.4.4.1 to 185.4.4.254185.4.4.255254
6185.4.5.0/24185.4.5.1 to 185.4.5.254185.4.5.255254
7185.4.6.0/24185.4.6.1 to 185.4.6.254185.4.6.255254
8185.4.7.0/24185.4.7.1 to 185.4.7.254185.4.7.255254
9185.4.8.0/24185.4.8.1 to 185.4.8.254185.4.8.255254
10185.4.9.0/24185.4.9.1 to 185.4.9.254185.4.9.255254
11185.4.10.0/24185.4.10.1 to 185.4.10.254185.4.10.255254
12185.4.11.0/24185.4.11.1 to 185.4.11.254185.4.11.255254
13185.4.12.0/24185.4.12.1 to 185.4.12.254185.4.12.255254
14185.4.13.0/24185.4.13.1 to 185.4.13.254185.4.13.255254
15185.4.14.0/24185.4.14.1 to 185.4.14.254185.4.14.255254
16185.4.15.0/24185.4.15.1 to 185.4.15.254185.4.15.255254
17185.4.16.0/24185.4.16.1 to 185.4.16.254185.4.16.255254
18185.4.17.0/24185.4.17.1 to 185.4.17.254185.4.17.255254
19185.4.18.0/24185.4.18.1 to 185.4.18.254185.4.18.255254
20185.4.19.0/24185.4.19.1 to 185.4.19.254185.4.19.255254
21185.4.20.0/24185.4.20.1 to 185.4.20.254185.4.20.255254
22185.4.21.0/24185.4.21.1 to 185.4.21.254185.4.21.255254
23185.4.22.0/24185.4.22.1 to 185.4.22.254185.4.22.255254
24185.4.23.0/24185.4.23.1 to 185.4.23.254185.4.23.255254
25185.4.24.0/24185.4.24.1 to 185.4.24.254185.4.24.255254
26185.4.25.0/24185.4.25.1 to 185.4.25.254185.4.25.255254
27185.4.26.0/24185.4.26.1 to 185.4.26.254185.4.26.255254
28185.4.27.0/24185.4.27.1 to 185.4.27.254185.4.27.255254
29185.4.28.0/24185.4.28.1 to 185.4.28.254185.4.28.255254
30185.4.29.0/24185.4.29.1 to 185.4.29.254185.4.29.255254
31185.4.30.0/24185.4.30.1 to 185.4.30.254185.4.30.255254
32185.4.31.0/24185.4.31.1 to 185.4.31.254185.4.31.255254
33185.4.32.0/24185.4.32.1 to 185.4.32.254185.4.32.255254
34185.4.33.0/24185.4.33.1 to 185.4.33.254185.4.33.255254
35185.4.34.0/24185.4.34.1 to 185.4.34.254185.4.34.255254
36185.4.35.0/24185.4.35.1 to 185.4.35.254185.4.35.255254
37185.4.36.0/24185.4.36.1 to 185.4.36.254185.4.36.255254
38185.4.37.0/24185.4.37.1 to 185.4.37.254185.4.37.255254
39185.4.38.0/24185.4.38.1 to 185.4.38.254185.4.38.255254
40185.4.39.0/24185.4.39.1 to 185.4.39.254185.4.39.255254
41185.4.40.0/24185.4.40.1 to 185.4.40.254185.4.40.255254
42185.4.41.0/24185.4.41.1 to 185.4.41.254185.4.41.255254
43185.4.42.0/24185.4.42.1 to 185.4.42.254185.4.42.255254
44185.4.43.0/24185.4.43.1 to 185.4.43.254185.4.43.255254
45185.4.44.0/24185.4.44.1 to 185.4.44.254185.4.44.255254
46185.4.45.0/24185.4.45.1 to 185.4.45.254185.4.45.255254
47185.4.46.0/24185.4.46.1 to 185.4.46.254185.4.46.255254
48185.4.47.0/24185.4.47.1 to 185.4.47.254185.4.47.255254
49185.4.48.0/24185.4.48.1 to 185.4.48.254185.4.48.255254
50185.4.49.0/24185.4.49.1 to 185.4.49.254185.4.49.255254
51185.4.50.0/24185.4.50.1 to 185.4.50.254185.4.50.255254
52185.4.51.0/24185.4.51.1 to 185.4.51.254185.4.51.255254
53185.4.52.0/24185.4.52.1 to 185.4.52.254185.4.52.255254
54185.4.53.0/24185.4.53.1 to 185.4.53.254185.4.53.255254
55185.4.54.0/24185.4.54.1 to 185.4.54.254185.4.54.255254
56185.4.55.0/24185.4.55.1 to 185.4.55.254185.4.55.255254
57185.4.56.0/24185.4.56.1 to 185.4.56.254185.4.56.255254
58185.4.57.0/24185.4.57.1 to 185.4.57.254185.4.57.255254
59185.4.58.0/24185.4.58.1 to 185.4.58.254185.4.58.255254
60185.4.59.0/24185.4.59.1 to 185.4.59.254185.4.59.255254
61185.4.60.0/24185.4.60.1 to 185.4.60.254185.4.60.255254
62185.4.61.0/24185.4.61.1 to 185.4.61.254185.4.61.255254
63185.4.62.0/24185.4.62.1 to 185.4.62.254185.4.62.255254
64185.4.63.0/24185.4.63.1 to 185.4.63.254185.4.63.255254
65185.4.64.0/24185.4.64.1 to 185.4.64.254185.4.64.255254
66185.4.65.0/24185.4.65.1 to 185.4.65.254185.4.65.255254
67185.4.66.0/24185.4.66.1 to 185.4.66.254185.4.66.255254
68185.4.67.0/24185.4.67.1 to 185.4.67.254185.4.67.255254
69185.4.68.0/24185.4.68.1 to 185.4.68.254185.4.68.255254
70185.4.69.0/24185.4.69.1 to 185.4.69.254185.4.69.255254
71185.4.70.0/24185.4.70.1 to 185.4.70.254185.4.70.255254
72185.4.71.0/24185.4.71.1 to 185.4.71.254185.4.71.255254
73185.4.72.0/24185.4.72.1 to 185.4.72.254185.4.72.255254
74185.4.73.0/24185.4.73.1 to 185.4.73.254185.4.73.255254
75185.4.74.0/24185.4.74.1 to 185.4.74.254185.4.74.255254
76185.4.75.0/24185.4.75.1 to 185.4.75.254185.4.75.255254
77185.4.76.0/24185.4.76.1 to 185.4.76.254185.4.76.255254
78185.4.77.0/24185.4.77.1 to 185.4.77.254185.4.77.255254
79185.4.78.0/24185.4.78.1 to 185.4.78.254185.4.78.255254
80185.4.79.0/24185.4.79.1 to 185.4.79.254185.4.79.255254
81185.4.80.0/24185.4.80.1 to 185.4.80.254185.4.80.255254
82185.4.81.0/24185.4.81.1 to 185.4.81.254185.4.81.255254
83185.4.82.0/24185.4.82.1 to 185.4.82.254185.4.82.255254
84185.4.83.0/24185.4.83.1 to 185.4.83.254185.4.83.255254
85185.4.84.0/24185.4.84.1 to 185.4.84.254185.4.84.255254
86185.4.85.0/24185.4.85.1 to 185.4.85.254185.4.85.255254
87185.4.86.0/24185.4.86.1 to 185.4.86.254185.4.86.255254
88185.4.87.0/24185.4.87.1 to 185.4.87.254185.4.87.255254
89185.4.88.0/24185.4.88.1 to 185.4.88.254185.4.88.255254
90185.4.89.0/24185.4.89.1 to 185.4.89.254185.4.89.255254
91185.4.90.0/24185.4.90.1 to 185.4.90.254185.4.90.255254
92185.4.91.0/24185.4.91.1 to 185.4.91.254185.4.91.255254
93185.4.92.0/24185.4.92.1 to 185.4.92.254185.4.92.255254
94185.4.93.0/24185.4.93.1 to 185.4.93.254185.4.93.255254
95185.4.94.0/24185.4.94.1 to 185.4.94.254185.4.94.255254
96185.4.95.0/24185.4.95.1 to 185.4.95.254185.4.95.255254
97185.4.96.0/24185.4.96.1 to 185.4.96.254185.4.96.255254
98185.4.97.0/24185.4.97.1 to 185.4.97.254185.4.97.255254
99185.4.98.0/24185.4.98.1 to 185.4.98.254185.4.98.255254
100185.4.99.0/24185.4.99.1 to 185.4.99.254185.4.99.255254
101185.4.100.0/24185.4.100.1 to 185.4.100.254185.4.100.255254
102185.4.101.0/24185.4.101.1 to 185.4.101.254185.4.101.255254
103185.4.102.0/24185.4.102.1 to 185.4.102.254185.4.102.255254
104185.4.103.0/24185.4.103.1 to 185.4.103.254185.4.103.255254
105185.4.104.0/24185.4.104.1 to 185.4.104.254185.4.104.255254
106185.4.105.0/24185.4.105.1 to 185.4.105.254185.4.105.255254
107185.4.106.0/24185.4.106.1 to 185.4.106.254185.4.106.255254
108185.4.107.0/24185.4.107.1 to 185.4.107.254185.4.107.255254
109185.4.108.0/24185.4.108.1 to 185.4.108.254185.4.108.255254
110185.4.109.0/24185.4.109.1 to 185.4.109.254185.4.109.255254
111185.4.110.0/24185.4.110.1 to 185.4.110.254185.4.110.255254
112185.4.111.0/24185.4.111.1 to 185.4.111.254185.4.111.255254
113185.4.112.0/24185.4.112.1 to 185.4.112.254185.4.112.255254
114185.4.113.0/24185.4.113.1 to 185.4.113.254185.4.113.255254
115185.4.114.0/24185.4.114.1 to 185.4.114.254185.4.114.255254
116185.4.115.0/24185.4.115.1 to 185.4.115.254185.4.115.255254
117185.4.116.0/24185.4.116.1 to 185.4.116.254185.4.116.255254
118185.4.117.0/24185.4.117.1 to 185.4.117.254185.4.117.255254
119185.4.118.0/24185.4.118.1 to 185.4.118.254185.4.118.255254
120185.4.119.0/24185.4.119.1 to 185.4.119.254185.4.119.255254
121185.4.120.0/24185.4.120.1 to 185.4.120.254185.4.120.255254
122185.4.121.0/24185.4.121.1 to 185.4.121.254185.4.121.255254
123185.4.122.0/24185.4.122.1 to 185.4.122.254185.4.122.255254
124185.4.123.0/24185.4.123.1 to 185.4.123.254185.4.123.255254
125185.4.124.0/24185.4.124.1 to 185.4.124.254185.4.124.255254
126185.4.125.0/24185.4.125.1 to 185.4.125.254185.4.125.255254
127185.4.126.0/24185.4.126.1 to 185.4.126.254185.4.126.255254
128185.4.127.0/24185.4.127.1 to 185.4.127.254185.4.127.255254
129185.4.128.0/24185.4.128.1 to 185.4.128.254185.4.128.255254
130185.4.129.0/24185.4.129.1 to 185.4.129.254185.4.129.255254
131185.4.130.0/24185.4.130.1 to 185.4.130.254185.4.130.255254
132185.4.131.0/24185.4.131.1 to 185.4.131.254185.4.131.255254
133185.4.132.0/24185.4.132.1 to 185.4.132.254185.4.132.255254
134185.4.133.0/24185.4.133.1 to 185.4.133.254185.4.133.255254
135185.4.134.0/24185.4.134.1 to 185.4.134.254185.4.134.255254
136185.4.135.0/24185.4.135.1 to 185.4.135.254185.4.135.255254
137185.4.136.0/24185.4.136.1 to 185.4.136.254185.4.136.255254
138185.4.137.0/24185.4.137.1 to 185.4.137.254185.4.137.255254
139185.4.138.0/24185.4.138.1 to 185.4.138.254185.4.138.255254
140185.4.139.0/24185.4.139.1 to 185.4.139.254185.4.139.255254
141185.4.140.0/24185.4.140.1 to 185.4.140.254185.4.140.255254
142185.4.141.0/24185.4.141.1 to 185.4.141.254185.4.141.255254
143185.4.142.0/24185.4.142.1 to 185.4.142.254185.4.142.255254
144185.4.143.0/24185.4.143.1 to 185.4.143.254185.4.143.255254
145185.4.144.0/24185.4.144.1 to 185.4.144.254185.4.144.255254
146185.4.145.0/24185.4.145.1 to 185.4.145.254185.4.145.255254
147185.4.146.0/24185.4.146.1 to 185.4.146.254185.4.146.255254
148185.4.147.0/24185.4.147.1 to 185.4.147.254185.4.147.255254
149185.4.148.0/24185.4.148.1 to 185.4.148.254185.4.148.255254
150185.4.149.0/24185.4.149.1 to 185.4.149.254185.4.149.255254
151185.4.150.0/24185.4.150.1 to 185.4.150.254185.4.150.255254
152185.4.151.0/24185.4.151.1 to 185.4.151.254185.4.151.255254
153185.4.152.0/24185.4.152.1 to 185.4.152.254185.4.152.255254
154185.4.153.0/24185.4.153.1 to 185.4.153.254185.4.153.255254
155185.4.154.0/24185.4.154.1 to 185.4.154.254185.4.154.255254
156185.4.155.0/24185.4.155.1 to 185.4.155.254185.4.155.255254
157185.4.156.0/24185.4.156.1 to 185.4.156.254185.4.156.255254
158185.4.157.0/24185.4.157.1 to 185.4.157.254185.4.157.255254
159185.4.158.0/24185.4.158.1 to 185.4.158.254185.4.158.255254
160185.4.159.0/24185.4.159.1 to 185.4.159.254185.4.159.255254
161185.4.160.0/24185.4.160.1 to 185.4.160.254185.4.160.255254
162185.4.161.0/24185.4.161.1 to 185.4.161.254185.4.161.255254
163185.4.162.0/24185.4.162.1 to 185.4.162.254185.4.162.255254
164185.4.163.0/24185.4.163.1 to 185.4.163.254185.4.163.255254
165185.4.164.0/24185.4.164.1 to 185.4.164.254185.4.164.255254
166185.4.165.0/24185.4.165.1 to 185.4.165.254185.4.165.255254
167185.4.166.0/24185.4.166.1 to 185.4.166.254185.4.166.255254
168185.4.167.0/24185.4.167.1 to 185.4.167.254185.4.167.255254
169185.4.168.0/24185.4.168.1 to 185.4.168.254185.4.168.255254
170185.4.169.0/24185.4.169.1 to 185.4.169.254185.4.169.255254
171185.4.170.0/24185.4.170.1 to 185.4.170.254185.4.170.255254
172185.4.171.0/24185.4.171.1 to 185.4.171.254185.4.171.255254
173185.4.172.0/24185.4.172.1 to 185.4.172.254185.4.172.255254
174185.4.173.0/24185.4.173.1 to 185.4.173.254185.4.173.255254
175185.4.174.0/24185.4.174.1 to 185.4.174.254185.4.174.255254
176185.4.175.0/24185.4.175.1 to 185.4.175.254185.4.175.255254
177185.4.176.0/24185.4.176.1 to 185.4.176.254185.4.176.255254
178185.4.177.0/24185.4.177.1 to 185.4.177.254185.4.177.255254
179185.4.178.0/24185.4.178.1 to 185.4.178.254185.4.178.255254
180185.4.179.0/24185.4.179.1 to 185.4.179.254185.4.179.255254
181185.4.180.0/24185.4.180.1 to 185.4.180.254185.4.180.255254
182185.4.181.0/24185.4.181.1 to 185.4.181.254185.4.181.255254
183185.4.182.0/24185.4.182.1 to 185.4.182.254185.4.182.255254
184185.4.183.0/24185.4.183.1 to 185.4.183.254185.4.183.255254
185185.4.184.0/24185.4.184.1 to 185.4.184.254185.4.184.255254
186185.4.185.0/24185.4.185.1 to 185.4.185.254185.4.185.255254
187185.4.186.0/24185.4.186.1 to 185.4.186.254185.4.186.255254
188185.4.187.0/24185.4.187.1 to 185.4.187.254185.4.187.255254
189185.4.188.0/24185.4.188.1 to 185.4.188.254185.4.188.255254
190185.4.189.0/24185.4.189.1 to 185.4.189.254185.4.189.255254
191185.4.190.0/24185.4.190.1 to 185.4.190.254185.4.190.255254
192185.4.191.0/24185.4.191.1 to 185.4.191.254185.4.191.255254
193185.4.192.0/24185.4.192.1 to 185.4.192.254185.4.192.255254
194185.4.193.0/24185.4.193.1 to 185.4.193.254185.4.193.255254
195185.4.194.0/24185.4.194.1 to 185.4.194.254185.4.194.255254
196185.4.195.0/24185.4.195.1 to 185.4.195.254185.4.195.255254
197185.4.196.0/24185.4.196.1 to 185.4.196.254185.4.196.255254
198185.4.197.0/24185.4.197.1 to 185.4.197.254185.4.197.255254
199185.4.198.0/24185.4.198.1 to 185.4.198.254185.4.198.255254
200185.4.199.0/24185.4.199.1 to 185.4.199.254185.4.199.255254
201185.4.200.0/24185.4.200.1 to 185.4.200.254185.4.200.255254
202185.4.201.0/24185.4.201.1 to 185.4.201.254185.4.201.255254
203185.4.202.0/24185.4.202.1 to 185.4.202.254185.4.202.255254
204185.4.203.0/24185.4.203.1 to 185.4.203.254185.4.203.255254
205185.4.204.0/24185.4.204.1 to 185.4.204.254185.4.204.255254
206185.4.205.0/24185.4.205.1 to 185.4.205.254185.4.205.255254
207185.4.206.0/24185.4.206.1 to 185.4.206.254185.4.206.255254
208185.4.207.0/24185.4.207.1 to 185.4.207.254185.4.207.255254
209185.4.208.0/24185.4.208.1 to 185.4.208.254185.4.208.255254
210185.4.209.0/24185.4.209.1 to 185.4.209.254185.4.209.255254
211185.4.210.0/24185.4.210.1 to 185.4.210.254185.4.210.255254
212185.4.211.0/24185.4.211.1 to 185.4.211.254185.4.211.255254
213185.4.212.0/24185.4.212.1 to 185.4.212.254185.4.212.255254
214185.4.213.0/24185.4.213.1 to 185.4.213.254185.4.213.255254
215185.4.214.0/24185.4.214.1 to 185.4.214.254185.4.214.255254
216185.4.215.0/24185.4.215.1 to 185.4.215.254185.4.215.255254
217185.4.216.0/24185.4.216.1 to 185.4.216.254185.4.216.255254
218185.4.217.0/24185.4.217.1 to 185.4.217.254185.4.217.255254
219185.4.218.0/24185.4.218.1 to 185.4.218.254185.4.218.255254
220185.4.219.0/24185.4.219.1 to 185.4.219.254185.4.219.255254
221185.4.220.0/24185.4.220.1 to 185.4.220.254185.4.220.255254
222185.4.221.0/24185.4.221.1 to 185.4.221.254185.4.221.255254
223185.4.222.0/24185.4.222.1 to 185.4.222.254185.4.222.255254
224185.4.223.0/24185.4.223.1 to 185.4.223.254185.4.223.255254
225185.4.224.0/24185.4.224.1 to 185.4.224.254185.4.224.255254
226185.4.225.0/24185.4.225.1 to 185.4.225.254185.4.225.255254
227185.4.226.0/24185.4.226.1 to 185.4.226.254185.4.226.255254
228185.4.227.0/24185.4.227.1 to 185.4.227.254185.4.227.255254
229185.4.228.0/24185.4.228.1 to 185.4.228.254185.4.228.255254
230185.4.229.0/24185.4.229.1 to 185.4.229.254185.4.229.255254
231185.4.230.0/24185.4.230.1 to 185.4.230.254185.4.230.255254
232185.4.231.0/24185.4.231.1 to 185.4.231.254185.4.231.255254
233185.4.232.0/24185.4.232.1 to 185.4.232.254185.4.232.255254
234185.4.233.0/24185.4.233.1 to 185.4.233.254185.4.233.255254
235185.4.234.0/24185.4.234.1 to 185.4.234.254185.4.234.255254
236185.4.235.0/24185.4.235.1 to 185.4.235.254185.4.235.255254
237185.4.236.0/24185.4.236.1 to 185.4.236.254185.4.236.255254
238185.4.237.0/24185.4.237.1 to 185.4.237.254185.4.237.255254
239185.4.238.0/24185.4.238.1 to 185.4.238.254185.4.238.255254
240185.4.239.0/24185.4.239.1 to 185.4.239.254185.4.239.255254
241185.4.240.0/24185.4.240.1 to 185.4.240.254185.4.240.255254
242185.4.241.0/24185.4.241.1 to 185.4.241.254185.4.241.255254
243185.4.242.0/24185.4.242.1 to 185.4.242.254185.4.242.255254
244185.4.243.0/24185.4.243.1 to 185.4.243.254185.4.243.255254
245185.4.244.0/24185.4.244.1 to 185.4.244.254185.4.244.255254
246185.4.245.0/24185.4.245.1 to 185.4.245.254185.4.245.255254
247185.4.246.0/24185.4.246.1 to 185.4.246.254185.4.246.255254
248185.4.247.0/24185.4.247.1 to 185.4.247.254185.4.247.255254
249185.4.248.0/24185.4.248.1 to 185.4.248.254185.4.248.255254
250185.4.249.0/24185.4.249.1 to 185.4.249.254185.4.249.255254
251185.4.250.0/24185.4.250.1 to 185.4.250.254185.4.250.255254
252185.4.251.0/24185.4.251.1 to 185.4.251.254185.4.251.255254
253185.4.252.0/24185.4.252.1 to 185.4.252.254185.4.252.255254
254185.4.253.0/24185.4.253.1 to 185.4.253.254185.4.253.255254
255185.4.254.0/24185.4.254.1 to 185.4.254.254185.4.254.255254
256185.4.255.0/24185.4.255.1 to 185.4.255.254185.4.255.255254

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.