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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.

Network221.80.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
221.80.0.0
Broadcast address
221.87.255.255
First usable
221.80.0.1
Last usable
221.87.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Public public
Old class
C (default /24)
As numbers
Hex DD500000 · Integer 3713007616 to 3713531903
Reverse DNS zones
80.221.in-addr.arpa
81.221.in-addr.arpa
82.221.in-addr.arpa
83.221.in-addr.arpa
84.221.in-addr.arpa
85.221.in-addr.arpa
86.221.in-addr.arpa
87.221.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11011101.01010000.00000000.00000000221.80.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network11011101.01010000.00000000.00000000221.80.0.0
Broadcast11011101.01010111.11111111.11111111221.87.255.255
Split into smaller subnets/22
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

221.80.0.0/13 makes 512 subnets of /22; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1221.80.0.0/22221.80.0.1 to 221.80.3.254221.80.3.2551,022
2221.80.4.0/22221.80.4.1 to 221.80.7.254221.80.7.2551,022
3221.80.8.0/22221.80.8.1 to 221.80.11.254221.80.11.2551,022
4221.80.12.0/22221.80.12.1 to 221.80.15.254221.80.15.2551,022
5221.80.16.0/22221.80.16.1 to 221.80.19.254221.80.19.2551,022
6221.80.20.0/22221.80.20.1 to 221.80.23.254221.80.23.2551,022
7221.80.24.0/22221.80.24.1 to 221.80.27.254221.80.27.2551,022
8221.80.28.0/22221.80.28.1 to 221.80.31.254221.80.31.2551,022
9221.80.32.0/22221.80.32.1 to 221.80.35.254221.80.35.2551,022
10221.80.36.0/22221.80.36.1 to 221.80.39.254221.80.39.2551,022
11221.80.40.0/22221.80.40.1 to 221.80.43.254221.80.43.2551,022
12221.80.44.0/22221.80.44.1 to 221.80.47.254221.80.47.2551,022
13221.80.48.0/22221.80.48.1 to 221.80.51.254221.80.51.2551,022
14221.80.52.0/22221.80.52.1 to 221.80.55.254221.80.55.2551,022
15221.80.56.0/22221.80.56.1 to 221.80.59.254221.80.59.2551,022
16221.80.60.0/22221.80.60.1 to 221.80.63.254221.80.63.2551,022
17221.80.64.0/22221.80.64.1 to 221.80.67.254221.80.67.2551,022
18221.80.68.0/22221.80.68.1 to 221.80.71.254221.80.71.2551,022
19221.80.72.0/22221.80.72.1 to 221.80.75.254221.80.75.2551,022
20221.80.76.0/22221.80.76.1 to 221.80.79.254221.80.79.2551,022
21221.80.80.0/22221.80.80.1 to 221.80.83.254221.80.83.2551,022
22221.80.84.0/22221.80.84.1 to 221.80.87.254221.80.87.2551,022
23221.80.88.0/22221.80.88.1 to 221.80.91.254221.80.91.2551,022
24221.80.92.0/22221.80.92.1 to 221.80.95.254221.80.95.2551,022
25221.80.96.0/22221.80.96.1 to 221.80.99.254221.80.99.2551,022
26221.80.100.0/22221.80.100.1 to 221.80.103.254221.80.103.2551,022
27221.80.104.0/22221.80.104.1 to 221.80.107.254221.80.107.2551,022
28221.80.108.0/22221.80.108.1 to 221.80.111.254221.80.111.2551,022
29221.80.112.0/22221.80.112.1 to 221.80.115.254221.80.115.2551,022
30221.80.116.0/22221.80.116.1 to 221.80.119.254221.80.119.2551,022
31221.80.120.0/22221.80.120.1 to 221.80.123.254221.80.123.2551,022
32221.80.124.0/22221.80.124.1 to 221.80.127.254221.80.127.2551,022
33221.80.128.0/22221.80.128.1 to 221.80.131.254221.80.131.2551,022
34221.80.132.0/22221.80.132.1 to 221.80.135.254221.80.135.2551,022
35221.80.136.0/22221.80.136.1 to 221.80.139.254221.80.139.2551,022
36221.80.140.0/22221.80.140.1 to 221.80.143.254221.80.143.2551,022
37221.80.144.0/22221.80.144.1 to 221.80.147.254221.80.147.2551,022
38221.80.148.0/22221.80.148.1 to 221.80.151.254221.80.151.2551,022
39221.80.152.0/22221.80.152.1 to 221.80.155.254221.80.155.2551,022
40221.80.156.0/22221.80.156.1 to 221.80.159.254221.80.159.2551,022
41221.80.160.0/22221.80.160.1 to 221.80.163.254221.80.163.2551,022
42221.80.164.0/22221.80.164.1 to 221.80.167.254221.80.167.2551,022
43221.80.168.0/22221.80.168.1 to 221.80.171.254221.80.171.2551,022
44221.80.172.0/22221.80.172.1 to 221.80.175.254221.80.175.2551,022
45221.80.176.0/22221.80.176.1 to 221.80.179.254221.80.179.2551,022
46221.80.180.0/22221.80.180.1 to 221.80.183.254221.80.183.2551,022
47221.80.184.0/22221.80.184.1 to 221.80.187.254221.80.187.2551,022
48221.80.188.0/22221.80.188.1 to 221.80.191.254221.80.191.2551,022
49221.80.192.0/22221.80.192.1 to 221.80.195.254221.80.195.2551,022
50221.80.196.0/22221.80.196.1 to 221.80.199.254221.80.199.2551,022
51221.80.200.0/22221.80.200.1 to 221.80.203.254221.80.203.2551,022
52221.80.204.0/22221.80.204.1 to 221.80.207.254221.80.207.2551,022
53221.80.208.0/22221.80.208.1 to 221.80.211.254221.80.211.2551,022
54221.80.212.0/22221.80.212.1 to 221.80.215.254221.80.215.2551,022
55221.80.216.0/22221.80.216.1 to 221.80.219.254221.80.219.2551,022
56221.80.220.0/22221.80.220.1 to 221.80.223.254221.80.223.2551,022
57221.80.224.0/22221.80.224.1 to 221.80.227.254221.80.227.2551,022
58221.80.228.0/22221.80.228.1 to 221.80.231.254221.80.231.2551,022
59221.80.232.0/22221.80.232.1 to 221.80.235.254221.80.235.2551,022
60221.80.236.0/22221.80.236.1 to 221.80.239.254221.80.239.2551,022
61221.80.240.0/22221.80.240.1 to 221.80.243.254221.80.243.2551,022
62221.80.244.0/22221.80.244.1 to 221.80.247.254221.80.247.2551,022
63221.80.248.0/22221.80.248.1 to 221.80.251.254221.80.251.2551,022
64221.80.252.0/22221.80.252.1 to 221.80.255.254221.80.255.2551,022
65221.81.0.0/22221.81.0.1 to 221.81.3.254221.81.3.2551,022
66221.81.4.0/22221.81.4.1 to 221.81.7.254221.81.7.2551,022
67221.81.8.0/22221.81.8.1 to 221.81.11.254221.81.11.2551,022
68221.81.12.0/22221.81.12.1 to 221.81.15.254221.81.15.2551,022
69221.81.16.0/22221.81.16.1 to 221.81.19.254221.81.19.2551,022
70221.81.20.0/22221.81.20.1 to 221.81.23.254221.81.23.2551,022
71221.81.24.0/22221.81.24.1 to 221.81.27.254221.81.27.2551,022
72221.81.28.0/22221.81.28.1 to 221.81.31.254221.81.31.2551,022
73221.81.32.0/22221.81.32.1 to 221.81.35.254221.81.35.2551,022
74221.81.36.0/22221.81.36.1 to 221.81.39.254221.81.39.2551,022
75221.81.40.0/22221.81.40.1 to 221.81.43.254221.81.43.2551,022
76221.81.44.0/22221.81.44.1 to 221.81.47.254221.81.47.2551,022
77221.81.48.0/22221.81.48.1 to 221.81.51.254221.81.51.2551,022
78221.81.52.0/22221.81.52.1 to 221.81.55.254221.81.55.2551,022
79221.81.56.0/22221.81.56.1 to 221.81.59.254221.81.59.2551,022
80221.81.60.0/22221.81.60.1 to 221.81.63.254221.81.63.2551,022
81221.81.64.0/22221.81.64.1 to 221.81.67.254221.81.67.2551,022
82221.81.68.0/22221.81.68.1 to 221.81.71.254221.81.71.2551,022
83221.81.72.0/22221.81.72.1 to 221.81.75.254221.81.75.2551,022
84221.81.76.0/22221.81.76.1 to 221.81.79.254221.81.79.2551,022
85221.81.80.0/22221.81.80.1 to 221.81.83.254221.81.83.2551,022
86221.81.84.0/22221.81.84.1 to 221.81.87.254221.81.87.2551,022
87221.81.88.0/22221.81.88.1 to 221.81.91.254221.81.91.2551,022
88221.81.92.0/22221.81.92.1 to 221.81.95.254221.81.95.2551,022
89221.81.96.0/22221.81.96.1 to 221.81.99.254221.81.99.2551,022
90221.81.100.0/22221.81.100.1 to 221.81.103.254221.81.103.2551,022
91221.81.104.0/22221.81.104.1 to 221.81.107.254221.81.107.2551,022
92221.81.108.0/22221.81.108.1 to 221.81.111.254221.81.111.2551,022
93221.81.112.0/22221.81.112.1 to 221.81.115.254221.81.115.2551,022
94221.81.116.0/22221.81.116.1 to 221.81.119.254221.81.119.2551,022
95221.81.120.0/22221.81.120.1 to 221.81.123.254221.81.123.2551,022
96221.81.124.0/22221.81.124.1 to 221.81.127.254221.81.127.2551,022
97221.81.128.0/22221.81.128.1 to 221.81.131.254221.81.131.2551,022
98221.81.132.0/22221.81.132.1 to 221.81.135.254221.81.135.2551,022
99221.81.136.0/22221.81.136.1 to 221.81.139.254221.81.139.2551,022
100221.81.140.0/22221.81.140.1 to 221.81.143.254221.81.143.2551,022
101221.81.144.0/22221.81.144.1 to 221.81.147.254221.81.147.2551,022
102221.81.148.0/22221.81.148.1 to 221.81.151.254221.81.151.2551,022
103221.81.152.0/22221.81.152.1 to 221.81.155.254221.81.155.2551,022
104221.81.156.0/22221.81.156.1 to 221.81.159.254221.81.159.2551,022
105221.81.160.0/22221.81.160.1 to 221.81.163.254221.81.163.2551,022
106221.81.164.0/22221.81.164.1 to 221.81.167.254221.81.167.2551,022
107221.81.168.0/22221.81.168.1 to 221.81.171.254221.81.171.2551,022
108221.81.172.0/22221.81.172.1 to 221.81.175.254221.81.175.2551,022
109221.81.176.0/22221.81.176.1 to 221.81.179.254221.81.179.2551,022
110221.81.180.0/22221.81.180.1 to 221.81.183.254221.81.183.2551,022
111221.81.184.0/22221.81.184.1 to 221.81.187.254221.81.187.2551,022
112221.81.188.0/22221.81.188.1 to 221.81.191.254221.81.191.2551,022
113221.81.192.0/22221.81.192.1 to 221.81.195.254221.81.195.2551,022
114221.81.196.0/22221.81.196.1 to 221.81.199.254221.81.199.2551,022
115221.81.200.0/22221.81.200.1 to 221.81.203.254221.81.203.2551,022
116221.81.204.0/22221.81.204.1 to 221.81.207.254221.81.207.2551,022
117221.81.208.0/22221.81.208.1 to 221.81.211.254221.81.211.2551,022
118221.81.212.0/22221.81.212.1 to 221.81.215.254221.81.215.2551,022
119221.81.216.0/22221.81.216.1 to 221.81.219.254221.81.219.2551,022
120221.81.220.0/22221.81.220.1 to 221.81.223.254221.81.223.2551,022
121221.81.224.0/22221.81.224.1 to 221.81.227.254221.81.227.2551,022
122221.81.228.0/22221.81.228.1 to 221.81.231.254221.81.231.2551,022
123221.81.232.0/22221.81.232.1 to 221.81.235.254221.81.235.2551,022
124221.81.236.0/22221.81.236.1 to 221.81.239.254221.81.239.2551,022
125221.81.240.0/22221.81.240.1 to 221.81.243.254221.81.243.2551,022
126221.81.244.0/22221.81.244.1 to 221.81.247.254221.81.247.2551,022
127221.81.248.0/22221.81.248.1 to 221.81.251.254221.81.251.2551,022
128221.81.252.0/22221.81.252.1 to 221.81.255.254221.81.255.2551,022
129221.82.0.0/22221.82.0.1 to 221.82.3.254221.82.3.2551,022
130221.82.4.0/22221.82.4.1 to 221.82.7.254221.82.7.2551,022
131221.82.8.0/22221.82.8.1 to 221.82.11.254221.82.11.2551,022
132221.82.12.0/22221.82.12.1 to 221.82.15.254221.82.15.2551,022
133221.82.16.0/22221.82.16.1 to 221.82.19.254221.82.19.2551,022
134221.82.20.0/22221.82.20.1 to 221.82.23.254221.82.23.2551,022
135221.82.24.0/22221.82.24.1 to 221.82.27.254221.82.27.2551,022
136221.82.28.0/22221.82.28.1 to 221.82.31.254221.82.31.2551,022
137221.82.32.0/22221.82.32.1 to 221.82.35.254221.82.35.2551,022
138221.82.36.0/22221.82.36.1 to 221.82.39.254221.82.39.2551,022
139221.82.40.0/22221.82.40.1 to 221.82.43.254221.82.43.2551,022
140221.82.44.0/22221.82.44.1 to 221.82.47.254221.82.47.2551,022
141221.82.48.0/22221.82.48.1 to 221.82.51.254221.82.51.2551,022
142221.82.52.0/22221.82.52.1 to 221.82.55.254221.82.55.2551,022
143221.82.56.0/22221.82.56.1 to 221.82.59.254221.82.59.2551,022
144221.82.60.0/22221.82.60.1 to 221.82.63.254221.82.63.2551,022
145221.82.64.0/22221.82.64.1 to 221.82.67.254221.82.67.2551,022
146221.82.68.0/22221.82.68.1 to 221.82.71.254221.82.71.2551,022
147221.82.72.0/22221.82.72.1 to 221.82.75.254221.82.75.2551,022
148221.82.76.0/22221.82.76.1 to 221.82.79.254221.82.79.2551,022
149221.82.80.0/22221.82.80.1 to 221.82.83.254221.82.83.2551,022
150221.82.84.0/22221.82.84.1 to 221.82.87.254221.82.87.2551,022
151221.82.88.0/22221.82.88.1 to 221.82.91.254221.82.91.2551,022
152221.82.92.0/22221.82.92.1 to 221.82.95.254221.82.95.2551,022
153221.82.96.0/22221.82.96.1 to 221.82.99.254221.82.99.2551,022
154221.82.100.0/22221.82.100.1 to 221.82.103.254221.82.103.2551,022
155221.82.104.0/22221.82.104.1 to 221.82.107.254221.82.107.2551,022
156221.82.108.0/22221.82.108.1 to 221.82.111.254221.82.111.2551,022
157221.82.112.0/22221.82.112.1 to 221.82.115.254221.82.115.2551,022
158221.82.116.0/22221.82.116.1 to 221.82.119.254221.82.119.2551,022
159221.82.120.0/22221.82.120.1 to 221.82.123.254221.82.123.2551,022
160221.82.124.0/22221.82.124.1 to 221.82.127.254221.82.127.2551,022
161221.82.128.0/22221.82.128.1 to 221.82.131.254221.82.131.2551,022
162221.82.132.0/22221.82.132.1 to 221.82.135.254221.82.135.2551,022
163221.82.136.0/22221.82.136.1 to 221.82.139.254221.82.139.2551,022
164221.82.140.0/22221.82.140.1 to 221.82.143.254221.82.143.2551,022
165221.82.144.0/22221.82.144.1 to 221.82.147.254221.82.147.2551,022
166221.82.148.0/22221.82.148.1 to 221.82.151.254221.82.151.2551,022
167221.82.152.0/22221.82.152.1 to 221.82.155.254221.82.155.2551,022
168221.82.156.0/22221.82.156.1 to 221.82.159.254221.82.159.2551,022
169221.82.160.0/22221.82.160.1 to 221.82.163.254221.82.163.2551,022
170221.82.164.0/22221.82.164.1 to 221.82.167.254221.82.167.2551,022
171221.82.168.0/22221.82.168.1 to 221.82.171.254221.82.171.2551,022
172221.82.172.0/22221.82.172.1 to 221.82.175.254221.82.175.2551,022
173221.82.176.0/22221.82.176.1 to 221.82.179.254221.82.179.2551,022
174221.82.180.0/22221.82.180.1 to 221.82.183.254221.82.183.2551,022
175221.82.184.0/22221.82.184.1 to 221.82.187.254221.82.187.2551,022
176221.82.188.0/22221.82.188.1 to 221.82.191.254221.82.191.2551,022
177221.82.192.0/22221.82.192.1 to 221.82.195.254221.82.195.2551,022
178221.82.196.0/22221.82.196.1 to 221.82.199.254221.82.199.2551,022
179221.82.200.0/22221.82.200.1 to 221.82.203.254221.82.203.2551,022
180221.82.204.0/22221.82.204.1 to 221.82.207.254221.82.207.2551,022
181221.82.208.0/22221.82.208.1 to 221.82.211.254221.82.211.2551,022
182221.82.212.0/22221.82.212.1 to 221.82.215.254221.82.215.2551,022
183221.82.216.0/22221.82.216.1 to 221.82.219.254221.82.219.2551,022
184221.82.220.0/22221.82.220.1 to 221.82.223.254221.82.223.2551,022
185221.82.224.0/22221.82.224.1 to 221.82.227.254221.82.227.2551,022
186221.82.228.0/22221.82.228.1 to 221.82.231.254221.82.231.2551,022
187221.82.232.0/22221.82.232.1 to 221.82.235.254221.82.235.2551,022
188221.82.236.0/22221.82.236.1 to 221.82.239.254221.82.239.2551,022
189221.82.240.0/22221.82.240.1 to 221.82.243.254221.82.243.2551,022
190221.82.244.0/22221.82.244.1 to 221.82.247.254221.82.247.2551,022
191221.82.248.0/22221.82.248.1 to 221.82.251.254221.82.251.2551,022
192221.82.252.0/22221.82.252.1 to 221.82.255.254221.82.255.2551,022
193221.83.0.0/22221.83.0.1 to 221.83.3.254221.83.3.2551,022
194221.83.4.0/22221.83.4.1 to 221.83.7.254221.83.7.2551,022
195221.83.8.0/22221.83.8.1 to 221.83.11.254221.83.11.2551,022
196221.83.12.0/22221.83.12.1 to 221.83.15.254221.83.15.2551,022
197221.83.16.0/22221.83.16.1 to 221.83.19.254221.83.19.2551,022
198221.83.20.0/22221.83.20.1 to 221.83.23.254221.83.23.2551,022
199221.83.24.0/22221.83.24.1 to 221.83.27.254221.83.27.2551,022
200221.83.28.0/22221.83.28.1 to 221.83.31.254221.83.31.2551,022
201221.83.32.0/22221.83.32.1 to 221.83.35.254221.83.35.2551,022
202221.83.36.0/22221.83.36.1 to 221.83.39.254221.83.39.2551,022
203221.83.40.0/22221.83.40.1 to 221.83.43.254221.83.43.2551,022
204221.83.44.0/22221.83.44.1 to 221.83.47.254221.83.47.2551,022
205221.83.48.0/22221.83.48.1 to 221.83.51.254221.83.51.2551,022
206221.83.52.0/22221.83.52.1 to 221.83.55.254221.83.55.2551,022
207221.83.56.0/22221.83.56.1 to 221.83.59.254221.83.59.2551,022
208221.83.60.0/22221.83.60.1 to 221.83.63.254221.83.63.2551,022
209221.83.64.0/22221.83.64.1 to 221.83.67.254221.83.67.2551,022
210221.83.68.0/22221.83.68.1 to 221.83.71.254221.83.71.2551,022
211221.83.72.0/22221.83.72.1 to 221.83.75.254221.83.75.2551,022
212221.83.76.0/22221.83.76.1 to 221.83.79.254221.83.79.2551,022
213221.83.80.0/22221.83.80.1 to 221.83.83.254221.83.83.2551,022
214221.83.84.0/22221.83.84.1 to 221.83.87.254221.83.87.2551,022
215221.83.88.0/22221.83.88.1 to 221.83.91.254221.83.91.2551,022
216221.83.92.0/22221.83.92.1 to 221.83.95.254221.83.95.2551,022
217221.83.96.0/22221.83.96.1 to 221.83.99.254221.83.99.2551,022
218221.83.100.0/22221.83.100.1 to 221.83.103.254221.83.103.2551,022
219221.83.104.0/22221.83.104.1 to 221.83.107.254221.83.107.2551,022
220221.83.108.0/22221.83.108.1 to 221.83.111.254221.83.111.2551,022
221221.83.112.0/22221.83.112.1 to 221.83.115.254221.83.115.2551,022
222221.83.116.0/22221.83.116.1 to 221.83.119.254221.83.119.2551,022
223221.83.120.0/22221.83.120.1 to 221.83.123.254221.83.123.2551,022
224221.83.124.0/22221.83.124.1 to 221.83.127.254221.83.127.2551,022
225221.83.128.0/22221.83.128.1 to 221.83.131.254221.83.131.2551,022
226221.83.132.0/22221.83.132.1 to 221.83.135.254221.83.135.2551,022
227221.83.136.0/22221.83.136.1 to 221.83.139.254221.83.139.2551,022
228221.83.140.0/22221.83.140.1 to 221.83.143.254221.83.143.2551,022
229221.83.144.0/22221.83.144.1 to 221.83.147.254221.83.147.2551,022
230221.83.148.0/22221.83.148.1 to 221.83.151.254221.83.151.2551,022
231221.83.152.0/22221.83.152.1 to 221.83.155.254221.83.155.2551,022
232221.83.156.0/22221.83.156.1 to 221.83.159.254221.83.159.2551,022
233221.83.160.0/22221.83.160.1 to 221.83.163.254221.83.163.2551,022
234221.83.164.0/22221.83.164.1 to 221.83.167.254221.83.167.2551,022
235221.83.168.0/22221.83.168.1 to 221.83.171.254221.83.171.2551,022
236221.83.172.0/22221.83.172.1 to 221.83.175.254221.83.175.2551,022
237221.83.176.0/22221.83.176.1 to 221.83.179.254221.83.179.2551,022
238221.83.180.0/22221.83.180.1 to 221.83.183.254221.83.183.2551,022
239221.83.184.0/22221.83.184.1 to 221.83.187.254221.83.187.2551,022
240221.83.188.0/22221.83.188.1 to 221.83.191.254221.83.191.2551,022
241221.83.192.0/22221.83.192.1 to 221.83.195.254221.83.195.2551,022
242221.83.196.0/22221.83.196.1 to 221.83.199.254221.83.199.2551,022
243221.83.200.0/22221.83.200.1 to 221.83.203.254221.83.203.2551,022
244221.83.204.0/22221.83.204.1 to 221.83.207.254221.83.207.2551,022
245221.83.208.0/22221.83.208.1 to 221.83.211.254221.83.211.2551,022
246221.83.212.0/22221.83.212.1 to 221.83.215.254221.83.215.2551,022
247221.83.216.0/22221.83.216.1 to 221.83.219.254221.83.219.2551,022
248221.83.220.0/22221.83.220.1 to 221.83.223.254221.83.223.2551,022
249221.83.224.0/22221.83.224.1 to 221.83.227.254221.83.227.2551,022
250221.83.228.0/22221.83.228.1 to 221.83.231.254221.83.231.2551,022
251221.83.232.0/22221.83.232.1 to 221.83.235.254221.83.235.2551,022
252221.83.236.0/22221.83.236.1 to 221.83.239.254221.83.239.2551,022
253221.83.240.0/22221.83.240.1 to 221.83.243.254221.83.243.2551,022
254221.83.244.0/22221.83.244.1 to 221.83.247.254221.83.247.2551,022
255221.83.248.0/22221.83.248.1 to 221.83.251.254221.83.251.2551,022
256221.83.252.0/22221.83.252.1 to 221.83.255.254221.83.255.2551,022

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.