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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.

Network124.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
124.0.0.0
Broadcast address
127.255.255.255
First usable
124.0.0.1
Last usable
127.255.255.254
Usable hosts
67,108,862 (67,108,864 less the network and broadcast addresses)
Subnet mask
252.0.0.0
Wildcard mask
3.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/6
Type
Public public
Old class
A (default /8)
As numbers
Hex 7C000000 · Integer 2080374784 to 2147483647
Reverse DNS zones
124.in-addr.arpa
125.in-addr.arpa
126.in-addr.arpa
127.in-addr.arpa
/6 is not on a 8-bit boundary, so it takes 4 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01111100.00000000.00000000.00000000124.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network01111100.00000000.00000000.00000000124.0.0.0
Broadcast01111111.11111111.11111111.11111111127.255.255.255
Split into smaller subnets/15
/7 (2)/8 (4)/9 (8)/10 (16)/11 (32)/12 (64)/13 (128)/14 (256)/15 (512)/16 (1,024)/17 (2,048)/18 (4,096)

124.0.0.0/6 makes 512 subnets of /15; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1124.0.0.0/15124.0.0.1 to 124.1.255.254124.1.255.255131,070
2124.2.0.0/15124.2.0.1 to 124.3.255.254124.3.255.255131,070
3124.4.0.0/15124.4.0.1 to 124.5.255.254124.5.255.255131,070
4124.6.0.0/15124.6.0.1 to 124.7.255.254124.7.255.255131,070
5124.8.0.0/15124.8.0.1 to 124.9.255.254124.9.255.255131,070
6124.10.0.0/15124.10.0.1 to 124.11.255.254124.11.255.255131,070
7124.12.0.0/15124.12.0.1 to 124.13.255.254124.13.255.255131,070
8124.14.0.0/15124.14.0.1 to 124.15.255.254124.15.255.255131,070
9124.16.0.0/15124.16.0.1 to 124.17.255.254124.17.255.255131,070
10124.18.0.0/15124.18.0.1 to 124.19.255.254124.19.255.255131,070
11124.20.0.0/15124.20.0.1 to 124.21.255.254124.21.255.255131,070
12124.22.0.0/15124.22.0.1 to 124.23.255.254124.23.255.255131,070
13124.24.0.0/15124.24.0.1 to 124.25.255.254124.25.255.255131,070
14124.26.0.0/15124.26.0.1 to 124.27.255.254124.27.255.255131,070
15124.28.0.0/15124.28.0.1 to 124.29.255.254124.29.255.255131,070
16124.30.0.0/15124.30.0.1 to 124.31.255.254124.31.255.255131,070
17124.32.0.0/15124.32.0.1 to 124.33.255.254124.33.255.255131,070
18124.34.0.0/15124.34.0.1 to 124.35.255.254124.35.255.255131,070
19124.36.0.0/15124.36.0.1 to 124.37.255.254124.37.255.255131,070
20124.38.0.0/15124.38.0.1 to 124.39.255.254124.39.255.255131,070
21124.40.0.0/15124.40.0.1 to 124.41.255.254124.41.255.255131,070
22124.42.0.0/15124.42.0.1 to 124.43.255.254124.43.255.255131,070
23124.44.0.0/15124.44.0.1 to 124.45.255.254124.45.255.255131,070
24124.46.0.0/15124.46.0.1 to 124.47.255.254124.47.255.255131,070
25124.48.0.0/15124.48.0.1 to 124.49.255.254124.49.255.255131,070
26124.50.0.0/15124.50.0.1 to 124.51.255.254124.51.255.255131,070
27124.52.0.0/15124.52.0.1 to 124.53.255.254124.53.255.255131,070
28124.54.0.0/15124.54.0.1 to 124.55.255.254124.55.255.255131,070
29124.56.0.0/15124.56.0.1 to 124.57.255.254124.57.255.255131,070
30124.58.0.0/15124.58.0.1 to 124.59.255.254124.59.255.255131,070
31124.60.0.0/15124.60.0.1 to 124.61.255.254124.61.255.255131,070
32124.62.0.0/15124.62.0.1 to 124.63.255.254124.63.255.255131,070
33124.64.0.0/15124.64.0.1 to 124.65.255.254124.65.255.255131,070
34124.66.0.0/15124.66.0.1 to 124.67.255.254124.67.255.255131,070
35124.68.0.0/15124.68.0.1 to 124.69.255.254124.69.255.255131,070
36124.70.0.0/15124.70.0.1 to 124.71.255.254124.71.255.255131,070
37124.72.0.0/15124.72.0.1 to 124.73.255.254124.73.255.255131,070
38124.74.0.0/15124.74.0.1 to 124.75.255.254124.75.255.255131,070
39124.76.0.0/15124.76.0.1 to 124.77.255.254124.77.255.255131,070
40124.78.0.0/15124.78.0.1 to 124.79.255.254124.79.255.255131,070
41124.80.0.0/15124.80.0.1 to 124.81.255.254124.81.255.255131,070
42124.82.0.0/15124.82.0.1 to 124.83.255.254124.83.255.255131,070
43124.84.0.0/15124.84.0.1 to 124.85.255.254124.85.255.255131,070
44124.86.0.0/15124.86.0.1 to 124.87.255.254124.87.255.255131,070
45124.88.0.0/15124.88.0.1 to 124.89.255.254124.89.255.255131,070
46124.90.0.0/15124.90.0.1 to 124.91.255.254124.91.255.255131,070
47124.92.0.0/15124.92.0.1 to 124.93.255.254124.93.255.255131,070
48124.94.0.0/15124.94.0.1 to 124.95.255.254124.95.255.255131,070
49124.96.0.0/15124.96.0.1 to 124.97.255.254124.97.255.255131,070
50124.98.0.0/15124.98.0.1 to 124.99.255.254124.99.255.255131,070
51124.100.0.0/15124.100.0.1 to 124.101.255.254124.101.255.255131,070
52124.102.0.0/15124.102.0.1 to 124.103.255.254124.103.255.255131,070
53124.104.0.0/15124.104.0.1 to 124.105.255.254124.105.255.255131,070
54124.106.0.0/15124.106.0.1 to 124.107.255.254124.107.255.255131,070
55124.108.0.0/15124.108.0.1 to 124.109.255.254124.109.255.255131,070
56124.110.0.0/15124.110.0.1 to 124.111.255.254124.111.255.255131,070
57124.112.0.0/15124.112.0.1 to 124.113.255.254124.113.255.255131,070
58124.114.0.0/15124.114.0.1 to 124.115.255.254124.115.255.255131,070
59124.116.0.0/15124.116.0.1 to 124.117.255.254124.117.255.255131,070
60124.118.0.0/15124.118.0.1 to 124.119.255.254124.119.255.255131,070
61124.120.0.0/15124.120.0.1 to 124.121.255.254124.121.255.255131,070
62124.122.0.0/15124.122.0.1 to 124.123.255.254124.123.255.255131,070
63124.124.0.0/15124.124.0.1 to 124.125.255.254124.125.255.255131,070
64124.126.0.0/15124.126.0.1 to 124.127.255.254124.127.255.255131,070
65124.128.0.0/15124.128.0.1 to 124.129.255.254124.129.255.255131,070
66124.130.0.0/15124.130.0.1 to 124.131.255.254124.131.255.255131,070
67124.132.0.0/15124.132.0.1 to 124.133.255.254124.133.255.255131,070
68124.134.0.0/15124.134.0.1 to 124.135.255.254124.135.255.255131,070
69124.136.0.0/15124.136.0.1 to 124.137.255.254124.137.255.255131,070
70124.138.0.0/15124.138.0.1 to 124.139.255.254124.139.255.255131,070
71124.140.0.0/15124.140.0.1 to 124.141.255.254124.141.255.255131,070
72124.142.0.0/15124.142.0.1 to 124.143.255.254124.143.255.255131,070
73124.144.0.0/15124.144.0.1 to 124.145.255.254124.145.255.255131,070
74124.146.0.0/15124.146.0.1 to 124.147.255.254124.147.255.255131,070
75124.148.0.0/15124.148.0.1 to 124.149.255.254124.149.255.255131,070
76124.150.0.0/15124.150.0.1 to 124.151.255.254124.151.255.255131,070
77124.152.0.0/15124.152.0.1 to 124.153.255.254124.153.255.255131,070
78124.154.0.0/15124.154.0.1 to 124.155.255.254124.155.255.255131,070
79124.156.0.0/15124.156.0.1 to 124.157.255.254124.157.255.255131,070
80124.158.0.0/15124.158.0.1 to 124.159.255.254124.159.255.255131,070
81124.160.0.0/15124.160.0.1 to 124.161.255.254124.161.255.255131,070
82124.162.0.0/15124.162.0.1 to 124.163.255.254124.163.255.255131,070
83124.164.0.0/15124.164.0.1 to 124.165.255.254124.165.255.255131,070
84124.166.0.0/15124.166.0.1 to 124.167.255.254124.167.255.255131,070
85124.168.0.0/15124.168.0.1 to 124.169.255.254124.169.255.255131,070
86124.170.0.0/15124.170.0.1 to 124.171.255.254124.171.255.255131,070
87124.172.0.0/15124.172.0.1 to 124.173.255.254124.173.255.255131,070
88124.174.0.0/15124.174.0.1 to 124.175.255.254124.175.255.255131,070
89124.176.0.0/15124.176.0.1 to 124.177.255.254124.177.255.255131,070
90124.178.0.0/15124.178.0.1 to 124.179.255.254124.179.255.255131,070
91124.180.0.0/15124.180.0.1 to 124.181.255.254124.181.255.255131,070
92124.182.0.0/15124.182.0.1 to 124.183.255.254124.183.255.255131,070
93124.184.0.0/15124.184.0.1 to 124.185.255.254124.185.255.255131,070
94124.186.0.0/15124.186.0.1 to 124.187.255.254124.187.255.255131,070
95124.188.0.0/15124.188.0.1 to 124.189.255.254124.189.255.255131,070
96124.190.0.0/15124.190.0.1 to 124.191.255.254124.191.255.255131,070
97124.192.0.0/15124.192.0.1 to 124.193.255.254124.193.255.255131,070
98124.194.0.0/15124.194.0.1 to 124.195.255.254124.195.255.255131,070
99124.196.0.0/15124.196.0.1 to 124.197.255.254124.197.255.255131,070
100124.198.0.0/15124.198.0.1 to 124.199.255.254124.199.255.255131,070
101124.200.0.0/15124.200.0.1 to 124.201.255.254124.201.255.255131,070
102124.202.0.0/15124.202.0.1 to 124.203.255.254124.203.255.255131,070
103124.204.0.0/15124.204.0.1 to 124.205.255.254124.205.255.255131,070
104124.206.0.0/15124.206.0.1 to 124.207.255.254124.207.255.255131,070
105124.208.0.0/15124.208.0.1 to 124.209.255.254124.209.255.255131,070
106124.210.0.0/15124.210.0.1 to 124.211.255.254124.211.255.255131,070
107124.212.0.0/15124.212.0.1 to 124.213.255.254124.213.255.255131,070
108124.214.0.0/15124.214.0.1 to 124.215.255.254124.215.255.255131,070
109124.216.0.0/15124.216.0.1 to 124.217.255.254124.217.255.255131,070
110124.218.0.0/15124.218.0.1 to 124.219.255.254124.219.255.255131,070
111124.220.0.0/15124.220.0.1 to 124.221.255.254124.221.255.255131,070
112124.222.0.0/15124.222.0.1 to 124.223.255.254124.223.255.255131,070
113124.224.0.0/15124.224.0.1 to 124.225.255.254124.225.255.255131,070
114124.226.0.0/15124.226.0.1 to 124.227.255.254124.227.255.255131,070
115124.228.0.0/15124.228.0.1 to 124.229.255.254124.229.255.255131,070
116124.230.0.0/15124.230.0.1 to 124.231.255.254124.231.255.255131,070
117124.232.0.0/15124.232.0.1 to 124.233.255.254124.233.255.255131,070
118124.234.0.0/15124.234.0.1 to 124.235.255.254124.235.255.255131,070
119124.236.0.0/15124.236.0.1 to 124.237.255.254124.237.255.255131,070
120124.238.0.0/15124.238.0.1 to 124.239.255.254124.239.255.255131,070
121124.240.0.0/15124.240.0.1 to 124.241.255.254124.241.255.255131,070
122124.242.0.0/15124.242.0.1 to 124.243.255.254124.243.255.255131,070
123124.244.0.0/15124.244.0.1 to 124.245.255.254124.245.255.255131,070
124124.246.0.0/15124.246.0.1 to 124.247.255.254124.247.255.255131,070
125124.248.0.0/15124.248.0.1 to 124.249.255.254124.249.255.255131,070
126124.250.0.0/15124.250.0.1 to 124.251.255.254124.251.255.255131,070
127124.252.0.0/15124.252.0.1 to 124.253.255.254124.253.255.255131,070
128124.254.0.0/15124.254.0.1 to 124.255.255.254124.255.255.255131,070
129125.0.0.0/15125.0.0.1 to 125.1.255.254125.1.255.255131,070
130125.2.0.0/15125.2.0.1 to 125.3.255.254125.3.255.255131,070
131125.4.0.0/15125.4.0.1 to 125.5.255.254125.5.255.255131,070
132125.6.0.0/15125.6.0.1 to 125.7.255.254125.7.255.255131,070
133125.8.0.0/15125.8.0.1 to 125.9.255.254125.9.255.255131,070
134125.10.0.0/15125.10.0.1 to 125.11.255.254125.11.255.255131,070
135125.12.0.0/15125.12.0.1 to 125.13.255.254125.13.255.255131,070
136125.14.0.0/15125.14.0.1 to 125.15.255.254125.15.255.255131,070
137125.16.0.0/15125.16.0.1 to 125.17.255.254125.17.255.255131,070
138125.18.0.0/15125.18.0.1 to 125.19.255.254125.19.255.255131,070
139125.20.0.0/15125.20.0.1 to 125.21.255.254125.21.255.255131,070
140125.22.0.0/15125.22.0.1 to 125.23.255.254125.23.255.255131,070
141125.24.0.0/15125.24.0.1 to 125.25.255.254125.25.255.255131,070
142125.26.0.0/15125.26.0.1 to 125.27.255.254125.27.255.255131,070
143125.28.0.0/15125.28.0.1 to 125.29.255.254125.29.255.255131,070
144125.30.0.0/15125.30.0.1 to 125.31.255.254125.31.255.255131,070
145125.32.0.0/15125.32.0.1 to 125.33.255.254125.33.255.255131,070
146125.34.0.0/15125.34.0.1 to 125.35.255.254125.35.255.255131,070
147125.36.0.0/15125.36.0.1 to 125.37.255.254125.37.255.255131,070
148125.38.0.0/15125.38.0.1 to 125.39.255.254125.39.255.255131,070
149125.40.0.0/15125.40.0.1 to 125.41.255.254125.41.255.255131,070
150125.42.0.0/15125.42.0.1 to 125.43.255.254125.43.255.255131,070
151125.44.0.0/15125.44.0.1 to 125.45.255.254125.45.255.255131,070
152125.46.0.0/15125.46.0.1 to 125.47.255.254125.47.255.255131,070
153125.48.0.0/15125.48.0.1 to 125.49.255.254125.49.255.255131,070
154125.50.0.0/15125.50.0.1 to 125.51.255.254125.51.255.255131,070
155125.52.0.0/15125.52.0.1 to 125.53.255.254125.53.255.255131,070
156125.54.0.0/15125.54.0.1 to 125.55.255.254125.55.255.255131,070
157125.56.0.0/15125.56.0.1 to 125.57.255.254125.57.255.255131,070
158125.58.0.0/15125.58.0.1 to 125.59.255.254125.59.255.255131,070
159125.60.0.0/15125.60.0.1 to 125.61.255.254125.61.255.255131,070
160125.62.0.0/15125.62.0.1 to 125.63.255.254125.63.255.255131,070
161125.64.0.0/15125.64.0.1 to 125.65.255.254125.65.255.255131,070
162125.66.0.0/15125.66.0.1 to 125.67.255.254125.67.255.255131,070
163125.68.0.0/15125.68.0.1 to 125.69.255.254125.69.255.255131,070
164125.70.0.0/15125.70.0.1 to 125.71.255.254125.71.255.255131,070
165125.72.0.0/15125.72.0.1 to 125.73.255.254125.73.255.255131,070
166125.74.0.0/15125.74.0.1 to 125.75.255.254125.75.255.255131,070
167125.76.0.0/15125.76.0.1 to 125.77.255.254125.77.255.255131,070
168125.78.0.0/15125.78.0.1 to 125.79.255.254125.79.255.255131,070
169125.80.0.0/15125.80.0.1 to 125.81.255.254125.81.255.255131,070
170125.82.0.0/15125.82.0.1 to 125.83.255.254125.83.255.255131,070
171125.84.0.0/15125.84.0.1 to 125.85.255.254125.85.255.255131,070
172125.86.0.0/15125.86.0.1 to 125.87.255.254125.87.255.255131,070
173125.88.0.0/15125.88.0.1 to 125.89.255.254125.89.255.255131,070
174125.90.0.0/15125.90.0.1 to 125.91.255.254125.91.255.255131,070
175125.92.0.0/15125.92.0.1 to 125.93.255.254125.93.255.255131,070
176125.94.0.0/15125.94.0.1 to 125.95.255.254125.95.255.255131,070
177125.96.0.0/15125.96.0.1 to 125.97.255.254125.97.255.255131,070
178125.98.0.0/15125.98.0.1 to 125.99.255.254125.99.255.255131,070
179125.100.0.0/15125.100.0.1 to 125.101.255.254125.101.255.255131,070
180125.102.0.0/15125.102.0.1 to 125.103.255.254125.103.255.255131,070
181125.104.0.0/15125.104.0.1 to 125.105.255.254125.105.255.255131,070
182125.106.0.0/15125.106.0.1 to 125.107.255.254125.107.255.255131,070
183125.108.0.0/15125.108.0.1 to 125.109.255.254125.109.255.255131,070
184125.110.0.0/15125.110.0.1 to 125.111.255.254125.111.255.255131,070
185125.112.0.0/15125.112.0.1 to 125.113.255.254125.113.255.255131,070
186125.114.0.0/15125.114.0.1 to 125.115.255.254125.115.255.255131,070
187125.116.0.0/15125.116.0.1 to 125.117.255.254125.117.255.255131,070
188125.118.0.0/15125.118.0.1 to 125.119.255.254125.119.255.255131,070
189125.120.0.0/15125.120.0.1 to 125.121.255.254125.121.255.255131,070
190125.122.0.0/15125.122.0.1 to 125.123.255.254125.123.255.255131,070
191125.124.0.0/15125.124.0.1 to 125.125.255.254125.125.255.255131,070
192125.126.0.0/15125.126.0.1 to 125.127.255.254125.127.255.255131,070
193125.128.0.0/15125.128.0.1 to 125.129.255.254125.129.255.255131,070
194125.130.0.0/15125.130.0.1 to 125.131.255.254125.131.255.255131,070
195125.132.0.0/15125.132.0.1 to 125.133.255.254125.133.255.255131,070
196125.134.0.0/15125.134.0.1 to 125.135.255.254125.135.255.255131,070
197125.136.0.0/15125.136.0.1 to 125.137.255.254125.137.255.255131,070
198125.138.0.0/15125.138.0.1 to 125.139.255.254125.139.255.255131,070
199125.140.0.0/15125.140.0.1 to 125.141.255.254125.141.255.255131,070
200125.142.0.0/15125.142.0.1 to 125.143.255.254125.143.255.255131,070
201125.144.0.0/15125.144.0.1 to 125.145.255.254125.145.255.255131,070
202125.146.0.0/15125.146.0.1 to 125.147.255.254125.147.255.255131,070
203125.148.0.0/15125.148.0.1 to 125.149.255.254125.149.255.255131,070
204125.150.0.0/15125.150.0.1 to 125.151.255.254125.151.255.255131,070
205125.152.0.0/15125.152.0.1 to 125.153.255.254125.153.255.255131,070
206125.154.0.0/15125.154.0.1 to 125.155.255.254125.155.255.255131,070
207125.156.0.0/15125.156.0.1 to 125.157.255.254125.157.255.255131,070
208125.158.0.0/15125.158.0.1 to 125.159.255.254125.159.255.255131,070
209125.160.0.0/15125.160.0.1 to 125.161.255.254125.161.255.255131,070
210125.162.0.0/15125.162.0.1 to 125.163.255.254125.163.255.255131,070
211125.164.0.0/15125.164.0.1 to 125.165.255.254125.165.255.255131,070
212125.166.0.0/15125.166.0.1 to 125.167.255.254125.167.255.255131,070
213125.168.0.0/15125.168.0.1 to 125.169.255.254125.169.255.255131,070
214125.170.0.0/15125.170.0.1 to 125.171.255.254125.171.255.255131,070
215125.172.0.0/15125.172.0.1 to 125.173.255.254125.173.255.255131,070
216125.174.0.0/15125.174.0.1 to 125.175.255.254125.175.255.255131,070
217125.176.0.0/15125.176.0.1 to 125.177.255.254125.177.255.255131,070
218125.178.0.0/15125.178.0.1 to 125.179.255.254125.179.255.255131,070
219125.180.0.0/15125.180.0.1 to 125.181.255.254125.181.255.255131,070
220125.182.0.0/15125.182.0.1 to 125.183.255.254125.183.255.255131,070
221125.184.0.0/15125.184.0.1 to 125.185.255.254125.185.255.255131,070
222125.186.0.0/15125.186.0.1 to 125.187.255.254125.187.255.255131,070
223125.188.0.0/15125.188.0.1 to 125.189.255.254125.189.255.255131,070
224125.190.0.0/15125.190.0.1 to 125.191.255.254125.191.255.255131,070
225125.192.0.0/15125.192.0.1 to 125.193.255.254125.193.255.255131,070
226125.194.0.0/15125.194.0.1 to 125.195.255.254125.195.255.255131,070
227125.196.0.0/15125.196.0.1 to 125.197.255.254125.197.255.255131,070
228125.198.0.0/15125.198.0.1 to 125.199.255.254125.199.255.255131,070
229125.200.0.0/15125.200.0.1 to 125.201.255.254125.201.255.255131,070
230125.202.0.0/15125.202.0.1 to 125.203.255.254125.203.255.255131,070
231125.204.0.0/15125.204.0.1 to 125.205.255.254125.205.255.255131,070
232125.206.0.0/15125.206.0.1 to 125.207.255.254125.207.255.255131,070
233125.208.0.0/15125.208.0.1 to 125.209.255.254125.209.255.255131,070
234125.210.0.0/15125.210.0.1 to 125.211.255.254125.211.255.255131,070
235125.212.0.0/15125.212.0.1 to 125.213.255.254125.213.255.255131,070
236125.214.0.0/15125.214.0.1 to 125.215.255.254125.215.255.255131,070
237125.216.0.0/15125.216.0.1 to 125.217.255.254125.217.255.255131,070
238125.218.0.0/15125.218.0.1 to 125.219.255.254125.219.255.255131,070
239125.220.0.0/15125.220.0.1 to 125.221.255.254125.221.255.255131,070
240125.222.0.0/15125.222.0.1 to 125.223.255.254125.223.255.255131,070
241125.224.0.0/15125.224.0.1 to 125.225.255.254125.225.255.255131,070
242125.226.0.0/15125.226.0.1 to 125.227.255.254125.227.255.255131,070
243125.228.0.0/15125.228.0.1 to 125.229.255.254125.229.255.255131,070
244125.230.0.0/15125.230.0.1 to 125.231.255.254125.231.255.255131,070
245125.232.0.0/15125.232.0.1 to 125.233.255.254125.233.255.255131,070
246125.234.0.0/15125.234.0.1 to 125.235.255.254125.235.255.255131,070
247125.236.0.0/15125.236.0.1 to 125.237.255.254125.237.255.255131,070
248125.238.0.0/15125.238.0.1 to 125.239.255.254125.239.255.255131,070
249125.240.0.0/15125.240.0.1 to 125.241.255.254125.241.255.255131,070
250125.242.0.0/15125.242.0.1 to 125.243.255.254125.243.255.255131,070
251125.244.0.0/15125.244.0.1 to 125.245.255.254125.245.255.255131,070
252125.246.0.0/15125.246.0.1 to 125.247.255.254125.247.255.255131,070
253125.248.0.0/15125.248.0.1 to 125.249.255.254125.249.255.255131,070
254125.250.0.0/15125.250.0.1 to 125.251.255.254125.251.255.255131,070
255125.252.0.0/15125.252.0.1 to 125.253.255.254125.253.255.255131,070
256125.254.0.0/15125.254.0.1 to 125.255.255.254125.255.255.255131,070

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.