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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.

Network168.0.0.0/5
Usable hosts134,217,726
Subnet mask248.0.0.0
Addresses134,217,728
Network address
168.0.0.0
Broadcast address
175.255.255.255
First usable
168.0.0.1
Last usable
175.255.255.254
Usable hosts
134,217,726 (134,217,728 less the network and broadcast addresses)
Subnet mask
248.0.0.0
Wildcard mask
7.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/5
Type
Public public
Old class
B (default /16)
As numbers
Hex A8000000 · Integer 2818572288 to 2952790015
Reverse DNS zones
168.in-addr.arpa
169.in-addr.arpa
170.in-addr.arpa
171.in-addr.arpa
172.in-addr.arpa
173.in-addr.arpa
174.in-addr.arpa
175.in-addr.arpa
/5 is not on a 8-bit boundary, so it takes 8 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10101000.00000000.00000000.00000000168.0.0.0
Subnet mask11111000.00000000.00000000.00000000248.0.0.0
Network10101000.00000000.00000000.00000000168.0.0.0
Broadcast10101111.11111111.11111111.11111111175.255.255.255
Split into smaller subnets/16
/6 (2)/7 (4)/8 (8)/9 (16)/10 (32)/11 (64)/12 (128)/13 (256)/14 (512)/15 (1,024)/16 (2,048)/17 (4,096)

168.0.0.0/5 makes 2,048 subnets of /16; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1168.0.0.0/16168.0.0.1 to 168.0.255.254168.0.255.25565,534
2168.1.0.0/16168.1.0.1 to 168.1.255.254168.1.255.25565,534
3168.2.0.0/16168.2.0.1 to 168.2.255.254168.2.255.25565,534
4168.3.0.0/16168.3.0.1 to 168.3.255.254168.3.255.25565,534
5168.4.0.0/16168.4.0.1 to 168.4.255.254168.4.255.25565,534
6168.5.0.0/16168.5.0.1 to 168.5.255.254168.5.255.25565,534
7168.6.0.0/16168.6.0.1 to 168.6.255.254168.6.255.25565,534
8168.7.0.0/16168.7.0.1 to 168.7.255.254168.7.255.25565,534
9168.8.0.0/16168.8.0.1 to 168.8.255.254168.8.255.25565,534
10168.9.0.0/16168.9.0.1 to 168.9.255.254168.9.255.25565,534
11168.10.0.0/16168.10.0.1 to 168.10.255.254168.10.255.25565,534
12168.11.0.0/16168.11.0.1 to 168.11.255.254168.11.255.25565,534
13168.12.0.0/16168.12.0.1 to 168.12.255.254168.12.255.25565,534
14168.13.0.0/16168.13.0.1 to 168.13.255.254168.13.255.25565,534
15168.14.0.0/16168.14.0.1 to 168.14.255.254168.14.255.25565,534
16168.15.0.0/16168.15.0.1 to 168.15.255.254168.15.255.25565,534
17168.16.0.0/16168.16.0.1 to 168.16.255.254168.16.255.25565,534
18168.17.0.0/16168.17.0.1 to 168.17.255.254168.17.255.25565,534
19168.18.0.0/16168.18.0.1 to 168.18.255.254168.18.255.25565,534
20168.19.0.0/16168.19.0.1 to 168.19.255.254168.19.255.25565,534
21168.20.0.0/16168.20.0.1 to 168.20.255.254168.20.255.25565,534
22168.21.0.0/16168.21.0.1 to 168.21.255.254168.21.255.25565,534
23168.22.0.0/16168.22.0.1 to 168.22.255.254168.22.255.25565,534
24168.23.0.0/16168.23.0.1 to 168.23.255.254168.23.255.25565,534
25168.24.0.0/16168.24.0.1 to 168.24.255.254168.24.255.25565,534
26168.25.0.0/16168.25.0.1 to 168.25.255.254168.25.255.25565,534
27168.26.0.0/16168.26.0.1 to 168.26.255.254168.26.255.25565,534
28168.27.0.0/16168.27.0.1 to 168.27.255.254168.27.255.25565,534
29168.28.0.0/16168.28.0.1 to 168.28.255.254168.28.255.25565,534
30168.29.0.0/16168.29.0.1 to 168.29.255.254168.29.255.25565,534
31168.30.0.0/16168.30.0.1 to 168.30.255.254168.30.255.25565,534
32168.31.0.0/16168.31.0.1 to 168.31.255.254168.31.255.25565,534
33168.32.0.0/16168.32.0.1 to 168.32.255.254168.32.255.25565,534
34168.33.0.0/16168.33.0.1 to 168.33.255.254168.33.255.25565,534
35168.34.0.0/16168.34.0.1 to 168.34.255.254168.34.255.25565,534
36168.35.0.0/16168.35.0.1 to 168.35.255.254168.35.255.25565,534
37168.36.0.0/16168.36.0.1 to 168.36.255.254168.36.255.25565,534
38168.37.0.0/16168.37.0.1 to 168.37.255.254168.37.255.25565,534
39168.38.0.0/16168.38.0.1 to 168.38.255.254168.38.255.25565,534
40168.39.0.0/16168.39.0.1 to 168.39.255.254168.39.255.25565,534
41168.40.0.0/16168.40.0.1 to 168.40.255.254168.40.255.25565,534
42168.41.0.0/16168.41.0.1 to 168.41.255.254168.41.255.25565,534
43168.42.0.0/16168.42.0.1 to 168.42.255.254168.42.255.25565,534
44168.43.0.0/16168.43.0.1 to 168.43.255.254168.43.255.25565,534
45168.44.0.0/16168.44.0.1 to 168.44.255.254168.44.255.25565,534
46168.45.0.0/16168.45.0.1 to 168.45.255.254168.45.255.25565,534
47168.46.0.0/16168.46.0.1 to 168.46.255.254168.46.255.25565,534
48168.47.0.0/16168.47.0.1 to 168.47.255.254168.47.255.25565,534
49168.48.0.0/16168.48.0.1 to 168.48.255.254168.48.255.25565,534
50168.49.0.0/16168.49.0.1 to 168.49.255.254168.49.255.25565,534
51168.50.0.0/16168.50.0.1 to 168.50.255.254168.50.255.25565,534
52168.51.0.0/16168.51.0.1 to 168.51.255.254168.51.255.25565,534
53168.52.0.0/16168.52.0.1 to 168.52.255.254168.52.255.25565,534
54168.53.0.0/16168.53.0.1 to 168.53.255.254168.53.255.25565,534
55168.54.0.0/16168.54.0.1 to 168.54.255.254168.54.255.25565,534
56168.55.0.0/16168.55.0.1 to 168.55.255.254168.55.255.25565,534
57168.56.0.0/16168.56.0.1 to 168.56.255.254168.56.255.25565,534
58168.57.0.0/16168.57.0.1 to 168.57.255.254168.57.255.25565,534
59168.58.0.0/16168.58.0.1 to 168.58.255.254168.58.255.25565,534
60168.59.0.0/16168.59.0.1 to 168.59.255.254168.59.255.25565,534
61168.60.0.0/16168.60.0.1 to 168.60.255.254168.60.255.25565,534
62168.61.0.0/16168.61.0.1 to 168.61.255.254168.61.255.25565,534
63168.62.0.0/16168.62.0.1 to 168.62.255.254168.62.255.25565,534
64168.63.0.0/16168.63.0.1 to 168.63.255.254168.63.255.25565,534
65168.64.0.0/16168.64.0.1 to 168.64.255.254168.64.255.25565,534
66168.65.0.0/16168.65.0.1 to 168.65.255.254168.65.255.25565,534
67168.66.0.0/16168.66.0.1 to 168.66.255.254168.66.255.25565,534
68168.67.0.0/16168.67.0.1 to 168.67.255.254168.67.255.25565,534
69168.68.0.0/16168.68.0.1 to 168.68.255.254168.68.255.25565,534
70168.69.0.0/16168.69.0.1 to 168.69.255.254168.69.255.25565,534
71168.70.0.0/16168.70.0.1 to 168.70.255.254168.70.255.25565,534
72168.71.0.0/16168.71.0.1 to 168.71.255.254168.71.255.25565,534
73168.72.0.0/16168.72.0.1 to 168.72.255.254168.72.255.25565,534
74168.73.0.0/16168.73.0.1 to 168.73.255.254168.73.255.25565,534
75168.74.0.0/16168.74.0.1 to 168.74.255.254168.74.255.25565,534
76168.75.0.0/16168.75.0.1 to 168.75.255.254168.75.255.25565,534
77168.76.0.0/16168.76.0.1 to 168.76.255.254168.76.255.25565,534
78168.77.0.0/16168.77.0.1 to 168.77.255.254168.77.255.25565,534
79168.78.0.0/16168.78.0.1 to 168.78.255.254168.78.255.25565,534
80168.79.0.0/16168.79.0.1 to 168.79.255.254168.79.255.25565,534
81168.80.0.0/16168.80.0.1 to 168.80.255.254168.80.255.25565,534
82168.81.0.0/16168.81.0.1 to 168.81.255.254168.81.255.25565,534
83168.82.0.0/16168.82.0.1 to 168.82.255.254168.82.255.25565,534
84168.83.0.0/16168.83.0.1 to 168.83.255.254168.83.255.25565,534
85168.84.0.0/16168.84.0.1 to 168.84.255.254168.84.255.25565,534
86168.85.0.0/16168.85.0.1 to 168.85.255.254168.85.255.25565,534
87168.86.0.0/16168.86.0.1 to 168.86.255.254168.86.255.25565,534
88168.87.0.0/16168.87.0.1 to 168.87.255.254168.87.255.25565,534
89168.88.0.0/16168.88.0.1 to 168.88.255.254168.88.255.25565,534
90168.89.0.0/16168.89.0.1 to 168.89.255.254168.89.255.25565,534
91168.90.0.0/16168.90.0.1 to 168.90.255.254168.90.255.25565,534
92168.91.0.0/16168.91.0.1 to 168.91.255.254168.91.255.25565,534
93168.92.0.0/16168.92.0.1 to 168.92.255.254168.92.255.25565,534
94168.93.0.0/16168.93.0.1 to 168.93.255.254168.93.255.25565,534
95168.94.0.0/16168.94.0.1 to 168.94.255.254168.94.255.25565,534
96168.95.0.0/16168.95.0.1 to 168.95.255.254168.95.255.25565,534
97168.96.0.0/16168.96.0.1 to 168.96.255.254168.96.255.25565,534
98168.97.0.0/16168.97.0.1 to 168.97.255.254168.97.255.25565,534
99168.98.0.0/16168.98.0.1 to 168.98.255.254168.98.255.25565,534
100168.99.0.0/16168.99.0.1 to 168.99.255.254168.99.255.25565,534
101168.100.0.0/16168.100.0.1 to 168.100.255.254168.100.255.25565,534
102168.101.0.0/16168.101.0.1 to 168.101.255.254168.101.255.25565,534
103168.102.0.0/16168.102.0.1 to 168.102.255.254168.102.255.25565,534
104168.103.0.0/16168.103.0.1 to 168.103.255.254168.103.255.25565,534
105168.104.0.0/16168.104.0.1 to 168.104.255.254168.104.255.25565,534
106168.105.0.0/16168.105.0.1 to 168.105.255.254168.105.255.25565,534
107168.106.0.0/16168.106.0.1 to 168.106.255.254168.106.255.25565,534
108168.107.0.0/16168.107.0.1 to 168.107.255.254168.107.255.25565,534
109168.108.0.0/16168.108.0.1 to 168.108.255.254168.108.255.25565,534
110168.109.0.0/16168.109.0.1 to 168.109.255.254168.109.255.25565,534
111168.110.0.0/16168.110.0.1 to 168.110.255.254168.110.255.25565,534
112168.111.0.0/16168.111.0.1 to 168.111.255.254168.111.255.25565,534
113168.112.0.0/16168.112.0.1 to 168.112.255.254168.112.255.25565,534
114168.113.0.0/16168.113.0.1 to 168.113.255.254168.113.255.25565,534
115168.114.0.0/16168.114.0.1 to 168.114.255.254168.114.255.25565,534
116168.115.0.0/16168.115.0.1 to 168.115.255.254168.115.255.25565,534
117168.116.0.0/16168.116.0.1 to 168.116.255.254168.116.255.25565,534
118168.117.0.0/16168.117.0.1 to 168.117.255.254168.117.255.25565,534
119168.118.0.0/16168.118.0.1 to 168.118.255.254168.118.255.25565,534
120168.119.0.0/16168.119.0.1 to 168.119.255.254168.119.255.25565,534
121168.120.0.0/16168.120.0.1 to 168.120.255.254168.120.255.25565,534
122168.121.0.0/16168.121.0.1 to 168.121.255.254168.121.255.25565,534
123168.122.0.0/16168.122.0.1 to 168.122.255.254168.122.255.25565,534
124168.123.0.0/16168.123.0.1 to 168.123.255.254168.123.255.25565,534
125168.124.0.0/16168.124.0.1 to 168.124.255.254168.124.255.25565,534
126168.125.0.0/16168.125.0.1 to 168.125.255.254168.125.255.25565,534
127168.126.0.0/16168.126.0.1 to 168.126.255.254168.126.255.25565,534
128168.127.0.0/16168.127.0.1 to 168.127.255.254168.127.255.25565,534
129168.128.0.0/16168.128.0.1 to 168.128.255.254168.128.255.25565,534
130168.129.0.0/16168.129.0.1 to 168.129.255.254168.129.255.25565,534
131168.130.0.0/16168.130.0.1 to 168.130.255.254168.130.255.25565,534
132168.131.0.0/16168.131.0.1 to 168.131.255.254168.131.255.25565,534
133168.132.0.0/16168.132.0.1 to 168.132.255.254168.132.255.25565,534
134168.133.0.0/16168.133.0.1 to 168.133.255.254168.133.255.25565,534
135168.134.0.0/16168.134.0.1 to 168.134.255.254168.134.255.25565,534
136168.135.0.0/16168.135.0.1 to 168.135.255.254168.135.255.25565,534
137168.136.0.0/16168.136.0.1 to 168.136.255.254168.136.255.25565,534
138168.137.0.0/16168.137.0.1 to 168.137.255.254168.137.255.25565,534
139168.138.0.0/16168.138.0.1 to 168.138.255.254168.138.255.25565,534
140168.139.0.0/16168.139.0.1 to 168.139.255.254168.139.255.25565,534
141168.140.0.0/16168.140.0.1 to 168.140.255.254168.140.255.25565,534
142168.141.0.0/16168.141.0.1 to 168.141.255.254168.141.255.25565,534
143168.142.0.0/16168.142.0.1 to 168.142.255.254168.142.255.25565,534
144168.143.0.0/16168.143.0.1 to 168.143.255.254168.143.255.25565,534
145168.144.0.0/16168.144.0.1 to 168.144.255.254168.144.255.25565,534
146168.145.0.0/16168.145.0.1 to 168.145.255.254168.145.255.25565,534
147168.146.0.0/16168.146.0.1 to 168.146.255.254168.146.255.25565,534
148168.147.0.0/16168.147.0.1 to 168.147.255.254168.147.255.25565,534
149168.148.0.0/16168.148.0.1 to 168.148.255.254168.148.255.25565,534
150168.149.0.0/16168.149.0.1 to 168.149.255.254168.149.255.25565,534
151168.150.0.0/16168.150.0.1 to 168.150.255.254168.150.255.25565,534
152168.151.0.0/16168.151.0.1 to 168.151.255.254168.151.255.25565,534
153168.152.0.0/16168.152.0.1 to 168.152.255.254168.152.255.25565,534
154168.153.0.0/16168.153.0.1 to 168.153.255.254168.153.255.25565,534
155168.154.0.0/16168.154.0.1 to 168.154.255.254168.154.255.25565,534
156168.155.0.0/16168.155.0.1 to 168.155.255.254168.155.255.25565,534
157168.156.0.0/16168.156.0.1 to 168.156.255.254168.156.255.25565,534
158168.157.0.0/16168.157.0.1 to 168.157.255.254168.157.255.25565,534
159168.158.0.0/16168.158.0.1 to 168.158.255.254168.158.255.25565,534
160168.159.0.0/16168.159.0.1 to 168.159.255.254168.159.255.25565,534
161168.160.0.0/16168.160.0.1 to 168.160.255.254168.160.255.25565,534
162168.161.0.0/16168.161.0.1 to 168.161.255.254168.161.255.25565,534
163168.162.0.0/16168.162.0.1 to 168.162.255.254168.162.255.25565,534
164168.163.0.0/16168.163.0.1 to 168.163.255.254168.163.255.25565,534
165168.164.0.0/16168.164.0.1 to 168.164.255.254168.164.255.25565,534
166168.165.0.0/16168.165.0.1 to 168.165.255.254168.165.255.25565,534
167168.166.0.0/16168.166.0.1 to 168.166.255.254168.166.255.25565,534
168168.167.0.0/16168.167.0.1 to 168.167.255.254168.167.255.25565,534
169168.168.0.0/16168.168.0.1 to 168.168.255.254168.168.255.25565,534
170168.169.0.0/16168.169.0.1 to 168.169.255.254168.169.255.25565,534
171168.170.0.0/16168.170.0.1 to 168.170.255.254168.170.255.25565,534
172168.171.0.0/16168.171.0.1 to 168.171.255.254168.171.255.25565,534
173168.172.0.0/16168.172.0.1 to 168.172.255.254168.172.255.25565,534
174168.173.0.0/16168.173.0.1 to 168.173.255.254168.173.255.25565,534
175168.174.0.0/16168.174.0.1 to 168.174.255.254168.174.255.25565,534
176168.175.0.0/16168.175.0.1 to 168.175.255.254168.175.255.25565,534
177168.176.0.0/16168.176.0.1 to 168.176.255.254168.176.255.25565,534
178168.177.0.0/16168.177.0.1 to 168.177.255.254168.177.255.25565,534
179168.178.0.0/16168.178.0.1 to 168.178.255.254168.178.255.25565,534
180168.179.0.0/16168.179.0.1 to 168.179.255.254168.179.255.25565,534
181168.180.0.0/16168.180.0.1 to 168.180.255.254168.180.255.25565,534
182168.181.0.0/16168.181.0.1 to 168.181.255.254168.181.255.25565,534
183168.182.0.0/16168.182.0.1 to 168.182.255.254168.182.255.25565,534
184168.183.0.0/16168.183.0.1 to 168.183.255.254168.183.255.25565,534
185168.184.0.0/16168.184.0.1 to 168.184.255.254168.184.255.25565,534
186168.185.0.0/16168.185.0.1 to 168.185.255.254168.185.255.25565,534
187168.186.0.0/16168.186.0.1 to 168.186.255.254168.186.255.25565,534
188168.187.0.0/16168.187.0.1 to 168.187.255.254168.187.255.25565,534
189168.188.0.0/16168.188.0.1 to 168.188.255.254168.188.255.25565,534
190168.189.0.0/16168.189.0.1 to 168.189.255.254168.189.255.25565,534
191168.190.0.0/16168.190.0.1 to 168.190.255.254168.190.255.25565,534
192168.191.0.0/16168.191.0.1 to 168.191.255.254168.191.255.25565,534
193168.192.0.0/16168.192.0.1 to 168.192.255.254168.192.255.25565,534
194168.193.0.0/16168.193.0.1 to 168.193.255.254168.193.255.25565,534
195168.194.0.0/16168.194.0.1 to 168.194.255.254168.194.255.25565,534
196168.195.0.0/16168.195.0.1 to 168.195.255.254168.195.255.25565,534
197168.196.0.0/16168.196.0.1 to 168.196.255.254168.196.255.25565,534
198168.197.0.0/16168.197.0.1 to 168.197.255.254168.197.255.25565,534
199168.198.0.0/16168.198.0.1 to 168.198.255.254168.198.255.25565,534
200168.199.0.0/16168.199.0.1 to 168.199.255.254168.199.255.25565,534
201168.200.0.0/16168.200.0.1 to 168.200.255.254168.200.255.25565,534
202168.201.0.0/16168.201.0.1 to 168.201.255.254168.201.255.25565,534
203168.202.0.0/16168.202.0.1 to 168.202.255.254168.202.255.25565,534
204168.203.0.0/16168.203.0.1 to 168.203.255.254168.203.255.25565,534
205168.204.0.0/16168.204.0.1 to 168.204.255.254168.204.255.25565,534
206168.205.0.0/16168.205.0.1 to 168.205.255.254168.205.255.25565,534
207168.206.0.0/16168.206.0.1 to 168.206.255.254168.206.255.25565,534
208168.207.0.0/16168.207.0.1 to 168.207.255.254168.207.255.25565,534
209168.208.0.0/16168.208.0.1 to 168.208.255.254168.208.255.25565,534
210168.209.0.0/16168.209.0.1 to 168.209.255.254168.209.255.25565,534
211168.210.0.0/16168.210.0.1 to 168.210.255.254168.210.255.25565,534
212168.211.0.0/16168.211.0.1 to 168.211.255.254168.211.255.25565,534
213168.212.0.0/16168.212.0.1 to 168.212.255.254168.212.255.25565,534
214168.213.0.0/16168.213.0.1 to 168.213.255.254168.213.255.25565,534
215168.214.0.0/16168.214.0.1 to 168.214.255.254168.214.255.25565,534
216168.215.0.0/16168.215.0.1 to 168.215.255.254168.215.255.25565,534
217168.216.0.0/16168.216.0.1 to 168.216.255.254168.216.255.25565,534
218168.217.0.0/16168.217.0.1 to 168.217.255.254168.217.255.25565,534
219168.218.0.0/16168.218.0.1 to 168.218.255.254168.218.255.25565,534
220168.219.0.0/16168.219.0.1 to 168.219.255.254168.219.255.25565,534
221168.220.0.0/16168.220.0.1 to 168.220.255.254168.220.255.25565,534
222168.221.0.0/16168.221.0.1 to 168.221.255.254168.221.255.25565,534
223168.222.0.0/16168.222.0.1 to 168.222.255.254168.222.255.25565,534
224168.223.0.0/16168.223.0.1 to 168.223.255.254168.223.255.25565,534
225168.224.0.0/16168.224.0.1 to 168.224.255.254168.224.255.25565,534
226168.225.0.0/16168.225.0.1 to 168.225.255.254168.225.255.25565,534
227168.226.0.0/16168.226.0.1 to 168.226.255.254168.226.255.25565,534
228168.227.0.0/16168.227.0.1 to 168.227.255.254168.227.255.25565,534
229168.228.0.0/16168.228.0.1 to 168.228.255.254168.228.255.25565,534
230168.229.0.0/16168.229.0.1 to 168.229.255.254168.229.255.25565,534
231168.230.0.0/16168.230.0.1 to 168.230.255.254168.230.255.25565,534
232168.231.0.0/16168.231.0.1 to 168.231.255.254168.231.255.25565,534
233168.232.0.0/16168.232.0.1 to 168.232.255.254168.232.255.25565,534
234168.233.0.0/16168.233.0.1 to 168.233.255.254168.233.255.25565,534
235168.234.0.0/16168.234.0.1 to 168.234.255.254168.234.255.25565,534
236168.235.0.0/16168.235.0.1 to 168.235.255.254168.235.255.25565,534
237168.236.0.0/16168.236.0.1 to 168.236.255.254168.236.255.25565,534
238168.237.0.0/16168.237.0.1 to 168.237.255.254168.237.255.25565,534
239168.238.0.0/16168.238.0.1 to 168.238.255.254168.238.255.25565,534
240168.239.0.0/16168.239.0.1 to 168.239.255.254168.239.255.25565,534
241168.240.0.0/16168.240.0.1 to 168.240.255.254168.240.255.25565,534
242168.241.0.0/16168.241.0.1 to 168.241.255.254168.241.255.25565,534
243168.242.0.0/16168.242.0.1 to 168.242.255.254168.242.255.25565,534
244168.243.0.0/16168.243.0.1 to 168.243.255.254168.243.255.25565,534
245168.244.0.0/16168.244.0.1 to 168.244.255.254168.244.255.25565,534
246168.245.0.0/16168.245.0.1 to 168.245.255.254168.245.255.25565,534
247168.246.0.0/16168.246.0.1 to 168.246.255.254168.246.255.25565,534
248168.247.0.0/16168.247.0.1 to 168.247.255.254168.247.255.25565,534
249168.248.0.0/16168.248.0.1 to 168.248.255.254168.248.255.25565,534
250168.249.0.0/16168.249.0.1 to 168.249.255.254168.249.255.25565,534
251168.250.0.0/16168.250.0.1 to 168.250.255.254168.250.255.25565,534
252168.251.0.0/16168.251.0.1 to 168.251.255.254168.251.255.25565,534
253168.252.0.0/16168.252.0.1 to 168.252.255.254168.252.255.25565,534
254168.253.0.0/16168.253.0.1 to 168.253.255.254168.253.255.25565,534
255168.254.0.0/16168.254.0.1 to 168.254.255.254168.254.255.25565,534
256168.255.0.0/16168.255.0.1 to 168.255.255.254168.255.255.25565,534

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.