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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.

Network124.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
124.0.0.0
Broadcast address
125.255.255.255
First usable
124.0.0.1
Last usable
125.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
A (default /8)
As numbers
Hex 7C000000 · Integer 2080374784 to 2113929215
Reverse DNS zones
124.in-addr.arpa
125.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01111100.00000000.00000000.00000000124.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network01111100.00000000.00000000.00000000124.0.0.0
Broadcast01111101.11111111.11111111.11111111125.255.255.255
Split into smaller subnets/16
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

124.0.0.0/7 makes 512 subnets of /16; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1124.0.0.0/16124.0.0.1 to 124.0.255.254124.0.255.25565,534
2124.1.0.0/16124.1.0.1 to 124.1.255.254124.1.255.25565,534
3124.2.0.0/16124.2.0.1 to 124.2.255.254124.2.255.25565,534
4124.3.0.0/16124.3.0.1 to 124.3.255.254124.3.255.25565,534
5124.4.0.0/16124.4.0.1 to 124.4.255.254124.4.255.25565,534
6124.5.0.0/16124.5.0.1 to 124.5.255.254124.5.255.25565,534
7124.6.0.0/16124.6.0.1 to 124.6.255.254124.6.255.25565,534
8124.7.0.0/16124.7.0.1 to 124.7.255.254124.7.255.25565,534
9124.8.0.0/16124.8.0.1 to 124.8.255.254124.8.255.25565,534
10124.9.0.0/16124.9.0.1 to 124.9.255.254124.9.255.25565,534
11124.10.0.0/16124.10.0.1 to 124.10.255.254124.10.255.25565,534
12124.11.0.0/16124.11.0.1 to 124.11.255.254124.11.255.25565,534
13124.12.0.0/16124.12.0.1 to 124.12.255.254124.12.255.25565,534
14124.13.0.0/16124.13.0.1 to 124.13.255.254124.13.255.25565,534
15124.14.0.0/16124.14.0.1 to 124.14.255.254124.14.255.25565,534
16124.15.0.0/16124.15.0.1 to 124.15.255.254124.15.255.25565,534
17124.16.0.0/16124.16.0.1 to 124.16.255.254124.16.255.25565,534
18124.17.0.0/16124.17.0.1 to 124.17.255.254124.17.255.25565,534
19124.18.0.0/16124.18.0.1 to 124.18.255.254124.18.255.25565,534
20124.19.0.0/16124.19.0.1 to 124.19.255.254124.19.255.25565,534
21124.20.0.0/16124.20.0.1 to 124.20.255.254124.20.255.25565,534
22124.21.0.0/16124.21.0.1 to 124.21.255.254124.21.255.25565,534
23124.22.0.0/16124.22.0.1 to 124.22.255.254124.22.255.25565,534
24124.23.0.0/16124.23.0.1 to 124.23.255.254124.23.255.25565,534
25124.24.0.0/16124.24.0.1 to 124.24.255.254124.24.255.25565,534
26124.25.0.0/16124.25.0.1 to 124.25.255.254124.25.255.25565,534
27124.26.0.0/16124.26.0.1 to 124.26.255.254124.26.255.25565,534
28124.27.0.0/16124.27.0.1 to 124.27.255.254124.27.255.25565,534
29124.28.0.0/16124.28.0.1 to 124.28.255.254124.28.255.25565,534
30124.29.0.0/16124.29.0.1 to 124.29.255.254124.29.255.25565,534
31124.30.0.0/16124.30.0.1 to 124.30.255.254124.30.255.25565,534
32124.31.0.0/16124.31.0.1 to 124.31.255.254124.31.255.25565,534
33124.32.0.0/16124.32.0.1 to 124.32.255.254124.32.255.25565,534
34124.33.0.0/16124.33.0.1 to 124.33.255.254124.33.255.25565,534
35124.34.0.0/16124.34.0.1 to 124.34.255.254124.34.255.25565,534
36124.35.0.0/16124.35.0.1 to 124.35.255.254124.35.255.25565,534
37124.36.0.0/16124.36.0.1 to 124.36.255.254124.36.255.25565,534
38124.37.0.0/16124.37.0.1 to 124.37.255.254124.37.255.25565,534
39124.38.0.0/16124.38.0.1 to 124.38.255.254124.38.255.25565,534
40124.39.0.0/16124.39.0.1 to 124.39.255.254124.39.255.25565,534
41124.40.0.0/16124.40.0.1 to 124.40.255.254124.40.255.25565,534
42124.41.0.0/16124.41.0.1 to 124.41.255.254124.41.255.25565,534
43124.42.0.0/16124.42.0.1 to 124.42.255.254124.42.255.25565,534
44124.43.0.0/16124.43.0.1 to 124.43.255.254124.43.255.25565,534
45124.44.0.0/16124.44.0.1 to 124.44.255.254124.44.255.25565,534
46124.45.0.0/16124.45.0.1 to 124.45.255.254124.45.255.25565,534
47124.46.0.0/16124.46.0.1 to 124.46.255.254124.46.255.25565,534
48124.47.0.0/16124.47.0.1 to 124.47.255.254124.47.255.25565,534
49124.48.0.0/16124.48.0.1 to 124.48.255.254124.48.255.25565,534
50124.49.0.0/16124.49.0.1 to 124.49.255.254124.49.255.25565,534
51124.50.0.0/16124.50.0.1 to 124.50.255.254124.50.255.25565,534
52124.51.0.0/16124.51.0.1 to 124.51.255.254124.51.255.25565,534
53124.52.0.0/16124.52.0.1 to 124.52.255.254124.52.255.25565,534
54124.53.0.0/16124.53.0.1 to 124.53.255.254124.53.255.25565,534
55124.54.0.0/16124.54.0.1 to 124.54.255.254124.54.255.25565,534
56124.55.0.0/16124.55.0.1 to 124.55.255.254124.55.255.25565,534
57124.56.0.0/16124.56.0.1 to 124.56.255.254124.56.255.25565,534
58124.57.0.0/16124.57.0.1 to 124.57.255.254124.57.255.25565,534
59124.58.0.0/16124.58.0.1 to 124.58.255.254124.58.255.25565,534
60124.59.0.0/16124.59.0.1 to 124.59.255.254124.59.255.25565,534
61124.60.0.0/16124.60.0.1 to 124.60.255.254124.60.255.25565,534
62124.61.0.0/16124.61.0.1 to 124.61.255.254124.61.255.25565,534
63124.62.0.0/16124.62.0.1 to 124.62.255.254124.62.255.25565,534
64124.63.0.0/16124.63.0.1 to 124.63.255.254124.63.255.25565,534
65124.64.0.0/16124.64.0.1 to 124.64.255.254124.64.255.25565,534
66124.65.0.0/16124.65.0.1 to 124.65.255.254124.65.255.25565,534
67124.66.0.0/16124.66.0.1 to 124.66.255.254124.66.255.25565,534
68124.67.0.0/16124.67.0.1 to 124.67.255.254124.67.255.25565,534
69124.68.0.0/16124.68.0.1 to 124.68.255.254124.68.255.25565,534
70124.69.0.0/16124.69.0.1 to 124.69.255.254124.69.255.25565,534
71124.70.0.0/16124.70.0.1 to 124.70.255.254124.70.255.25565,534
72124.71.0.0/16124.71.0.1 to 124.71.255.254124.71.255.25565,534
73124.72.0.0/16124.72.0.1 to 124.72.255.254124.72.255.25565,534
74124.73.0.0/16124.73.0.1 to 124.73.255.254124.73.255.25565,534
75124.74.0.0/16124.74.0.1 to 124.74.255.254124.74.255.25565,534
76124.75.0.0/16124.75.0.1 to 124.75.255.254124.75.255.25565,534
77124.76.0.0/16124.76.0.1 to 124.76.255.254124.76.255.25565,534
78124.77.0.0/16124.77.0.1 to 124.77.255.254124.77.255.25565,534
79124.78.0.0/16124.78.0.1 to 124.78.255.254124.78.255.25565,534
80124.79.0.0/16124.79.0.1 to 124.79.255.254124.79.255.25565,534
81124.80.0.0/16124.80.0.1 to 124.80.255.254124.80.255.25565,534
82124.81.0.0/16124.81.0.1 to 124.81.255.254124.81.255.25565,534
83124.82.0.0/16124.82.0.1 to 124.82.255.254124.82.255.25565,534
84124.83.0.0/16124.83.0.1 to 124.83.255.254124.83.255.25565,534
85124.84.0.0/16124.84.0.1 to 124.84.255.254124.84.255.25565,534
86124.85.0.0/16124.85.0.1 to 124.85.255.254124.85.255.25565,534
87124.86.0.0/16124.86.0.1 to 124.86.255.254124.86.255.25565,534
88124.87.0.0/16124.87.0.1 to 124.87.255.254124.87.255.25565,534
89124.88.0.0/16124.88.0.1 to 124.88.255.254124.88.255.25565,534
90124.89.0.0/16124.89.0.1 to 124.89.255.254124.89.255.25565,534
91124.90.0.0/16124.90.0.1 to 124.90.255.254124.90.255.25565,534
92124.91.0.0/16124.91.0.1 to 124.91.255.254124.91.255.25565,534
93124.92.0.0/16124.92.0.1 to 124.92.255.254124.92.255.25565,534
94124.93.0.0/16124.93.0.1 to 124.93.255.254124.93.255.25565,534
95124.94.0.0/16124.94.0.1 to 124.94.255.254124.94.255.25565,534
96124.95.0.0/16124.95.0.1 to 124.95.255.254124.95.255.25565,534
97124.96.0.0/16124.96.0.1 to 124.96.255.254124.96.255.25565,534
98124.97.0.0/16124.97.0.1 to 124.97.255.254124.97.255.25565,534
99124.98.0.0/16124.98.0.1 to 124.98.255.254124.98.255.25565,534
100124.99.0.0/16124.99.0.1 to 124.99.255.254124.99.255.25565,534
101124.100.0.0/16124.100.0.1 to 124.100.255.254124.100.255.25565,534
102124.101.0.0/16124.101.0.1 to 124.101.255.254124.101.255.25565,534
103124.102.0.0/16124.102.0.1 to 124.102.255.254124.102.255.25565,534
104124.103.0.0/16124.103.0.1 to 124.103.255.254124.103.255.25565,534
105124.104.0.0/16124.104.0.1 to 124.104.255.254124.104.255.25565,534
106124.105.0.0/16124.105.0.1 to 124.105.255.254124.105.255.25565,534
107124.106.0.0/16124.106.0.1 to 124.106.255.254124.106.255.25565,534
108124.107.0.0/16124.107.0.1 to 124.107.255.254124.107.255.25565,534
109124.108.0.0/16124.108.0.1 to 124.108.255.254124.108.255.25565,534
110124.109.0.0/16124.109.0.1 to 124.109.255.254124.109.255.25565,534
111124.110.0.0/16124.110.0.1 to 124.110.255.254124.110.255.25565,534
112124.111.0.0/16124.111.0.1 to 124.111.255.254124.111.255.25565,534
113124.112.0.0/16124.112.0.1 to 124.112.255.254124.112.255.25565,534
114124.113.0.0/16124.113.0.1 to 124.113.255.254124.113.255.25565,534
115124.114.0.0/16124.114.0.1 to 124.114.255.254124.114.255.25565,534
116124.115.0.0/16124.115.0.1 to 124.115.255.254124.115.255.25565,534
117124.116.0.0/16124.116.0.1 to 124.116.255.254124.116.255.25565,534
118124.117.0.0/16124.117.0.1 to 124.117.255.254124.117.255.25565,534
119124.118.0.0/16124.118.0.1 to 124.118.255.254124.118.255.25565,534
120124.119.0.0/16124.119.0.1 to 124.119.255.254124.119.255.25565,534
121124.120.0.0/16124.120.0.1 to 124.120.255.254124.120.255.25565,534
122124.121.0.0/16124.121.0.1 to 124.121.255.254124.121.255.25565,534
123124.122.0.0/16124.122.0.1 to 124.122.255.254124.122.255.25565,534
124124.123.0.0/16124.123.0.1 to 124.123.255.254124.123.255.25565,534
125124.124.0.0/16124.124.0.1 to 124.124.255.254124.124.255.25565,534
126124.125.0.0/16124.125.0.1 to 124.125.255.254124.125.255.25565,534
127124.126.0.0/16124.126.0.1 to 124.126.255.254124.126.255.25565,534
128124.127.0.0/16124.127.0.1 to 124.127.255.254124.127.255.25565,534
129124.128.0.0/16124.128.0.1 to 124.128.255.254124.128.255.25565,534
130124.129.0.0/16124.129.0.1 to 124.129.255.254124.129.255.25565,534
131124.130.0.0/16124.130.0.1 to 124.130.255.254124.130.255.25565,534
132124.131.0.0/16124.131.0.1 to 124.131.255.254124.131.255.25565,534
133124.132.0.0/16124.132.0.1 to 124.132.255.254124.132.255.25565,534
134124.133.0.0/16124.133.0.1 to 124.133.255.254124.133.255.25565,534
135124.134.0.0/16124.134.0.1 to 124.134.255.254124.134.255.25565,534
136124.135.0.0/16124.135.0.1 to 124.135.255.254124.135.255.25565,534
137124.136.0.0/16124.136.0.1 to 124.136.255.254124.136.255.25565,534
138124.137.0.0/16124.137.0.1 to 124.137.255.254124.137.255.25565,534
139124.138.0.0/16124.138.0.1 to 124.138.255.254124.138.255.25565,534
140124.139.0.0/16124.139.0.1 to 124.139.255.254124.139.255.25565,534
141124.140.0.0/16124.140.0.1 to 124.140.255.254124.140.255.25565,534
142124.141.0.0/16124.141.0.1 to 124.141.255.254124.141.255.25565,534
143124.142.0.0/16124.142.0.1 to 124.142.255.254124.142.255.25565,534
144124.143.0.0/16124.143.0.1 to 124.143.255.254124.143.255.25565,534
145124.144.0.0/16124.144.0.1 to 124.144.255.254124.144.255.25565,534
146124.145.0.0/16124.145.0.1 to 124.145.255.254124.145.255.25565,534
147124.146.0.0/16124.146.0.1 to 124.146.255.254124.146.255.25565,534
148124.147.0.0/16124.147.0.1 to 124.147.255.254124.147.255.25565,534
149124.148.0.0/16124.148.0.1 to 124.148.255.254124.148.255.25565,534
150124.149.0.0/16124.149.0.1 to 124.149.255.254124.149.255.25565,534
151124.150.0.0/16124.150.0.1 to 124.150.255.254124.150.255.25565,534
152124.151.0.0/16124.151.0.1 to 124.151.255.254124.151.255.25565,534
153124.152.0.0/16124.152.0.1 to 124.152.255.254124.152.255.25565,534
154124.153.0.0/16124.153.0.1 to 124.153.255.254124.153.255.25565,534
155124.154.0.0/16124.154.0.1 to 124.154.255.254124.154.255.25565,534
156124.155.0.0/16124.155.0.1 to 124.155.255.254124.155.255.25565,534
157124.156.0.0/16124.156.0.1 to 124.156.255.254124.156.255.25565,534
158124.157.0.0/16124.157.0.1 to 124.157.255.254124.157.255.25565,534
159124.158.0.0/16124.158.0.1 to 124.158.255.254124.158.255.25565,534
160124.159.0.0/16124.159.0.1 to 124.159.255.254124.159.255.25565,534
161124.160.0.0/16124.160.0.1 to 124.160.255.254124.160.255.25565,534
162124.161.0.0/16124.161.0.1 to 124.161.255.254124.161.255.25565,534
163124.162.0.0/16124.162.0.1 to 124.162.255.254124.162.255.25565,534
164124.163.0.0/16124.163.0.1 to 124.163.255.254124.163.255.25565,534
165124.164.0.0/16124.164.0.1 to 124.164.255.254124.164.255.25565,534
166124.165.0.0/16124.165.0.1 to 124.165.255.254124.165.255.25565,534
167124.166.0.0/16124.166.0.1 to 124.166.255.254124.166.255.25565,534
168124.167.0.0/16124.167.0.1 to 124.167.255.254124.167.255.25565,534
169124.168.0.0/16124.168.0.1 to 124.168.255.254124.168.255.25565,534
170124.169.0.0/16124.169.0.1 to 124.169.255.254124.169.255.25565,534
171124.170.0.0/16124.170.0.1 to 124.170.255.254124.170.255.25565,534
172124.171.0.0/16124.171.0.1 to 124.171.255.254124.171.255.25565,534
173124.172.0.0/16124.172.0.1 to 124.172.255.254124.172.255.25565,534
174124.173.0.0/16124.173.0.1 to 124.173.255.254124.173.255.25565,534
175124.174.0.0/16124.174.0.1 to 124.174.255.254124.174.255.25565,534
176124.175.0.0/16124.175.0.1 to 124.175.255.254124.175.255.25565,534
177124.176.0.0/16124.176.0.1 to 124.176.255.254124.176.255.25565,534
178124.177.0.0/16124.177.0.1 to 124.177.255.254124.177.255.25565,534
179124.178.0.0/16124.178.0.1 to 124.178.255.254124.178.255.25565,534
180124.179.0.0/16124.179.0.1 to 124.179.255.254124.179.255.25565,534
181124.180.0.0/16124.180.0.1 to 124.180.255.254124.180.255.25565,534
182124.181.0.0/16124.181.0.1 to 124.181.255.254124.181.255.25565,534
183124.182.0.0/16124.182.0.1 to 124.182.255.254124.182.255.25565,534
184124.183.0.0/16124.183.0.1 to 124.183.255.254124.183.255.25565,534
185124.184.0.0/16124.184.0.1 to 124.184.255.254124.184.255.25565,534
186124.185.0.0/16124.185.0.1 to 124.185.255.254124.185.255.25565,534
187124.186.0.0/16124.186.0.1 to 124.186.255.254124.186.255.25565,534
188124.187.0.0/16124.187.0.1 to 124.187.255.254124.187.255.25565,534
189124.188.0.0/16124.188.0.1 to 124.188.255.254124.188.255.25565,534
190124.189.0.0/16124.189.0.1 to 124.189.255.254124.189.255.25565,534
191124.190.0.0/16124.190.0.1 to 124.190.255.254124.190.255.25565,534
192124.191.0.0/16124.191.0.1 to 124.191.255.254124.191.255.25565,534
193124.192.0.0/16124.192.0.1 to 124.192.255.254124.192.255.25565,534
194124.193.0.0/16124.193.0.1 to 124.193.255.254124.193.255.25565,534
195124.194.0.0/16124.194.0.1 to 124.194.255.254124.194.255.25565,534
196124.195.0.0/16124.195.0.1 to 124.195.255.254124.195.255.25565,534
197124.196.0.0/16124.196.0.1 to 124.196.255.254124.196.255.25565,534
198124.197.0.0/16124.197.0.1 to 124.197.255.254124.197.255.25565,534
199124.198.0.0/16124.198.0.1 to 124.198.255.254124.198.255.25565,534
200124.199.0.0/16124.199.0.1 to 124.199.255.254124.199.255.25565,534
201124.200.0.0/16124.200.0.1 to 124.200.255.254124.200.255.25565,534
202124.201.0.0/16124.201.0.1 to 124.201.255.254124.201.255.25565,534
203124.202.0.0/16124.202.0.1 to 124.202.255.254124.202.255.25565,534
204124.203.0.0/16124.203.0.1 to 124.203.255.254124.203.255.25565,534
205124.204.0.0/16124.204.0.1 to 124.204.255.254124.204.255.25565,534
206124.205.0.0/16124.205.0.1 to 124.205.255.254124.205.255.25565,534
207124.206.0.0/16124.206.0.1 to 124.206.255.254124.206.255.25565,534
208124.207.0.0/16124.207.0.1 to 124.207.255.254124.207.255.25565,534
209124.208.0.0/16124.208.0.1 to 124.208.255.254124.208.255.25565,534
210124.209.0.0/16124.209.0.1 to 124.209.255.254124.209.255.25565,534
211124.210.0.0/16124.210.0.1 to 124.210.255.254124.210.255.25565,534
212124.211.0.0/16124.211.0.1 to 124.211.255.254124.211.255.25565,534
213124.212.0.0/16124.212.0.1 to 124.212.255.254124.212.255.25565,534
214124.213.0.0/16124.213.0.1 to 124.213.255.254124.213.255.25565,534
215124.214.0.0/16124.214.0.1 to 124.214.255.254124.214.255.25565,534
216124.215.0.0/16124.215.0.1 to 124.215.255.254124.215.255.25565,534
217124.216.0.0/16124.216.0.1 to 124.216.255.254124.216.255.25565,534
218124.217.0.0/16124.217.0.1 to 124.217.255.254124.217.255.25565,534
219124.218.0.0/16124.218.0.1 to 124.218.255.254124.218.255.25565,534
220124.219.0.0/16124.219.0.1 to 124.219.255.254124.219.255.25565,534
221124.220.0.0/16124.220.0.1 to 124.220.255.254124.220.255.25565,534
222124.221.0.0/16124.221.0.1 to 124.221.255.254124.221.255.25565,534
223124.222.0.0/16124.222.0.1 to 124.222.255.254124.222.255.25565,534
224124.223.0.0/16124.223.0.1 to 124.223.255.254124.223.255.25565,534
225124.224.0.0/16124.224.0.1 to 124.224.255.254124.224.255.25565,534
226124.225.0.0/16124.225.0.1 to 124.225.255.254124.225.255.25565,534
227124.226.0.0/16124.226.0.1 to 124.226.255.254124.226.255.25565,534
228124.227.0.0/16124.227.0.1 to 124.227.255.254124.227.255.25565,534
229124.228.0.0/16124.228.0.1 to 124.228.255.254124.228.255.25565,534
230124.229.0.0/16124.229.0.1 to 124.229.255.254124.229.255.25565,534
231124.230.0.0/16124.230.0.1 to 124.230.255.254124.230.255.25565,534
232124.231.0.0/16124.231.0.1 to 124.231.255.254124.231.255.25565,534
233124.232.0.0/16124.232.0.1 to 124.232.255.254124.232.255.25565,534
234124.233.0.0/16124.233.0.1 to 124.233.255.254124.233.255.25565,534
235124.234.0.0/16124.234.0.1 to 124.234.255.254124.234.255.25565,534
236124.235.0.0/16124.235.0.1 to 124.235.255.254124.235.255.25565,534
237124.236.0.0/16124.236.0.1 to 124.236.255.254124.236.255.25565,534
238124.237.0.0/16124.237.0.1 to 124.237.255.254124.237.255.25565,534
239124.238.0.0/16124.238.0.1 to 124.238.255.254124.238.255.25565,534
240124.239.0.0/16124.239.0.1 to 124.239.255.254124.239.255.25565,534
241124.240.0.0/16124.240.0.1 to 124.240.255.254124.240.255.25565,534
242124.241.0.0/16124.241.0.1 to 124.241.255.254124.241.255.25565,534
243124.242.0.0/16124.242.0.1 to 124.242.255.254124.242.255.25565,534
244124.243.0.0/16124.243.0.1 to 124.243.255.254124.243.255.25565,534
245124.244.0.0/16124.244.0.1 to 124.244.255.254124.244.255.25565,534
246124.245.0.0/16124.245.0.1 to 124.245.255.254124.245.255.25565,534
247124.246.0.0/16124.246.0.1 to 124.246.255.254124.246.255.25565,534
248124.247.0.0/16124.247.0.1 to 124.247.255.254124.247.255.25565,534
249124.248.0.0/16124.248.0.1 to 124.248.255.254124.248.255.25565,534
250124.249.0.0/16124.249.0.1 to 124.249.255.254124.249.255.25565,534
251124.250.0.0/16124.250.0.1 to 124.250.255.254124.250.255.25565,534
252124.251.0.0/16124.251.0.1 to 124.251.255.254124.251.255.25565,534
253124.252.0.0/16124.252.0.1 to 124.252.255.254124.252.255.25565,534
254124.253.0.0/16124.253.0.1 to 124.253.255.254124.253.255.25565,534
255124.254.0.0/16124.254.0.1 to 124.254.255.254124.254.255.25565,534
256124.255.0.0/16124.255.0.1 to 124.255.255.254124.255.255.25565,534

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.