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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/14
/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 512 subnets of /14; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1168.0.0.0/14168.0.0.1 to 168.3.255.254168.3.255.255262,142
2168.4.0.0/14168.4.0.1 to 168.7.255.254168.7.255.255262,142
3168.8.0.0/14168.8.0.1 to 168.11.255.254168.11.255.255262,142
4168.12.0.0/14168.12.0.1 to 168.15.255.254168.15.255.255262,142
5168.16.0.0/14168.16.0.1 to 168.19.255.254168.19.255.255262,142
6168.20.0.0/14168.20.0.1 to 168.23.255.254168.23.255.255262,142
7168.24.0.0/14168.24.0.1 to 168.27.255.254168.27.255.255262,142
8168.28.0.0/14168.28.0.1 to 168.31.255.254168.31.255.255262,142
9168.32.0.0/14168.32.0.1 to 168.35.255.254168.35.255.255262,142
10168.36.0.0/14168.36.0.1 to 168.39.255.254168.39.255.255262,142
11168.40.0.0/14168.40.0.1 to 168.43.255.254168.43.255.255262,142
12168.44.0.0/14168.44.0.1 to 168.47.255.254168.47.255.255262,142
13168.48.0.0/14168.48.0.1 to 168.51.255.254168.51.255.255262,142
14168.52.0.0/14168.52.0.1 to 168.55.255.254168.55.255.255262,142
15168.56.0.0/14168.56.0.1 to 168.59.255.254168.59.255.255262,142
16168.60.0.0/14168.60.0.1 to 168.63.255.254168.63.255.255262,142
17168.64.0.0/14168.64.0.1 to 168.67.255.254168.67.255.255262,142
18168.68.0.0/14168.68.0.1 to 168.71.255.254168.71.255.255262,142
19168.72.0.0/14168.72.0.1 to 168.75.255.254168.75.255.255262,142
20168.76.0.0/14168.76.0.1 to 168.79.255.254168.79.255.255262,142
21168.80.0.0/14168.80.0.1 to 168.83.255.254168.83.255.255262,142
22168.84.0.0/14168.84.0.1 to 168.87.255.254168.87.255.255262,142
23168.88.0.0/14168.88.0.1 to 168.91.255.254168.91.255.255262,142
24168.92.0.0/14168.92.0.1 to 168.95.255.254168.95.255.255262,142
25168.96.0.0/14168.96.0.1 to 168.99.255.254168.99.255.255262,142
26168.100.0.0/14168.100.0.1 to 168.103.255.254168.103.255.255262,142
27168.104.0.0/14168.104.0.1 to 168.107.255.254168.107.255.255262,142
28168.108.0.0/14168.108.0.1 to 168.111.255.254168.111.255.255262,142
29168.112.0.0/14168.112.0.1 to 168.115.255.254168.115.255.255262,142
30168.116.0.0/14168.116.0.1 to 168.119.255.254168.119.255.255262,142
31168.120.0.0/14168.120.0.1 to 168.123.255.254168.123.255.255262,142
32168.124.0.0/14168.124.0.1 to 168.127.255.254168.127.255.255262,142
33168.128.0.0/14168.128.0.1 to 168.131.255.254168.131.255.255262,142
34168.132.0.0/14168.132.0.1 to 168.135.255.254168.135.255.255262,142
35168.136.0.0/14168.136.0.1 to 168.139.255.254168.139.255.255262,142
36168.140.0.0/14168.140.0.1 to 168.143.255.254168.143.255.255262,142
37168.144.0.0/14168.144.0.1 to 168.147.255.254168.147.255.255262,142
38168.148.0.0/14168.148.0.1 to 168.151.255.254168.151.255.255262,142
39168.152.0.0/14168.152.0.1 to 168.155.255.254168.155.255.255262,142
40168.156.0.0/14168.156.0.1 to 168.159.255.254168.159.255.255262,142
41168.160.0.0/14168.160.0.1 to 168.163.255.254168.163.255.255262,142
42168.164.0.0/14168.164.0.1 to 168.167.255.254168.167.255.255262,142
43168.168.0.0/14168.168.0.1 to 168.171.255.254168.171.255.255262,142
44168.172.0.0/14168.172.0.1 to 168.175.255.254168.175.255.255262,142
45168.176.0.0/14168.176.0.1 to 168.179.255.254168.179.255.255262,142
46168.180.0.0/14168.180.0.1 to 168.183.255.254168.183.255.255262,142
47168.184.0.0/14168.184.0.1 to 168.187.255.254168.187.255.255262,142
48168.188.0.0/14168.188.0.1 to 168.191.255.254168.191.255.255262,142
49168.192.0.0/14168.192.0.1 to 168.195.255.254168.195.255.255262,142
50168.196.0.0/14168.196.0.1 to 168.199.255.254168.199.255.255262,142
51168.200.0.0/14168.200.0.1 to 168.203.255.254168.203.255.255262,142
52168.204.0.0/14168.204.0.1 to 168.207.255.254168.207.255.255262,142
53168.208.0.0/14168.208.0.1 to 168.211.255.254168.211.255.255262,142
54168.212.0.0/14168.212.0.1 to 168.215.255.254168.215.255.255262,142
55168.216.0.0/14168.216.0.1 to 168.219.255.254168.219.255.255262,142
56168.220.0.0/14168.220.0.1 to 168.223.255.254168.223.255.255262,142
57168.224.0.0/14168.224.0.1 to 168.227.255.254168.227.255.255262,142
58168.228.0.0/14168.228.0.1 to 168.231.255.254168.231.255.255262,142
59168.232.0.0/14168.232.0.1 to 168.235.255.254168.235.255.255262,142
60168.236.0.0/14168.236.0.1 to 168.239.255.254168.239.255.255262,142
61168.240.0.0/14168.240.0.1 to 168.243.255.254168.243.255.255262,142
62168.244.0.0/14168.244.0.1 to 168.247.255.254168.247.255.255262,142
63168.248.0.0/14168.248.0.1 to 168.251.255.254168.251.255.255262,142
64168.252.0.0/14168.252.0.1 to 168.255.255.254168.255.255.255262,142
65169.0.0.0/14169.0.0.1 to 169.3.255.254169.3.255.255262,142
66169.4.0.0/14169.4.0.1 to 169.7.255.254169.7.255.255262,142
67169.8.0.0/14169.8.0.1 to 169.11.255.254169.11.255.255262,142
68169.12.0.0/14169.12.0.1 to 169.15.255.254169.15.255.255262,142
69169.16.0.0/14169.16.0.1 to 169.19.255.254169.19.255.255262,142
70169.20.0.0/14169.20.0.1 to 169.23.255.254169.23.255.255262,142
71169.24.0.0/14169.24.0.1 to 169.27.255.254169.27.255.255262,142
72169.28.0.0/14169.28.0.1 to 169.31.255.254169.31.255.255262,142
73169.32.0.0/14169.32.0.1 to 169.35.255.254169.35.255.255262,142
74169.36.0.0/14169.36.0.1 to 169.39.255.254169.39.255.255262,142
75169.40.0.0/14169.40.0.1 to 169.43.255.254169.43.255.255262,142
76169.44.0.0/14169.44.0.1 to 169.47.255.254169.47.255.255262,142
77169.48.0.0/14169.48.0.1 to 169.51.255.254169.51.255.255262,142
78169.52.0.0/14169.52.0.1 to 169.55.255.254169.55.255.255262,142
79169.56.0.0/14169.56.0.1 to 169.59.255.254169.59.255.255262,142
80169.60.0.0/14169.60.0.1 to 169.63.255.254169.63.255.255262,142
81169.64.0.0/14169.64.0.1 to 169.67.255.254169.67.255.255262,142
82169.68.0.0/14169.68.0.1 to 169.71.255.254169.71.255.255262,142
83169.72.0.0/14169.72.0.1 to 169.75.255.254169.75.255.255262,142
84169.76.0.0/14169.76.0.1 to 169.79.255.254169.79.255.255262,142
85169.80.0.0/14169.80.0.1 to 169.83.255.254169.83.255.255262,142
86169.84.0.0/14169.84.0.1 to 169.87.255.254169.87.255.255262,142
87169.88.0.0/14169.88.0.1 to 169.91.255.254169.91.255.255262,142
88169.92.0.0/14169.92.0.1 to 169.95.255.254169.95.255.255262,142
89169.96.0.0/14169.96.0.1 to 169.99.255.254169.99.255.255262,142
90169.100.0.0/14169.100.0.1 to 169.103.255.254169.103.255.255262,142
91169.104.0.0/14169.104.0.1 to 169.107.255.254169.107.255.255262,142
92169.108.0.0/14169.108.0.1 to 169.111.255.254169.111.255.255262,142
93169.112.0.0/14169.112.0.1 to 169.115.255.254169.115.255.255262,142
94169.116.0.0/14169.116.0.1 to 169.119.255.254169.119.255.255262,142
95169.120.0.0/14169.120.0.1 to 169.123.255.254169.123.255.255262,142
96169.124.0.0/14169.124.0.1 to 169.127.255.254169.127.255.255262,142
97169.128.0.0/14169.128.0.1 to 169.131.255.254169.131.255.255262,142
98169.132.0.0/14169.132.0.1 to 169.135.255.254169.135.255.255262,142
99169.136.0.0/14169.136.0.1 to 169.139.255.254169.139.255.255262,142
100169.140.0.0/14169.140.0.1 to 169.143.255.254169.143.255.255262,142
101169.144.0.0/14169.144.0.1 to 169.147.255.254169.147.255.255262,142
102169.148.0.0/14169.148.0.1 to 169.151.255.254169.151.255.255262,142
103169.152.0.0/14169.152.0.1 to 169.155.255.254169.155.255.255262,142
104169.156.0.0/14169.156.0.1 to 169.159.255.254169.159.255.255262,142
105169.160.0.0/14169.160.0.1 to 169.163.255.254169.163.255.255262,142
106169.164.0.0/14169.164.0.1 to 169.167.255.254169.167.255.255262,142
107169.168.0.0/14169.168.0.1 to 169.171.255.254169.171.255.255262,142
108169.172.0.0/14169.172.0.1 to 169.175.255.254169.175.255.255262,142
109169.176.0.0/14169.176.0.1 to 169.179.255.254169.179.255.255262,142
110169.180.0.0/14169.180.0.1 to 169.183.255.254169.183.255.255262,142
111169.184.0.0/14169.184.0.1 to 169.187.255.254169.187.255.255262,142
112169.188.0.0/14169.188.0.1 to 169.191.255.254169.191.255.255262,142
113169.192.0.0/14169.192.0.1 to 169.195.255.254169.195.255.255262,142
114169.196.0.0/14169.196.0.1 to 169.199.255.254169.199.255.255262,142
115169.200.0.0/14169.200.0.1 to 169.203.255.254169.203.255.255262,142
116169.204.0.0/14169.204.0.1 to 169.207.255.254169.207.255.255262,142
117169.208.0.0/14169.208.0.1 to 169.211.255.254169.211.255.255262,142
118169.212.0.0/14169.212.0.1 to 169.215.255.254169.215.255.255262,142
119169.216.0.0/14169.216.0.1 to 169.219.255.254169.219.255.255262,142
120169.220.0.0/14169.220.0.1 to 169.223.255.254169.223.255.255262,142
121169.224.0.0/14169.224.0.1 to 169.227.255.254169.227.255.255262,142
122169.228.0.0/14169.228.0.1 to 169.231.255.254169.231.255.255262,142
123169.232.0.0/14169.232.0.1 to 169.235.255.254169.235.255.255262,142
124169.236.0.0/14169.236.0.1 to 169.239.255.254169.239.255.255262,142
125169.240.0.0/14169.240.0.1 to 169.243.255.254169.243.255.255262,142
126169.244.0.0/14169.244.0.1 to 169.247.255.254169.247.255.255262,142
127169.248.0.0/14169.248.0.1 to 169.251.255.254169.251.255.255262,142
128169.252.0.0/14169.252.0.1 to 169.255.255.254169.255.255.255262,142
129170.0.0.0/14170.0.0.1 to 170.3.255.254170.3.255.255262,142
130170.4.0.0/14170.4.0.1 to 170.7.255.254170.7.255.255262,142
131170.8.0.0/14170.8.0.1 to 170.11.255.254170.11.255.255262,142
132170.12.0.0/14170.12.0.1 to 170.15.255.254170.15.255.255262,142
133170.16.0.0/14170.16.0.1 to 170.19.255.254170.19.255.255262,142
134170.20.0.0/14170.20.0.1 to 170.23.255.254170.23.255.255262,142
135170.24.0.0/14170.24.0.1 to 170.27.255.254170.27.255.255262,142
136170.28.0.0/14170.28.0.1 to 170.31.255.254170.31.255.255262,142
137170.32.0.0/14170.32.0.1 to 170.35.255.254170.35.255.255262,142
138170.36.0.0/14170.36.0.1 to 170.39.255.254170.39.255.255262,142
139170.40.0.0/14170.40.0.1 to 170.43.255.254170.43.255.255262,142
140170.44.0.0/14170.44.0.1 to 170.47.255.254170.47.255.255262,142
141170.48.0.0/14170.48.0.1 to 170.51.255.254170.51.255.255262,142
142170.52.0.0/14170.52.0.1 to 170.55.255.254170.55.255.255262,142
143170.56.0.0/14170.56.0.1 to 170.59.255.254170.59.255.255262,142
144170.60.0.0/14170.60.0.1 to 170.63.255.254170.63.255.255262,142
145170.64.0.0/14170.64.0.1 to 170.67.255.254170.67.255.255262,142
146170.68.0.0/14170.68.0.1 to 170.71.255.254170.71.255.255262,142
147170.72.0.0/14170.72.0.1 to 170.75.255.254170.75.255.255262,142
148170.76.0.0/14170.76.0.1 to 170.79.255.254170.79.255.255262,142
149170.80.0.0/14170.80.0.1 to 170.83.255.254170.83.255.255262,142
150170.84.0.0/14170.84.0.1 to 170.87.255.254170.87.255.255262,142
151170.88.0.0/14170.88.0.1 to 170.91.255.254170.91.255.255262,142
152170.92.0.0/14170.92.0.1 to 170.95.255.254170.95.255.255262,142
153170.96.0.0/14170.96.0.1 to 170.99.255.254170.99.255.255262,142
154170.100.0.0/14170.100.0.1 to 170.103.255.254170.103.255.255262,142
155170.104.0.0/14170.104.0.1 to 170.107.255.254170.107.255.255262,142
156170.108.0.0/14170.108.0.1 to 170.111.255.254170.111.255.255262,142
157170.112.0.0/14170.112.0.1 to 170.115.255.254170.115.255.255262,142
158170.116.0.0/14170.116.0.1 to 170.119.255.254170.119.255.255262,142
159170.120.0.0/14170.120.0.1 to 170.123.255.254170.123.255.255262,142
160170.124.0.0/14170.124.0.1 to 170.127.255.254170.127.255.255262,142
161170.128.0.0/14170.128.0.1 to 170.131.255.254170.131.255.255262,142
162170.132.0.0/14170.132.0.1 to 170.135.255.254170.135.255.255262,142
163170.136.0.0/14170.136.0.1 to 170.139.255.254170.139.255.255262,142
164170.140.0.0/14170.140.0.1 to 170.143.255.254170.143.255.255262,142
165170.144.0.0/14170.144.0.1 to 170.147.255.254170.147.255.255262,142
166170.148.0.0/14170.148.0.1 to 170.151.255.254170.151.255.255262,142
167170.152.0.0/14170.152.0.1 to 170.155.255.254170.155.255.255262,142
168170.156.0.0/14170.156.0.1 to 170.159.255.254170.159.255.255262,142
169170.160.0.0/14170.160.0.1 to 170.163.255.254170.163.255.255262,142
170170.164.0.0/14170.164.0.1 to 170.167.255.254170.167.255.255262,142
171170.168.0.0/14170.168.0.1 to 170.171.255.254170.171.255.255262,142
172170.172.0.0/14170.172.0.1 to 170.175.255.254170.175.255.255262,142
173170.176.0.0/14170.176.0.1 to 170.179.255.254170.179.255.255262,142
174170.180.0.0/14170.180.0.1 to 170.183.255.254170.183.255.255262,142
175170.184.0.0/14170.184.0.1 to 170.187.255.254170.187.255.255262,142
176170.188.0.0/14170.188.0.1 to 170.191.255.254170.191.255.255262,142
177170.192.0.0/14170.192.0.1 to 170.195.255.254170.195.255.255262,142
178170.196.0.0/14170.196.0.1 to 170.199.255.254170.199.255.255262,142
179170.200.0.0/14170.200.0.1 to 170.203.255.254170.203.255.255262,142
180170.204.0.0/14170.204.0.1 to 170.207.255.254170.207.255.255262,142
181170.208.0.0/14170.208.0.1 to 170.211.255.254170.211.255.255262,142
182170.212.0.0/14170.212.0.1 to 170.215.255.254170.215.255.255262,142
183170.216.0.0/14170.216.0.1 to 170.219.255.254170.219.255.255262,142
184170.220.0.0/14170.220.0.1 to 170.223.255.254170.223.255.255262,142
185170.224.0.0/14170.224.0.1 to 170.227.255.254170.227.255.255262,142
186170.228.0.0/14170.228.0.1 to 170.231.255.254170.231.255.255262,142
187170.232.0.0/14170.232.0.1 to 170.235.255.254170.235.255.255262,142
188170.236.0.0/14170.236.0.1 to 170.239.255.254170.239.255.255262,142
189170.240.0.0/14170.240.0.1 to 170.243.255.254170.243.255.255262,142
190170.244.0.0/14170.244.0.1 to 170.247.255.254170.247.255.255262,142
191170.248.0.0/14170.248.0.1 to 170.251.255.254170.251.255.255262,142
192170.252.0.0/14170.252.0.1 to 170.255.255.254170.255.255.255262,142
193171.0.0.0/14171.0.0.1 to 171.3.255.254171.3.255.255262,142
194171.4.0.0/14171.4.0.1 to 171.7.255.254171.7.255.255262,142
195171.8.0.0/14171.8.0.1 to 171.11.255.254171.11.255.255262,142
196171.12.0.0/14171.12.0.1 to 171.15.255.254171.15.255.255262,142
197171.16.0.0/14171.16.0.1 to 171.19.255.254171.19.255.255262,142
198171.20.0.0/14171.20.0.1 to 171.23.255.254171.23.255.255262,142
199171.24.0.0/14171.24.0.1 to 171.27.255.254171.27.255.255262,142
200171.28.0.0/14171.28.0.1 to 171.31.255.254171.31.255.255262,142
201171.32.0.0/14171.32.0.1 to 171.35.255.254171.35.255.255262,142
202171.36.0.0/14171.36.0.1 to 171.39.255.254171.39.255.255262,142
203171.40.0.0/14171.40.0.1 to 171.43.255.254171.43.255.255262,142
204171.44.0.0/14171.44.0.1 to 171.47.255.254171.47.255.255262,142
205171.48.0.0/14171.48.0.1 to 171.51.255.254171.51.255.255262,142
206171.52.0.0/14171.52.0.1 to 171.55.255.254171.55.255.255262,142
207171.56.0.0/14171.56.0.1 to 171.59.255.254171.59.255.255262,142
208171.60.0.0/14171.60.0.1 to 171.63.255.254171.63.255.255262,142
209171.64.0.0/14171.64.0.1 to 171.67.255.254171.67.255.255262,142
210171.68.0.0/14171.68.0.1 to 171.71.255.254171.71.255.255262,142
211171.72.0.0/14171.72.0.1 to 171.75.255.254171.75.255.255262,142
212171.76.0.0/14171.76.0.1 to 171.79.255.254171.79.255.255262,142
213171.80.0.0/14171.80.0.1 to 171.83.255.254171.83.255.255262,142
214171.84.0.0/14171.84.0.1 to 171.87.255.254171.87.255.255262,142
215171.88.0.0/14171.88.0.1 to 171.91.255.254171.91.255.255262,142
216171.92.0.0/14171.92.0.1 to 171.95.255.254171.95.255.255262,142
217171.96.0.0/14171.96.0.1 to 171.99.255.254171.99.255.255262,142
218171.100.0.0/14171.100.0.1 to 171.103.255.254171.103.255.255262,142
219171.104.0.0/14171.104.0.1 to 171.107.255.254171.107.255.255262,142
220171.108.0.0/14171.108.0.1 to 171.111.255.254171.111.255.255262,142
221171.112.0.0/14171.112.0.1 to 171.115.255.254171.115.255.255262,142
222171.116.0.0/14171.116.0.1 to 171.119.255.254171.119.255.255262,142
223171.120.0.0/14171.120.0.1 to 171.123.255.254171.123.255.255262,142
224171.124.0.0/14171.124.0.1 to 171.127.255.254171.127.255.255262,142
225171.128.0.0/14171.128.0.1 to 171.131.255.254171.131.255.255262,142
226171.132.0.0/14171.132.0.1 to 171.135.255.254171.135.255.255262,142
227171.136.0.0/14171.136.0.1 to 171.139.255.254171.139.255.255262,142
228171.140.0.0/14171.140.0.1 to 171.143.255.254171.143.255.255262,142
229171.144.0.0/14171.144.0.1 to 171.147.255.254171.147.255.255262,142
230171.148.0.0/14171.148.0.1 to 171.151.255.254171.151.255.255262,142
231171.152.0.0/14171.152.0.1 to 171.155.255.254171.155.255.255262,142
232171.156.0.0/14171.156.0.1 to 171.159.255.254171.159.255.255262,142
233171.160.0.0/14171.160.0.1 to 171.163.255.254171.163.255.255262,142
234171.164.0.0/14171.164.0.1 to 171.167.255.254171.167.255.255262,142
235171.168.0.0/14171.168.0.1 to 171.171.255.254171.171.255.255262,142
236171.172.0.0/14171.172.0.1 to 171.175.255.254171.175.255.255262,142
237171.176.0.0/14171.176.0.1 to 171.179.255.254171.179.255.255262,142
238171.180.0.0/14171.180.0.1 to 171.183.255.254171.183.255.255262,142
239171.184.0.0/14171.184.0.1 to 171.187.255.254171.187.255.255262,142
240171.188.0.0/14171.188.0.1 to 171.191.255.254171.191.255.255262,142
241171.192.0.0/14171.192.0.1 to 171.195.255.254171.195.255.255262,142
242171.196.0.0/14171.196.0.1 to 171.199.255.254171.199.255.255262,142
243171.200.0.0/14171.200.0.1 to 171.203.255.254171.203.255.255262,142
244171.204.0.0/14171.204.0.1 to 171.207.255.254171.207.255.255262,142
245171.208.0.0/14171.208.0.1 to 171.211.255.254171.211.255.255262,142
246171.212.0.0/14171.212.0.1 to 171.215.255.254171.215.255.255262,142
247171.216.0.0/14171.216.0.1 to 171.219.255.254171.219.255.255262,142
248171.220.0.0/14171.220.0.1 to 171.223.255.254171.223.255.255262,142
249171.224.0.0/14171.224.0.1 to 171.227.255.254171.227.255.255262,142
250171.228.0.0/14171.228.0.1 to 171.231.255.254171.231.255.255262,142
251171.232.0.0/14171.232.0.1 to 171.235.255.254171.235.255.255262,142
252171.236.0.0/14171.236.0.1 to 171.239.255.254171.239.255.255262,142
253171.240.0.0/14171.240.0.1 to 171.243.255.254171.243.255.255262,142
254171.244.0.0/14171.244.0.1 to 171.247.255.254171.247.255.255262,142
255171.248.0.0/14171.248.0.1 to 171.251.255.254171.251.255.255262,142
256171.252.0.0/14171.252.0.1 to 171.255.255.254171.255.255.255262,142

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.