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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.

Network127.0.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
127.0.0.0
Broadcast address
127.63.255.255
First usable
127.0.0.1
Last usable
127.63.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Loopback 127.0.0.0/8
This computer
Old class
A (default /8)
As numbers
Hex 7F000000 · Integer 2130706432 to 2134900735
Reverse DNS zones
0.127.in-addr.arpa
1.127.in-addr.arpa
2.127.in-addr.arpa
3.127.in-addr.arpa
4.127.in-addr.arpa
5.127.in-addr.arpa
6.127.in-addr.arpa
7.127.in-addr.arpa
8.127.in-addr.arpa
9.127.in-addr.arpa
10.127.in-addr.arpa
11.127.in-addr.arpa
12.127.in-addr.arpa
13.127.in-addr.arpa
14.127.in-addr.arpa
15.127.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01111111.00000000.00000000.00000000127.0.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network01111111.00000000.00000000.00000000127.0.0.0
Broadcast01111111.00111111.11111111.11111111127.63.255.255
Split into smaller subnets/22
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

127.0.0.0/10 makes 4,096 subnets of /22; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1127.0.0.0/22127.0.0.1 to 127.0.3.254127.0.3.2551,022
2127.0.4.0/22127.0.4.1 to 127.0.7.254127.0.7.2551,022
3127.0.8.0/22127.0.8.1 to 127.0.11.254127.0.11.2551,022
4127.0.12.0/22127.0.12.1 to 127.0.15.254127.0.15.2551,022
5127.0.16.0/22127.0.16.1 to 127.0.19.254127.0.19.2551,022
6127.0.20.0/22127.0.20.1 to 127.0.23.254127.0.23.2551,022
7127.0.24.0/22127.0.24.1 to 127.0.27.254127.0.27.2551,022
8127.0.28.0/22127.0.28.1 to 127.0.31.254127.0.31.2551,022
9127.0.32.0/22127.0.32.1 to 127.0.35.254127.0.35.2551,022
10127.0.36.0/22127.0.36.1 to 127.0.39.254127.0.39.2551,022
11127.0.40.0/22127.0.40.1 to 127.0.43.254127.0.43.2551,022
12127.0.44.0/22127.0.44.1 to 127.0.47.254127.0.47.2551,022
13127.0.48.0/22127.0.48.1 to 127.0.51.254127.0.51.2551,022
14127.0.52.0/22127.0.52.1 to 127.0.55.254127.0.55.2551,022
15127.0.56.0/22127.0.56.1 to 127.0.59.254127.0.59.2551,022
16127.0.60.0/22127.0.60.1 to 127.0.63.254127.0.63.2551,022
17127.0.64.0/22127.0.64.1 to 127.0.67.254127.0.67.2551,022
18127.0.68.0/22127.0.68.1 to 127.0.71.254127.0.71.2551,022
19127.0.72.0/22127.0.72.1 to 127.0.75.254127.0.75.2551,022
20127.0.76.0/22127.0.76.1 to 127.0.79.254127.0.79.2551,022
21127.0.80.0/22127.0.80.1 to 127.0.83.254127.0.83.2551,022
22127.0.84.0/22127.0.84.1 to 127.0.87.254127.0.87.2551,022
23127.0.88.0/22127.0.88.1 to 127.0.91.254127.0.91.2551,022
24127.0.92.0/22127.0.92.1 to 127.0.95.254127.0.95.2551,022
25127.0.96.0/22127.0.96.1 to 127.0.99.254127.0.99.2551,022
26127.0.100.0/22127.0.100.1 to 127.0.103.254127.0.103.2551,022
27127.0.104.0/22127.0.104.1 to 127.0.107.254127.0.107.2551,022
28127.0.108.0/22127.0.108.1 to 127.0.111.254127.0.111.2551,022
29127.0.112.0/22127.0.112.1 to 127.0.115.254127.0.115.2551,022
30127.0.116.0/22127.0.116.1 to 127.0.119.254127.0.119.2551,022
31127.0.120.0/22127.0.120.1 to 127.0.123.254127.0.123.2551,022
32127.0.124.0/22127.0.124.1 to 127.0.127.254127.0.127.2551,022
33127.0.128.0/22127.0.128.1 to 127.0.131.254127.0.131.2551,022
34127.0.132.0/22127.0.132.1 to 127.0.135.254127.0.135.2551,022
35127.0.136.0/22127.0.136.1 to 127.0.139.254127.0.139.2551,022
36127.0.140.0/22127.0.140.1 to 127.0.143.254127.0.143.2551,022
37127.0.144.0/22127.0.144.1 to 127.0.147.254127.0.147.2551,022
38127.0.148.0/22127.0.148.1 to 127.0.151.254127.0.151.2551,022
39127.0.152.0/22127.0.152.1 to 127.0.155.254127.0.155.2551,022
40127.0.156.0/22127.0.156.1 to 127.0.159.254127.0.159.2551,022
41127.0.160.0/22127.0.160.1 to 127.0.163.254127.0.163.2551,022
42127.0.164.0/22127.0.164.1 to 127.0.167.254127.0.167.2551,022
43127.0.168.0/22127.0.168.1 to 127.0.171.254127.0.171.2551,022
44127.0.172.0/22127.0.172.1 to 127.0.175.254127.0.175.2551,022
45127.0.176.0/22127.0.176.1 to 127.0.179.254127.0.179.2551,022
46127.0.180.0/22127.0.180.1 to 127.0.183.254127.0.183.2551,022
47127.0.184.0/22127.0.184.1 to 127.0.187.254127.0.187.2551,022
48127.0.188.0/22127.0.188.1 to 127.0.191.254127.0.191.2551,022
49127.0.192.0/22127.0.192.1 to 127.0.195.254127.0.195.2551,022
50127.0.196.0/22127.0.196.1 to 127.0.199.254127.0.199.2551,022
51127.0.200.0/22127.0.200.1 to 127.0.203.254127.0.203.2551,022
52127.0.204.0/22127.0.204.1 to 127.0.207.254127.0.207.2551,022
53127.0.208.0/22127.0.208.1 to 127.0.211.254127.0.211.2551,022
54127.0.212.0/22127.0.212.1 to 127.0.215.254127.0.215.2551,022
55127.0.216.0/22127.0.216.1 to 127.0.219.254127.0.219.2551,022
56127.0.220.0/22127.0.220.1 to 127.0.223.254127.0.223.2551,022
57127.0.224.0/22127.0.224.1 to 127.0.227.254127.0.227.2551,022
58127.0.228.0/22127.0.228.1 to 127.0.231.254127.0.231.2551,022
59127.0.232.0/22127.0.232.1 to 127.0.235.254127.0.235.2551,022
60127.0.236.0/22127.0.236.1 to 127.0.239.254127.0.239.2551,022
61127.0.240.0/22127.0.240.1 to 127.0.243.254127.0.243.2551,022
62127.0.244.0/22127.0.244.1 to 127.0.247.254127.0.247.2551,022
63127.0.248.0/22127.0.248.1 to 127.0.251.254127.0.251.2551,022
64127.0.252.0/22127.0.252.1 to 127.0.255.254127.0.255.2551,022
65127.1.0.0/22127.1.0.1 to 127.1.3.254127.1.3.2551,022
66127.1.4.0/22127.1.4.1 to 127.1.7.254127.1.7.2551,022
67127.1.8.0/22127.1.8.1 to 127.1.11.254127.1.11.2551,022
68127.1.12.0/22127.1.12.1 to 127.1.15.254127.1.15.2551,022
69127.1.16.0/22127.1.16.1 to 127.1.19.254127.1.19.2551,022
70127.1.20.0/22127.1.20.1 to 127.1.23.254127.1.23.2551,022
71127.1.24.0/22127.1.24.1 to 127.1.27.254127.1.27.2551,022
72127.1.28.0/22127.1.28.1 to 127.1.31.254127.1.31.2551,022
73127.1.32.0/22127.1.32.1 to 127.1.35.254127.1.35.2551,022
74127.1.36.0/22127.1.36.1 to 127.1.39.254127.1.39.2551,022
75127.1.40.0/22127.1.40.1 to 127.1.43.254127.1.43.2551,022
76127.1.44.0/22127.1.44.1 to 127.1.47.254127.1.47.2551,022
77127.1.48.0/22127.1.48.1 to 127.1.51.254127.1.51.2551,022
78127.1.52.0/22127.1.52.1 to 127.1.55.254127.1.55.2551,022
79127.1.56.0/22127.1.56.1 to 127.1.59.254127.1.59.2551,022
80127.1.60.0/22127.1.60.1 to 127.1.63.254127.1.63.2551,022
81127.1.64.0/22127.1.64.1 to 127.1.67.254127.1.67.2551,022
82127.1.68.0/22127.1.68.1 to 127.1.71.254127.1.71.2551,022
83127.1.72.0/22127.1.72.1 to 127.1.75.254127.1.75.2551,022
84127.1.76.0/22127.1.76.1 to 127.1.79.254127.1.79.2551,022
85127.1.80.0/22127.1.80.1 to 127.1.83.254127.1.83.2551,022
86127.1.84.0/22127.1.84.1 to 127.1.87.254127.1.87.2551,022
87127.1.88.0/22127.1.88.1 to 127.1.91.254127.1.91.2551,022
88127.1.92.0/22127.1.92.1 to 127.1.95.254127.1.95.2551,022
89127.1.96.0/22127.1.96.1 to 127.1.99.254127.1.99.2551,022
90127.1.100.0/22127.1.100.1 to 127.1.103.254127.1.103.2551,022
91127.1.104.0/22127.1.104.1 to 127.1.107.254127.1.107.2551,022
92127.1.108.0/22127.1.108.1 to 127.1.111.254127.1.111.2551,022
93127.1.112.0/22127.1.112.1 to 127.1.115.254127.1.115.2551,022
94127.1.116.0/22127.1.116.1 to 127.1.119.254127.1.119.2551,022
95127.1.120.0/22127.1.120.1 to 127.1.123.254127.1.123.2551,022
96127.1.124.0/22127.1.124.1 to 127.1.127.254127.1.127.2551,022
97127.1.128.0/22127.1.128.1 to 127.1.131.254127.1.131.2551,022
98127.1.132.0/22127.1.132.1 to 127.1.135.254127.1.135.2551,022
99127.1.136.0/22127.1.136.1 to 127.1.139.254127.1.139.2551,022
100127.1.140.0/22127.1.140.1 to 127.1.143.254127.1.143.2551,022
101127.1.144.0/22127.1.144.1 to 127.1.147.254127.1.147.2551,022
102127.1.148.0/22127.1.148.1 to 127.1.151.254127.1.151.2551,022
103127.1.152.0/22127.1.152.1 to 127.1.155.254127.1.155.2551,022
104127.1.156.0/22127.1.156.1 to 127.1.159.254127.1.159.2551,022
105127.1.160.0/22127.1.160.1 to 127.1.163.254127.1.163.2551,022
106127.1.164.0/22127.1.164.1 to 127.1.167.254127.1.167.2551,022
107127.1.168.0/22127.1.168.1 to 127.1.171.254127.1.171.2551,022
108127.1.172.0/22127.1.172.1 to 127.1.175.254127.1.175.2551,022
109127.1.176.0/22127.1.176.1 to 127.1.179.254127.1.179.2551,022
110127.1.180.0/22127.1.180.1 to 127.1.183.254127.1.183.2551,022
111127.1.184.0/22127.1.184.1 to 127.1.187.254127.1.187.2551,022
112127.1.188.0/22127.1.188.1 to 127.1.191.254127.1.191.2551,022
113127.1.192.0/22127.1.192.1 to 127.1.195.254127.1.195.2551,022
114127.1.196.0/22127.1.196.1 to 127.1.199.254127.1.199.2551,022
115127.1.200.0/22127.1.200.1 to 127.1.203.254127.1.203.2551,022
116127.1.204.0/22127.1.204.1 to 127.1.207.254127.1.207.2551,022
117127.1.208.0/22127.1.208.1 to 127.1.211.254127.1.211.2551,022
118127.1.212.0/22127.1.212.1 to 127.1.215.254127.1.215.2551,022
119127.1.216.0/22127.1.216.1 to 127.1.219.254127.1.219.2551,022
120127.1.220.0/22127.1.220.1 to 127.1.223.254127.1.223.2551,022
121127.1.224.0/22127.1.224.1 to 127.1.227.254127.1.227.2551,022
122127.1.228.0/22127.1.228.1 to 127.1.231.254127.1.231.2551,022
123127.1.232.0/22127.1.232.1 to 127.1.235.254127.1.235.2551,022
124127.1.236.0/22127.1.236.1 to 127.1.239.254127.1.239.2551,022
125127.1.240.0/22127.1.240.1 to 127.1.243.254127.1.243.2551,022
126127.1.244.0/22127.1.244.1 to 127.1.247.254127.1.247.2551,022
127127.1.248.0/22127.1.248.1 to 127.1.251.254127.1.251.2551,022
128127.1.252.0/22127.1.252.1 to 127.1.255.254127.1.255.2551,022
129127.2.0.0/22127.2.0.1 to 127.2.3.254127.2.3.2551,022
130127.2.4.0/22127.2.4.1 to 127.2.7.254127.2.7.2551,022
131127.2.8.0/22127.2.8.1 to 127.2.11.254127.2.11.2551,022
132127.2.12.0/22127.2.12.1 to 127.2.15.254127.2.15.2551,022
133127.2.16.0/22127.2.16.1 to 127.2.19.254127.2.19.2551,022
134127.2.20.0/22127.2.20.1 to 127.2.23.254127.2.23.2551,022
135127.2.24.0/22127.2.24.1 to 127.2.27.254127.2.27.2551,022
136127.2.28.0/22127.2.28.1 to 127.2.31.254127.2.31.2551,022
137127.2.32.0/22127.2.32.1 to 127.2.35.254127.2.35.2551,022
138127.2.36.0/22127.2.36.1 to 127.2.39.254127.2.39.2551,022
139127.2.40.0/22127.2.40.1 to 127.2.43.254127.2.43.2551,022
140127.2.44.0/22127.2.44.1 to 127.2.47.254127.2.47.2551,022
141127.2.48.0/22127.2.48.1 to 127.2.51.254127.2.51.2551,022
142127.2.52.0/22127.2.52.1 to 127.2.55.254127.2.55.2551,022
143127.2.56.0/22127.2.56.1 to 127.2.59.254127.2.59.2551,022
144127.2.60.0/22127.2.60.1 to 127.2.63.254127.2.63.2551,022
145127.2.64.0/22127.2.64.1 to 127.2.67.254127.2.67.2551,022
146127.2.68.0/22127.2.68.1 to 127.2.71.254127.2.71.2551,022
147127.2.72.0/22127.2.72.1 to 127.2.75.254127.2.75.2551,022
148127.2.76.0/22127.2.76.1 to 127.2.79.254127.2.79.2551,022
149127.2.80.0/22127.2.80.1 to 127.2.83.254127.2.83.2551,022
150127.2.84.0/22127.2.84.1 to 127.2.87.254127.2.87.2551,022
151127.2.88.0/22127.2.88.1 to 127.2.91.254127.2.91.2551,022
152127.2.92.0/22127.2.92.1 to 127.2.95.254127.2.95.2551,022
153127.2.96.0/22127.2.96.1 to 127.2.99.254127.2.99.2551,022
154127.2.100.0/22127.2.100.1 to 127.2.103.254127.2.103.2551,022
155127.2.104.0/22127.2.104.1 to 127.2.107.254127.2.107.2551,022
156127.2.108.0/22127.2.108.1 to 127.2.111.254127.2.111.2551,022
157127.2.112.0/22127.2.112.1 to 127.2.115.254127.2.115.2551,022
158127.2.116.0/22127.2.116.1 to 127.2.119.254127.2.119.2551,022
159127.2.120.0/22127.2.120.1 to 127.2.123.254127.2.123.2551,022
160127.2.124.0/22127.2.124.1 to 127.2.127.254127.2.127.2551,022
161127.2.128.0/22127.2.128.1 to 127.2.131.254127.2.131.2551,022
162127.2.132.0/22127.2.132.1 to 127.2.135.254127.2.135.2551,022
163127.2.136.0/22127.2.136.1 to 127.2.139.254127.2.139.2551,022
164127.2.140.0/22127.2.140.1 to 127.2.143.254127.2.143.2551,022
165127.2.144.0/22127.2.144.1 to 127.2.147.254127.2.147.2551,022
166127.2.148.0/22127.2.148.1 to 127.2.151.254127.2.151.2551,022
167127.2.152.0/22127.2.152.1 to 127.2.155.254127.2.155.2551,022
168127.2.156.0/22127.2.156.1 to 127.2.159.254127.2.159.2551,022
169127.2.160.0/22127.2.160.1 to 127.2.163.254127.2.163.2551,022
170127.2.164.0/22127.2.164.1 to 127.2.167.254127.2.167.2551,022
171127.2.168.0/22127.2.168.1 to 127.2.171.254127.2.171.2551,022
172127.2.172.0/22127.2.172.1 to 127.2.175.254127.2.175.2551,022
173127.2.176.0/22127.2.176.1 to 127.2.179.254127.2.179.2551,022
174127.2.180.0/22127.2.180.1 to 127.2.183.254127.2.183.2551,022
175127.2.184.0/22127.2.184.1 to 127.2.187.254127.2.187.2551,022
176127.2.188.0/22127.2.188.1 to 127.2.191.254127.2.191.2551,022
177127.2.192.0/22127.2.192.1 to 127.2.195.254127.2.195.2551,022
178127.2.196.0/22127.2.196.1 to 127.2.199.254127.2.199.2551,022
179127.2.200.0/22127.2.200.1 to 127.2.203.254127.2.203.2551,022
180127.2.204.0/22127.2.204.1 to 127.2.207.254127.2.207.2551,022
181127.2.208.0/22127.2.208.1 to 127.2.211.254127.2.211.2551,022
182127.2.212.0/22127.2.212.1 to 127.2.215.254127.2.215.2551,022
183127.2.216.0/22127.2.216.1 to 127.2.219.254127.2.219.2551,022
184127.2.220.0/22127.2.220.1 to 127.2.223.254127.2.223.2551,022
185127.2.224.0/22127.2.224.1 to 127.2.227.254127.2.227.2551,022
186127.2.228.0/22127.2.228.1 to 127.2.231.254127.2.231.2551,022
187127.2.232.0/22127.2.232.1 to 127.2.235.254127.2.235.2551,022
188127.2.236.0/22127.2.236.1 to 127.2.239.254127.2.239.2551,022
189127.2.240.0/22127.2.240.1 to 127.2.243.254127.2.243.2551,022
190127.2.244.0/22127.2.244.1 to 127.2.247.254127.2.247.2551,022
191127.2.248.0/22127.2.248.1 to 127.2.251.254127.2.251.2551,022
192127.2.252.0/22127.2.252.1 to 127.2.255.254127.2.255.2551,022
193127.3.0.0/22127.3.0.1 to 127.3.3.254127.3.3.2551,022
194127.3.4.0/22127.3.4.1 to 127.3.7.254127.3.7.2551,022
195127.3.8.0/22127.3.8.1 to 127.3.11.254127.3.11.2551,022
196127.3.12.0/22127.3.12.1 to 127.3.15.254127.3.15.2551,022
197127.3.16.0/22127.3.16.1 to 127.3.19.254127.3.19.2551,022
198127.3.20.0/22127.3.20.1 to 127.3.23.254127.3.23.2551,022
199127.3.24.0/22127.3.24.1 to 127.3.27.254127.3.27.2551,022
200127.3.28.0/22127.3.28.1 to 127.3.31.254127.3.31.2551,022
201127.3.32.0/22127.3.32.1 to 127.3.35.254127.3.35.2551,022
202127.3.36.0/22127.3.36.1 to 127.3.39.254127.3.39.2551,022
203127.3.40.0/22127.3.40.1 to 127.3.43.254127.3.43.2551,022
204127.3.44.0/22127.3.44.1 to 127.3.47.254127.3.47.2551,022
205127.3.48.0/22127.3.48.1 to 127.3.51.254127.3.51.2551,022
206127.3.52.0/22127.3.52.1 to 127.3.55.254127.3.55.2551,022
207127.3.56.0/22127.3.56.1 to 127.3.59.254127.3.59.2551,022
208127.3.60.0/22127.3.60.1 to 127.3.63.254127.3.63.2551,022
209127.3.64.0/22127.3.64.1 to 127.3.67.254127.3.67.2551,022
210127.3.68.0/22127.3.68.1 to 127.3.71.254127.3.71.2551,022
211127.3.72.0/22127.3.72.1 to 127.3.75.254127.3.75.2551,022
212127.3.76.0/22127.3.76.1 to 127.3.79.254127.3.79.2551,022
213127.3.80.0/22127.3.80.1 to 127.3.83.254127.3.83.2551,022
214127.3.84.0/22127.3.84.1 to 127.3.87.254127.3.87.2551,022
215127.3.88.0/22127.3.88.1 to 127.3.91.254127.3.91.2551,022
216127.3.92.0/22127.3.92.1 to 127.3.95.254127.3.95.2551,022
217127.3.96.0/22127.3.96.1 to 127.3.99.254127.3.99.2551,022
218127.3.100.0/22127.3.100.1 to 127.3.103.254127.3.103.2551,022
219127.3.104.0/22127.3.104.1 to 127.3.107.254127.3.107.2551,022
220127.3.108.0/22127.3.108.1 to 127.3.111.254127.3.111.2551,022
221127.3.112.0/22127.3.112.1 to 127.3.115.254127.3.115.2551,022
222127.3.116.0/22127.3.116.1 to 127.3.119.254127.3.119.2551,022
223127.3.120.0/22127.3.120.1 to 127.3.123.254127.3.123.2551,022
224127.3.124.0/22127.3.124.1 to 127.3.127.254127.3.127.2551,022
225127.3.128.0/22127.3.128.1 to 127.3.131.254127.3.131.2551,022
226127.3.132.0/22127.3.132.1 to 127.3.135.254127.3.135.2551,022
227127.3.136.0/22127.3.136.1 to 127.3.139.254127.3.139.2551,022
228127.3.140.0/22127.3.140.1 to 127.3.143.254127.3.143.2551,022
229127.3.144.0/22127.3.144.1 to 127.3.147.254127.3.147.2551,022
230127.3.148.0/22127.3.148.1 to 127.3.151.254127.3.151.2551,022
231127.3.152.0/22127.3.152.1 to 127.3.155.254127.3.155.2551,022
232127.3.156.0/22127.3.156.1 to 127.3.159.254127.3.159.2551,022
233127.3.160.0/22127.3.160.1 to 127.3.163.254127.3.163.2551,022
234127.3.164.0/22127.3.164.1 to 127.3.167.254127.3.167.2551,022
235127.3.168.0/22127.3.168.1 to 127.3.171.254127.3.171.2551,022
236127.3.172.0/22127.3.172.1 to 127.3.175.254127.3.175.2551,022
237127.3.176.0/22127.3.176.1 to 127.3.179.254127.3.179.2551,022
238127.3.180.0/22127.3.180.1 to 127.3.183.254127.3.183.2551,022
239127.3.184.0/22127.3.184.1 to 127.3.187.254127.3.187.2551,022
240127.3.188.0/22127.3.188.1 to 127.3.191.254127.3.191.2551,022
241127.3.192.0/22127.3.192.1 to 127.3.195.254127.3.195.2551,022
242127.3.196.0/22127.3.196.1 to 127.3.199.254127.3.199.2551,022
243127.3.200.0/22127.3.200.1 to 127.3.203.254127.3.203.2551,022
244127.3.204.0/22127.3.204.1 to 127.3.207.254127.3.207.2551,022
245127.3.208.0/22127.3.208.1 to 127.3.211.254127.3.211.2551,022
246127.3.212.0/22127.3.212.1 to 127.3.215.254127.3.215.2551,022
247127.3.216.0/22127.3.216.1 to 127.3.219.254127.3.219.2551,022
248127.3.220.0/22127.3.220.1 to 127.3.223.254127.3.223.2551,022
249127.3.224.0/22127.3.224.1 to 127.3.227.254127.3.227.2551,022
250127.3.228.0/22127.3.228.1 to 127.3.231.254127.3.231.2551,022
251127.3.232.0/22127.3.232.1 to 127.3.235.254127.3.235.2551,022
252127.3.236.0/22127.3.236.1 to 127.3.239.254127.3.239.2551,022
253127.3.240.0/22127.3.240.1 to 127.3.243.254127.3.243.2551,022
254127.3.244.0/22127.3.244.1 to 127.3.247.254127.3.247.2551,022
255127.3.248.0/22127.3.248.1 to 127.3.251.254127.3.251.2551,022
256127.3.252.0/22127.3.252.1 to 127.3.255.254127.3.255.2551,022

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.