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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.

Network127.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
127.0.0.0
Broadcast address
127.255.255.255
First usable
127.0.0.1
Last usable
127.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Loopback 127.0.0.0/8
This computer
Old class
A (default /8)
As numbers
Hex 7F000000 · Integer 2130706432 to 2147483647
Reverse DNS zone
127.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01111111..00000000.00000000.00000000127.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network01111111..00000000.00000000.00000000127.0.0.0
Broadcast01111111..11111111.11111111.11111111127.255.255.255
Split into smaller subnets/16
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

127.0.0.0/8 makes 256 subnets of /16.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1127.0.0.0/16127.0.0.1 to 127.0.255.254127.0.255.25565,534
2127.1.0.0/16127.1.0.1 to 127.1.255.254127.1.255.25565,534
3127.2.0.0/16127.2.0.1 to 127.2.255.254127.2.255.25565,534
4127.3.0.0/16127.3.0.1 to 127.3.255.254127.3.255.25565,534
5127.4.0.0/16127.4.0.1 to 127.4.255.254127.4.255.25565,534
6127.5.0.0/16127.5.0.1 to 127.5.255.254127.5.255.25565,534
7127.6.0.0/16127.6.0.1 to 127.6.255.254127.6.255.25565,534
8127.7.0.0/16127.7.0.1 to 127.7.255.254127.7.255.25565,534
9127.8.0.0/16127.8.0.1 to 127.8.255.254127.8.255.25565,534
10127.9.0.0/16127.9.0.1 to 127.9.255.254127.9.255.25565,534
11127.10.0.0/16127.10.0.1 to 127.10.255.254127.10.255.25565,534
12127.11.0.0/16127.11.0.1 to 127.11.255.254127.11.255.25565,534
13127.12.0.0/16127.12.0.1 to 127.12.255.254127.12.255.25565,534
14127.13.0.0/16127.13.0.1 to 127.13.255.254127.13.255.25565,534
15127.14.0.0/16127.14.0.1 to 127.14.255.254127.14.255.25565,534
16127.15.0.0/16127.15.0.1 to 127.15.255.254127.15.255.25565,534
17127.16.0.0/16127.16.0.1 to 127.16.255.254127.16.255.25565,534
18127.17.0.0/16127.17.0.1 to 127.17.255.254127.17.255.25565,534
19127.18.0.0/16127.18.0.1 to 127.18.255.254127.18.255.25565,534
20127.19.0.0/16127.19.0.1 to 127.19.255.254127.19.255.25565,534
21127.20.0.0/16127.20.0.1 to 127.20.255.254127.20.255.25565,534
22127.21.0.0/16127.21.0.1 to 127.21.255.254127.21.255.25565,534
23127.22.0.0/16127.22.0.1 to 127.22.255.254127.22.255.25565,534
24127.23.0.0/16127.23.0.1 to 127.23.255.254127.23.255.25565,534
25127.24.0.0/16127.24.0.1 to 127.24.255.254127.24.255.25565,534
26127.25.0.0/16127.25.0.1 to 127.25.255.254127.25.255.25565,534
27127.26.0.0/16127.26.0.1 to 127.26.255.254127.26.255.25565,534
28127.27.0.0/16127.27.0.1 to 127.27.255.254127.27.255.25565,534
29127.28.0.0/16127.28.0.1 to 127.28.255.254127.28.255.25565,534
30127.29.0.0/16127.29.0.1 to 127.29.255.254127.29.255.25565,534
31127.30.0.0/16127.30.0.1 to 127.30.255.254127.30.255.25565,534
32127.31.0.0/16127.31.0.1 to 127.31.255.254127.31.255.25565,534
33127.32.0.0/16127.32.0.1 to 127.32.255.254127.32.255.25565,534
34127.33.0.0/16127.33.0.1 to 127.33.255.254127.33.255.25565,534
35127.34.0.0/16127.34.0.1 to 127.34.255.254127.34.255.25565,534
36127.35.0.0/16127.35.0.1 to 127.35.255.254127.35.255.25565,534
37127.36.0.0/16127.36.0.1 to 127.36.255.254127.36.255.25565,534
38127.37.0.0/16127.37.0.1 to 127.37.255.254127.37.255.25565,534
39127.38.0.0/16127.38.0.1 to 127.38.255.254127.38.255.25565,534
40127.39.0.0/16127.39.0.1 to 127.39.255.254127.39.255.25565,534
41127.40.0.0/16127.40.0.1 to 127.40.255.254127.40.255.25565,534
42127.41.0.0/16127.41.0.1 to 127.41.255.254127.41.255.25565,534
43127.42.0.0/16127.42.0.1 to 127.42.255.254127.42.255.25565,534
44127.43.0.0/16127.43.0.1 to 127.43.255.254127.43.255.25565,534
45127.44.0.0/16127.44.0.1 to 127.44.255.254127.44.255.25565,534
46127.45.0.0/16127.45.0.1 to 127.45.255.254127.45.255.25565,534
47127.46.0.0/16127.46.0.1 to 127.46.255.254127.46.255.25565,534
48127.47.0.0/16127.47.0.1 to 127.47.255.254127.47.255.25565,534
49127.48.0.0/16127.48.0.1 to 127.48.255.254127.48.255.25565,534
50127.49.0.0/16127.49.0.1 to 127.49.255.254127.49.255.25565,534
51127.50.0.0/16127.50.0.1 to 127.50.255.254127.50.255.25565,534
52127.51.0.0/16127.51.0.1 to 127.51.255.254127.51.255.25565,534
53127.52.0.0/16127.52.0.1 to 127.52.255.254127.52.255.25565,534
54127.53.0.0/16127.53.0.1 to 127.53.255.254127.53.255.25565,534
55127.54.0.0/16127.54.0.1 to 127.54.255.254127.54.255.25565,534
56127.55.0.0/16127.55.0.1 to 127.55.255.254127.55.255.25565,534
57127.56.0.0/16127.56.0.1 to 127.56.255.254127.56.255.25565,534
58127.57.0.0/16127.57.0.1 to 127.57.255.254127.57.255.25565,534
59127.58.0.0/16127.58.0.1 to 127.58.255.254127.58.255.25565,534
60127.59.0.0/16127.59.0.1 to 127.59.255.254127.59.255.25565,534
61127.60.0.0/16127.60.0.1 to 127.60.255.254127.60.255.25565,534
62127.61.0.0/16127.61.0.1 to 127.61.255.254127.61.255.25565,534
63127.62.0.0/16127.62.0.1 to 127.62.255.254127.62.255.25565,534
64127.63.0.0/16127.63.0.1 to 127.63.255.254127.63.255.25565,534
65127.64.0.0/16127.64.0.1 to 127.64.255.254127.64.255.25565,534
66127.65.0.0/16127.65.0.1 to 127.65.255.254127.65.255.25565,534
67127.66.0.0/16127.66.0.1 to 127.66.255.254127.66.255.25565,534
68127.67.0.0/16127.67.0.1 to 127.67.255.254127.67.255.25565,534
69127.68.0.0/16127.68.0.1 to 127.68.255.254127.68.255.25565,534
70127.69.0.0/16127.69.0.1 to 127.69.255.254127.69.255.25565,534
71127.70.0.0/16127.70.0.1 to 127.70.255.254127.70.255.25565,534
72127.71.0.0/16127.71.0.1 to 127.71.255.254127.71.255.25565,534
73127.72.0.0/16127.72.0.1 to 127.72.255.254127.72.255.25565,534
74127.73.0.0/16127.73.0.1 to 127.73.255.254127.73.255.25565,534
75127.74.0.0/16127.74.0.1 to 127.74.255.254127.74.255.25565,534
76127.75.0.0/16127.75.0.1 to 127.75.255.254127.75.255.25565,534
77127.76.0.0/16127.76.0.1 to 127.76.255.254127.76.255.25565,534
78127.77.0.0/16127.77.0.1 to 127.77.255.254127.77.255.25565,534
79127.78.0.0/16127.78.0.1 to 127.78.255.254127.78.255.25565,534
80127.79.0.0/16127.79.0.1 to 127.79.255.254127.79.255.25565,534
81127.80.0.0/16127.80.0.1 to 127.80.255.254127.80.255.25565,534
82127.81.0.0/16127.81.0.1 to 127.81.255.254127.81.255.25565,534
83127.82.0.0/16127.82.0.1 to 127.82.255.254127.82.255.25565,534
84127.83.0.0/16127.83.0.1 to 127.83.255.254127.83.255.25565,534
85127.84.0.0/16127.84.0.1 to 127.84.255.254127.84.255.25565,534
86127.85.0.0/16127.85.0.1 to 127.85.255.254127.85.255.25565,534
87127.86.0.0/16127.86.0.1 to 127.86.255.254127.86.255.25565,534
88127.87.0.0/16127.87.0.1 to 127.87.255.254127.87.255.25565,534
89127.88.0.0/16127.88.0.1 to 127.88.255.254127.88.255.25565,534
90127.89.0.0/16127.89.0.1 to 127.89.255.254127.89.255.25565,534
91127.90.0.0/16127.90.0.1 to 127.90.255.254127.90.255.25565,534
92127.91.0.0/16127.91.0.1 to 127.91.255.254127.91.255.25565,534
93127.92.0.0/16127.92.0.1 to 127.92.255.254127.92.255.25565,534
94127.93.0.0/16127.93.0.1 to 127.93.255.254127.93.255.25565,534
95127.94.0.0/16127.94.0.1 to 127.94.255.254127.94.255.25565,534
96127.95.0.0/16127.95.0.1 to 127.95.255.254127.95.255.25565,534
97127.96.0.0/16127.96.0.1 to 127.96.255.254127.96.255.25565,534
98127.97.0.0/16127.97.0.1 to 127.97.255.254127.97.255.25565,534
99127.98.0.0/16127.98.0.1 to 127.98.255.254127.98.255.25565,534
100127.99.0.0/16127.99.0.1 to 127.99.255.254127.99.255.25565,534
101127.100.0.0/16127.100.0.1 to 127.100.255.254127.100.255.25565,534
102127.101.0.0/16127.101.0.1 to 127.101.255.254127.101.255.25565,534
103127.102.0.0/16127.102.0.1 to 127.102.255.254127.102.255.25565,534
104127.103.0.0/16127.103.0.1 to 127.103.255.254127.103.255.25565,534
105127.104.0.0/16127.104.0.1 to 127.104.255.254127.104.255.25565,534
106127.105.0.0/16127.105.0.1 to 127.105.255.254127.105.255.25565,534
107127.106.0.0/16127.106.0.1 to 127.106.255.254127.106.255.25565,534
108127.107.0.0/16127.107.0.1 to 127.107.255.254127.107.255.25565,534
109127.108.0.0/16127.108.0.1 to 127.108.255.254127.108.255.25565,534
110127.109.0.0/16127.109.0.1 to 127.109.255.254127.109.255.25565,534
111127.110.0.0/16127.110.0.1 to 127.110.255.254127.110.255.25565,534
112127.111.0.0/16127.111.0.1 to 127.111.255.254127.111.255.25565,534
113127.112.0.0/16127.112.0.1 to 127.112.255.254127.112.255.25565,534
114127.113.0.0/16127.113.0.1 to 127.113.255.254127.113.255.25565,534
115127.114.0.0/16127.114.0.1 to 127.114.255.254127.114.255.25565,534
116127.115.0.0/16127.115.0.1 to 127.115.255.254127.115.255.25565,534
117127.116.0.0/16127.116.0.1 to 127.116.255.254127.116.255.25565,534
118127.117.0.0/16127.117.0.1 to 127.117.255.254127.117.255.25565,534
119127.118.0.0/16127.118.0.1 to 127.118.255.254127.118.255.25565,534
120127.119.0.0/16127.119.0.1 to 127.119.255.254127.119.255.25565,534
121127.120.0.0/16127.120.0.1 to 127.120.255.254127.120.255.25565,534
122127.121.0.0/16127.121.0.1 to 127.121.255.254127.121.255.25565,534
123127.122.0.0/16127.122.0.1 to 127.122.255.254127.122.255.25565,534
124127.123.0.0/16127.123.0.1 to 127.123.255.254127.123.255.25565,534
125127.124.0.0/16127.124.0.1 to 127.124.255.254127.124.255.25565,534
126127.125.0.0/16127.125.0.1 to 127.125.255.254127.125.255.25565,534
127127.126.0.0/16127.126.0.1 to 127.126.255.254127.126.255.25565,534
128127.127.0.0/16127.127.0.1 to 127.127.255.254127.127.255.25565,534
129127.128.0.0/16127.128.0.1 to 127.128.255.254127.128.255.25565,534
130127.129.0.0/16127.129.0.1 to 127.129.255.254127.129.255.25565,534
131127.130.0.0/16127.130.0.1 to 127.130.255.254127.130.255.25565,534
132127.131.0.0/16127.131.0.1 to 127.131.255.254127.131.255.25565,534
133127.132.0.0/16127.132.0.1 to 127.132.255.254127.132.255.25565,534
134127.133.0.0/16127.133.0.1 to 127.133.255.254127.133.255.25565,534
135127.134.0.0/16127.134.0.1 to 127.134.255.254127.134.255.25565,534
136127.135.0.0/16127.135.0.1 to 127.135.255.254127.135.255.25565,534
137127.136.0.0/16127.136.0.1 to 127.136.255.254127.136.255.25565,534
138127.137.0.0/16127.137.0.1 to 127.137.255.254127.137.255.25565,534
139127.138.0.0/16127.138.0.1 to 127.138.255.254127.138.255.25565,534
140127.139.0.0/16127.139.0.1 to 127.139.255.254127.139.255.25565,534
141127.140.0.0/16127.140.0.1 to 127.140.255.254127.140.255.25565,534
142127.141.0.0/16127.141.0.1 to 127.141.255.254127.141.255.25565,534
143127.142.0.0/16127.142.0.1 to 127.142.255.254127.142.255.25565,534
144127.143.0.0/16127.143.0.1 to 127.143.255.254127.143.255.25565,534
145127.144.0.0/16127.144.0.1 to 127.144.255.254127.144.255.25565,534
146127.145.0.0/16127.145.0.1 to 127.145.255.254127.145.255.25565,534
147127.146.0.0/16127.146.0.1 to 127.146.255.254127.146.255.25565,534
148127.147.0.0/16127.147.0.1 to 127.147.255.254127.147.255.25565,534
149127.148.0.0/16127.148.0.1 to 127.148.255.254127.148.255.25565,534
150127.149.0.0/16127.149.0.1 to 127.149.255.254127.149.255.25565,534
151127.150.0.0/16127.150.0.1 to 127.150.255.254127.150.255.25565,534
152127.151.0.0/16127.151.0.1 to 127.151.255.254127.151.255.25565,534
153127.152.0.0/16127.152.0.1 to 127.152.255.254127.152.255.25565,534
154127.153.0.0/16127.153.0.1 to 127.153.255.254127.153.255.25565,534
155127.154.0.0/16127.154.0.1 to 127.154.255.254127.154.255.25565,534
156127.155.0.0/16127.155.0.1 to 127.155.255.254127.155.255.25565,534
157127.156.0.0/16127.156.0.1 to 127.156.255.254127.156.255.25565,534
158127.157.0.0/16127.157.0.1 to 127.157.255.254127.157.255.25565,534
159127.158.0.0/16127.158.0.1 to 127.158.255.254127.158.255.25565,534
160127.159.0.0/16127.159.0.1 to 127.159.255.254127.159.255.25565,534
161127.160.0.0/16127.160.0.1 to 127.160.255.254127.160.255.25565,534
162127.161.0.0/16127.161.0.1 to 127.161.255.254127.161.255.25565,534
163127.162.0.0/16127.162.0.1 to 127.162.255.254127.162.255.25565,534
164127.163.0.0/16127.163.0.1 to 127.163.255.254127.163.255.25565,534
165127.164.0.0/16127.164.0.1 to 127.164.255.254127.164.255.25565,534
166127.165.0.0/16127.165.0.1 to 127.165.255.254127.165.255.25565,534
167127.166.0.0/16127.166.0.1 to 127.166.255.254127.166.255.25565,534
168127.167.0.0/16127.167.0.1 to 127.167.255.254127.167.255.25565,534
169127.168.0.0/16127.168.0.1 to 127.168.255.254127.168.255.25565,534
170127.169.0.0/16127.169.0.1 to 127.169.255.254127.169.255.25565,534
171127.170.0.0/16127.170.0.1 to 127.170.255.254127.170.255.25565,534
172127.171.0.0/16127.171.0.1 to 127.171.255.254127.171.255.25565,534
173127.172.0.0/16127.172.0.1 to 127.172.255.254127.172.255.25565,534
174127.173.0.0/16127.173.0.1 to 127.173.255.254127.173.255.25565,534
175127.174.0.0/16127.174.0.1 to 127.174.255.254127.174.255.25565,534
176127.175.0.0/16127.175.0.1 to 127.175.255.254127.175.255.25565,534
177127.176.0.0/16127.176.0.1 to 127.176.255.254127.176.255.25565,534
178127.177.0.0/16127.177.0.1 to 127.177.255.254127.177.255.25565,534
179127.178.0.0/16127.178.0.1 to 127.178.255.254127.178.255.25565,534
180127.179.0.0/16127.179.0.1 to 127.179.255.254127.179.255.25565,534
181127.180.0.0/16127.180.0.1 to 127.180.255.254127.180.255.25565,534
182127.181.0.0/16127.181.0.1 to 127.181.255.254127.181.255.25565,534
183127.182.0.0/16127.182.0.1 to 127.182.255.254127.182.255.25565,534
184127.183.0.0/16127.183.0.1 to 127.183.255.254127.183.255.25565,534
185127.184.0.0/16127.184.0.1 to 127.184.255.254127.184.255.25565,534
186127.185.0.0/16127.185.0.1 to 127.185.255.254127.185.255.25565,534
187127.186.0.0/16127.186.0.1 to 127.186.255.254127.186.255.25565,534
188127.187.0.0/16127.187.0.1 to 127.187.255.254127.187.255.25565,534
189127.188.0.0/16127.188.0.1 to 127.188.255.254127.188.255.25565,534
190127.189.0.0/16127.189.0.1 to 127.189.255.254127.189.255.25565,534
191127.190.0.0/16127.190.0.1 to 127.190.255.254127.190.255.25565,534
192127.191.0.0/16127.191.0.1 to 127.191.255.254127.191.255.25565,534
193127.192.0.0/16127.192.0.1 to 127.192.255.254127.192.255.25565,534
194127.193.0.0/16127.193.0.1 to 127.193.255.254127.193.255.25565,534
195127.194.0.0/16127.194.0.1 to 127.194.255.254127.194.255.25565,534
196127.195.0.0/16127.195.0.1 to 127.195.255.254127.195.255.25565,534
197127.196.0.0/16127.196.0.1 to 127.196.255.254127.196.255.25565,534
198127.197.0.0/16127.197.0.1 to 127.197.255.254127.197.255.25565,534
199127.198.0.0/16127.198.0.1 to 127.198.255.254127.198.255.25565,534
200127.199.0.0/16127.199.0.1 to 127.199.255.254127.199.255.25565,534
201127.200.0.0/16127.200.0.1 to 127.200.255.254127.200.255.25565,534
202127.201.0.0/16127.201.0.1 to 127.201.255.254127.201.255.25565,534
203127.202.0.0/16127.202.0.1 to 127.202.255.254127.202.255.25565,534
204127.203.0.0/16127.203.0.1 to 127.203.255.254127.203.255.25565,534
205127.204.0.0/16127.204.0.1 to 127.204.255.254127.204.255.25565,534
206127.205.0.0/16127.205.0.1 to 127.205.255.254127.205.255.25565,534
207127.206.0.0/16127.206.0.1 to 127.206.255.254127.206.255.25565,534
208127.207.0.0/16127.207.0.1 to 127.207.255.254127.207.255.25565,534
209127.208.0.0/16127.208.0.1 to 127.208.255.254127.208.255.25565,534
210127.209.0.0/16127.209.0.1 to 127.209.255.254127.209.255.25565,534
211127.210.0.0/16127.210.0.1 to 127.210.255.254127.210.255.25565,534
212127.211.0.0/16127.211.0.1 to 127.211.255.254127.211.255.25565,534
213127.212.0.0/16127.212.0.1 to 127.212.255.254127.212.255.25565,534
214127.213.0.0/16127.213.0.1 to 127.213.255.254127.213.255.25565,534
215127.214.0.0/16127.214.0.1 to 127.214.255.254127.214.255.25565,534
216127.215.0.0/16127.215.0.1 to 127.215.255.254127.215.255.25565,534
217127.216.0.0/16127.216.0.1 to 127.216.255.254127.216.255.25565,534
218127.217.0.0/16127.217.0.1 to 127.217.255.254127.217.255.25565,534
219127.218.0.0/16127.218.0.1 to 127.218.255.254127.218.255.25565,534
220127.219.0.0/16127.219.0.1 to 127.219.255.254127.219.255.25565,534
221127.220.0.0/16127.220.0.1 to 127.220.255.254127.220.255.25565,534
222127.221.0.0/16127.221.0.1 to 127.221.255.254127.221.255.25565,534
223127.222.0.0/16127.222.0.1 to 127.222.255.254127.222.255.25565,534
224127.223.0.0/16127.223.0.1 to 127.223.255.254127.223.255.25565,534
225127.224.0.0/16127.224.0.1 to 127.224.255.254127.224.255.25565,534
226127.225.0.0/16127.225.0.1 to 127.225.255.254127.225.255.25565,534
227127.226.0.0/16127.226.0.1 to 127.226.255.254127.226.255.25565,534
228127.227.0.0/16127.227.0.1 to 127.227.255.254127.227.255.25565,534
229127.228.0.0/16127.228.0.1 to 127.228.255.254127.228.255.25565,534
230127.229.0.0/16127.229.0.1 to 127.229.255.254127.229.255.25565,534
231127.230.0.0/16127.230.0.1 to 127.230.255.254127.230.255.25565,534
232127.231.0.0/16127.231.0.1 to 127.231.255.254127.231.255.25565,534
233127.232.0.0/16127.232.0.1 to 127.232.255.254127.232.255.25565,534
234127.233.0.0/16127.233.0.1 to 127.233.255.254127.233.255.25565,534
235127.234.0.0/16127.234.0.1 to 127.234.255.254127.234.255.25565,534
236127.235.0.0/16127.235.0.1 to 127.235.255.254127.235.255.25565,534
237127.236.0.0/16127.236.0.1 to 127.236.255.254127.236.255.25565,534
238127.237.0.0/16127.237.0.1 to 127.237.255.254127.237.255.25565,534
239127.238.0.0/16127.238.0.1 to 127.238.255.254127.238.255.25565,534
240127.239.0.0/16127.239.0.1 to 127.239.255.254127.239.255.25565,534
241127.240.0.0/16127.240.0.1 to 127.240.255.254127.240.255.25565,534
242127.241.0.0/16127.241.0.1 to 127.241.255.254127.241.255.25565,534
243127.242.0.0/16127.242.0.1 to 127.242.255.254127.242.255.25565,534
244127.243.0.0/16127.243.0.1 to 127.243.255.254127.243.255.25565,534
245127.244.0.0/16127.244.0.1 to 127.244.255.254127.244.255.25565,534
246127.245.0.0/16127.245.0.1 to 127.245.255.254127.245.255.25565,534
247127.246.0.0/16127.246.0.1 to 127.246.255.254127.246.255.25565,534
248127.247.0.0/16127.247.0.1 to 127.247.255.254127.247.255.25565,534
249127.248.0.0/16127.248.0.1 to 127.248.255.254127.248.255.25565,534
250127.249.0.0/16127.249.0.1 to 127.249.255.254127.249.255.25565,534
251127.250.0.0/16127.250.0.1 to 127.250.255.254127.250.255.25565,534
252127.251.0.0/16127.251.0.1 to 127.251.255.254127.251.255.25565,534
253127.252.0.0/16127.252.0.1 to 127.252.255.254127.252.255.25565,534
254127.253.0.0/16127.253.0.1 to 127.253.255.254127.253.255.25565,534
255127.254.0.0/16127.254.0.1 to 127.254.255.254127.254.255.25565,534
256127.255.0.0/16127.255.0.1 to 127.255.255.254127.255.255.25565,534

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.