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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.

Network243.0.0.0/14
Usable hosts262,142
Subnet mask255.252.0.0
Addresses262,144
Network address
243.0.0.0
Broadcast address
243.3.255.255
First usable
243.0.0.1
Last usable
243.3.255.254
Usable hosts
262,142 (262,144 less the network and broadcast addresses)
Subnet mask
255.252.0.0
Wildcard mask
0.3.255.255 (Cisco ACLs, OSPF)
Prefix length
/14
Type
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex F3000000 · Integer 4076863488 to 4077125631
Reverse DNS zones
0.243.in-addr.arpa
1.243.in-addr.arpa
2.243.in-addr.arpa
3.243.in-addr.arpa
/14 is not on a 8-bit boundary, so it takes 4 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11110011.00000000.00000000.00000000243.0.0.0
Subnet mask11111111.11111100.00000000.00000000255.252.0.0
Network11110011.00000000.00000000.00000000243.0.0.0
Broadcast11110011.00000011.11111111.11111111243.3.255.255
Split into smaller subnets/22
/15 (2)/16 (4)/17 (8)/18 (16)/19 (32)/20 (64)/21 (128)/22 (256)/23 (512)/24 (1,024)/25 (2,048)/26 (4,096)

243.0.0.0/14 makes 256 subnets of /22.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1243.0.0.0/22243.0.0.1 to 243.0.3.254243.0.3.2551,022
2243.0.4.0/22243.0.4.1 to 243.0.7.254243.0.7.2551,022
3243.0.8.0/22243.0.8.1 to 243.0.11.254243.0.11.2551,022
4243.0.12.0/22243.0.12.1 to 243.0.15.254243.0.15.2551,022
5243.0.16.0/22243.0.16.1 to 243.0.19.254243.0.19.2551,022
6243.0.20.0/22243.0.20.1 to 243.0.23.254243.0.23.2551,022
7243.0.24.0/22243.0.24.1 to 243.0.27.254243.0.27.2551,022
8243.0.28.0/22243.0.28.1 to 243.0.31.254243.0.31.2551,022
9243.0.32.0/22243.0.32.1 to 243.0.35.254243.0.35.2551,022
10243.0.36.0/22243.0.36.1 to 243.0.39.254243.0.39.2551,022
11243.0.40.0/22243.0.40.1 to 243.0.43.254243.0.43.2551,022
12243.0.44.0/22243.0.44.1 to 243.0.47.254243.0.47.2551,022
13243.0.48.0/22243.0.48.1 to 243.0.51.254243.0.51.2551,022
14243.0.52.0/22243.0.52.1 to 243.0.55.254243.0.55.2551,022
15243.0.56.0/22243.0.56.1 to 243.0.59.254243.0.59.2551,022
16243.0.60.0/22243.0.60.1 to 243.0.63.254243.0.63.2551,022
17243.0.64.0/22243.0.64.1 to 243.0.67.254243.0.67.2551,022
18243.0.68.0/22243.0.68.1 to 243.0.71.254243.0.71.2551,022
19243.0.72.0/22243.0.72.1 to 243.0.75.254243.0.75.2551,022
20243.0.76.0/22243.0.76.1 to 243.0.79.254243.0.79.2551,022
21243.0.80.0/22243.0.80.1 to 243.0.83.254243.0.83.2551,022
22243.0.84.0/22243.0.84.1 to 243.0.87.254243.0.87.2551,022
23243.0.88.0/22243.0.88.1 to 243.0.91.254243.0.91.2551,022
24243.0.92.0/22243.0.92.1 to 243.0.95.254243.0.95.2551,022
25243.0.96.0/22243.0.96.1 to 243.0.99.254243.0.99.2551,022
26243.0.100.0/22243.0.100.1 to 243.0.103.254243.0.103.2551,022
27243.0.104.0/22243.0.104.1 to 243.0.107.254243.0.107.2551,022
28243.0.108.0/22243.0.108.1 to 243.0.111.254243.0.111.2551,022
29243.0.112.0/22243.0.112.1 to 243.0.115.254243.0.115.2551,022
30243.0.116.0/22243.0.116.1 to 243.0.119.254243.0.119.2551,022
31243.0.120.0/22243.0.120.1 to 243.0.123.254243.0.123.2551,022
32243.0.124.0/22243.0.124.1 to 243.0.127.254243.0.127.2551,022
33243.0.128.0/22243.0.128.1 to 243.0.131.254243.0.131.2551,022
34243.0.132.0/22243.0.132.1 to 243.0.135.254243.0.135.2551,022
35243.0.136.0/22243.0.136.1 to 243.0.139.254243.0.139.2551,022
36243.0.140.0/22243.0.140.1 to 243.0.143.254243.0.143.2551,022
37243.0.144.0/22243.0.144.1 to 243.0.147.254243.0.147.2551,022
38243.0.148.0/22243.0.148.1 to 243.0.151.254243.0.151.2551,022
39243.0.152.0/22243.0.152.1 to 243.0.155.254243.0.155.2551,022
40243.0.156.0/22243.0.156.1 to 243.0.159.254243.0.159.2551,022
41243.0.160.0/22243.0.160.1 to 243.0.163.254243.0.163.2551,022
42243.0.164.0/22243.0.164.1 to 243.0.167.254243.0.167.2551,022
43243.0.168.0/22243.0.168.1 to 243.0.171.254243.0.171.2551,022
44243.0.172.0/22243.0.172.1 to 243.0.175.254243.0.175.2551,022
45243.0.176.0/22243.0.176.1 to 243.0.179.254243.0.179.2551,022
46243.0.180.0/22243.0.180.1 to 243.0.183.254243.0.183.2551,022
47243.0.184.0/22243.0.184.1 to 243.0.187.254243.0.187.2551,022
48243.0.188.0/22243.0.188.1 to 243.0.191.254243.0.191.2551,022
49243.0.192.0/22243.0.192.1 to 243.0.195.254243.0.195.2551,022
50243.0.196.0/22243.0.196.1 to 243.0.199.254243.0.199.2551,022
51243.0.200.0/22243.0.200.1 to 243.0.203.254243.0.203.2551,022
52243.0.204.0/22243.0.204.1 to 243.0.207.254243.0.207.2551,022
53243.0.208.0/22243.0.208.1 to 243.0.211.254243.0.211.2551,022
54243.0.212.0/22243.0.212.1 to 243.0.215.254243.0.215.2551,022
55243.0.216.0/22243.0.216.1 to 243.0.219.254243.0.219.2551,022
56243.0.220.0/22243.0.220.1 to 243.0.223.254243.0.223.2551,022
57243.0.224.0/22243.0.224.1 to 243.0.227.254243.0.227.2551,022
58243.0.228.0/22243.0.228.1 to 243.0.231.254243.0.231.2551,022
59243.0.232.0/22243.0.232.1 to 243.0.235.254243.0.235.2551,022
60243.0.236.0/22243.0.236.1 to 243.0.239.254243.0.239.2551,022
61243.0.240.0/22243.0.240.1 to 243.0.243.254243.0.243.2551,022
62243.0.244.0/22243.0.244.1 to 243.0.247.254243.0.247.2551,022
63243.0.248.0/22243.0.248.1 to 243.0.251.254243.0.251.2551,022
64243.0.252.0/22243.0.252.1 to 243.0.255.254243.0.255.2551,022
65243.1.0.0/22243.1.0.1 to 243.1.3.254243.1.3.2551,022
66243.1.4.0/22243.1.4.1 to 243.1.7.254243.1.7.2551,022
67243.1.8.0/22243.1.8.1 to 243.1.11.254243.1.11.2551,022
68243.1.12.0/22243.1.12.1 to 243.1.15.254243.1.15.2551,022
69243.1.16.0/22243.1.16.1 to 243.1.19.254243.1.19.2551,022
70243.1.20.0/22243.1.20.1 to 243.1.23.254243.1.23.2551,022
71243.1.24.0/22243.1.24.1 to 243.1.27.254243.1.27.2551,022
72243.1.28.0/22243.1.28.1 to 243.1.31.254243.1.31.2551,022
73243.1.32.0/22243.1.32.1 to 243.1.35.254243.1.35.2551,022
74243.1.36.0/22243.1.36.1 to 243.1.39.254243.1.39.2551,022
75243.1.40.0/22243.1.40.1 to 243.1.43.254243.1.43.2551,022
76243.1.44.0/22243.1.44.1 to 243.1.47.254243.1.47.2551,022
77243.1.48.0/22243.1.48.1 to 243.1.51.254243.1.51.2551,022
78243.1.52.0/22243.1.52.1 to 243.1.55.254243.1.55.2551,022
79243.1.56.0/22243.1.56.1 to 243.1.59.254243.1.59.2551,022
80243.1.60.0/22243.1.60.1 to 243.1.63.254243.1.63.2551,022
81243.1.64.0/22243.1.64.1 to 243.1.67.254243.1.67.2551,022
82243.1.68.0/22243.1.68.1 to 243.1.71.254243.1.71.2551,022
83243.1.72.0/22243.1.72.1 to 243.1.75.254243.1.75.2551,022
84243.1.76.0/22243.1.76.1 to 243.1.79.254243.1.79.2551,022
85243.1.80.0/22243.1.80.1 to 243.1.83.254243.1.83.2551,022
86243.1.84.0/22243.1.84.1 to 243.1.87.254243.1.87.2551,022
87243.1.88.0/22243.1.88.1 to 243.1.91.254243.1.91.2551,022
88243.1.92.0/22243.1.92.1 to 243.1.95.254243.1.95.2551,022
89243.1.96.0/22243.1.96.1 to 243.1.99.254243.1.99.2551,022
90243.1.100.0/22243.1.100.1 to 243.1.103.254243.1.103.2551,022
91243.1.104.0/22243.1.104.1 to 243.1.107.254243.1.107.2551,022
92243.1.108.0/22243.1.108.1 to 243.1.111.254243.1.111.2551,022
93243.1.112.0/22243.1.112.1 to 243.1.115.254243.1.115.2551,022
94243.1.116.0/22243.1.116.1 to 243.1.119.254243.1.119.2551,022
95243.1.120.0/22243.1.120.1 to 243.1.123.254243.1.123.2551,022
96243.1.124.0/22243.1.124.1 to 243.1.127.254243.1.127.2551,022
97243.1.128.0/22243.1.128.1 to 243.1.131.254243.1.131.2551,022
98243.1.132.0/22243.1.132.1 to 243.1.135.254243.1.135.2551,022
99243.1.136.0/22243.1.136.1 to 243.1.139.254243.1.139.2551,022
100243.1.140.0/22243.1.140.1 to 243.1.143.254243.1.143.2551,022
101243.1.144.0/22243.1.144.1 to 243.1.147.254243.1.147.2551,022
102243.1.148.0/22243.1.148.1 to 243.1.151.254243.1.151.2551,022
103243.1.152.0/22243.1.152.1 to 243.1.155.254243.1.155.2551,022
104243.1.156.0/22243.1.156.1 to 243.1.159.254243.1.159.2551,022
105243.1.160.0/22243.1.160.1 to 243.1.163.254243.1.163.2551,022
106243.1.164.0/22243.1.164.1 to 243.1.167.254243.1.167.2551,022
107243.1.168.0/22243.1.168.1 to 243.1.171.254243.1.171.2551,022
108243.1.172.0/22243.1.172.1 to 243.1.175.254243.1.175.2551,022
109243.1.176.0/22243.1.176.1 to 243.1.179.254243.1.179.2551,022
110243.1.180.0/22243.1.180.1 to 243.1.183.254243.1.183.2551,022
111243.1.184.0/22243.1.184.1 to 243.1.187.254243.1.187.2551,022
112243.1.188.0/22243.1.188.1 to 243.1.191.254243.1.191.2551,022
113243.1.192.0/22243.1.192.1 to 243.1.195.254243.1.195.2551,022
114243.1.196.0/22243.1.196.1 to 243.1.199.254243.1.199.2551,022
115243.1.200.0/22243.1.200.1 to 243.1.203.254243.1.203.2551,022
116243.1.204.0/22243.1.204.1 to 243.1.207.254243.1.207.2551,022
117243.1.208.0/22243.1.208.1 to 243.1.211.254243.1.211.2551,022
118243.1.212.0/22243.1.212.1 to 243.1.215.254243.1.215.2551,022
119243.1.216.0/22243.1.216.1 to 243.1.219.254243.1.219.2551,022
120243.1.220.0/22243.1.220.1 to 243.1.223.254243.1.223.2551,022
121243.1.224.0/22243.1.224.1 to 243.1.227.254243.1.227.2551,022
122243.1.228.0/22243.1.228.1 to 243.1.231.254243.1.231.2551,022
123243.1.232.0/22243.1.232.1 to 243.1.235.254243.1.235.2551,022
124243.1.236.0/22243.1.236.1 to 243.1.239.254243.1.239.2551,022
125243.1.240.0/22243.1.240.1 to 243.1.243.254243.1.243.2551,022
126243.1.244.0/22243.1.244.1 to 243.1.247.254243.1.247.2551,022
127243.1.248.0/22243.1.248.1 to 243.1.251.254243.1.251.2551,022
128243.1.252.0/22243.1.252.1 to 243.1.255.254243.1.255.2551,022
129243.2.0.0/22243.2.0.1 to 243.2.3.254243.2.3.2551,022
130243.2.4.0/22243.2.4.1 to 243.2.7.254243.2.7.2551,022
131243.2.8.0/22243.2.8.1 to 243.2.11.254243.2.11.2551,022
132243.2.12.0/22243.2.12.1 to 243.2.15.254243.2.15.2551,022
133243.2.16.0/22243.2.16.1 to 243.2.19.254243.2.19.2551,022
134243.2.20.0/22243.2.20.1 to 243.2.23.254243.2.23.2551,022
135243.2.24.0/22243.2.24.1 to 243.2.27.254243.2.27.2551,022
136243.2.28.0/22243.2.28.1 to 243.2.31.254243.2.31.2551,022
137243.2.32.0/22243.2.32.1 to 243.2.35.254243.2.35.2551,022
138243.2.36.0/22243.2.36.1 to 243.2.39.254243.2.39.2551,022
139243.2.40.0/22243.2.40.1 to 243.2.43.254243.2.43.2551,022
140243.2.44.0/22243.2.44.1 to 243.2.47.254243.2.47.2551,022
141243.2.48.0/22243.2.48.1 to 243.2.51.254243.2.51.2551,022
142243.2.52.0/22243.2.52.1 to 243.2.55.254243.2.55.2551,022
143243.2.56.0/22243.2.56.1 to 243.2.59.254243.2.59.2551,022
144243.2.60.0/22243.2.60.1 to 243.2.63.254243.2.63.2551,022
145243.2.64.0/22243.2.64.1 to 243.2.67.254243.2.67.2551,022
146243.2.68.0/22243.2.68.1 to 243.2.71.254243.2.71.2551,022
147243.2.72.0/22243.2.72.1 to 243.2.75.254243.2.75.2551,022
148243.2.76.0/22243.2.76.1 to 243.2.79.254243.2.79.2551,022
149243.2.80.0/22243.2.80.1 to 243.2.83.254243.2.83.2551,022
150243.2.84.0/22243.2.84.1 to 243.2.87.254243.2.87.2551,022
151243.2.88.0/22243.2.88.1 to 243.2.91.254243.2.91.2551,022
152243.2.92.0/22243.2.92.1 to 243.2.95.254243.2.95.2551,022
153243.2.96.0/22243.2.96.1 to 243.2.99.254243.2.99.2551,022
154243.2.100.0/22243.2.100.1 to 243.2.103.254243.2.103.2551,022
155243.2.104.0/22243.2.104.1 to 243.2.107.254243.2.107.2551,022
156243.2.108.0/22243.2.108.1 to 243.2.111.254243.2.111.2551,022
157243.2.112.0/22243.2.112.1 to 243.2.115.254243.2.115.2551,022
158243.2.116.0/22243.2.116.1 to 243.2.119.254243.2.119.2551,022
159243.2.120.0/22243.2.120.1 to 243.2.123.254243.2.123.2551,022
160243.2.124.0/22243.2.124.1 to 243.2.127.254243.2.127.2551,022
161243.2.128.0/22243.2.128.1 to 243.2.131.254243.2.131.2551,022
162243.2.132.0/22243.2.132.1 to 243.2.135.254243.2.135.2551,022
163243.2.136.0/22243.2.136.1 to 243.2.139.254243.2.139.2551,022
164243.2.140.0/22243.2.140.1 to 243.2.143.254243.2.143.2551,022
165243.2.144.0/22243.2.144.1 to 243.2.147.254243.2.147.2551,022
166243.2.148.0/22243.2.148.1 to 243.2.151.254243.2.151.2551,022
167243.2.152.0/22243.2.152.1 to 243.2.155.254243.2.155.2551,022
168243.2.156.0/22243.2.156.1 to 243.2.159.254243.2.159.2551,022
169243.2.160.0/22243.2.160.1 to 243.2.163.254243.2.163.2551,022
170243.2.164.0/22243.2.164.1 to 243.2.167.254243.2.167.2551,022
171243.2.168.0/22243.2.168.1 to 243.2.171.254243.2.171.2551,022
172243.2.172.0/22243.2.172.1 to 243.2.175.254243.2.175.2551,022
173243.2.176.0/22243.2.176.1 to 243.2.179.254243.2.179.2551,022
174243.2.180.0/22243.2.180.1 to 243.2.183.254243.2.183.2551,022
175243.2.184.0/22243.2.184.1 to 243.2.187.254243.2.187.2551,022
176243.2.188.0/22243.2.188.1 to 243.2.191.254243.2.191.2551,022
177243.2.192.0/22243.2.192.1 to 243.2.195.254243.2.195.2551,022
178243.2.196.0/22243.2.196.1 to 243.2.199.254243.2.199.2551,022
179243.2.200.0/22243.2.200.1 to 243.2.203.254243.2.203.2551,022
180243.2.204.0/22243.2.204.1 to 243.2.207.254243.2.207.2551,022
181243.2.208.0/22243.2.208.1 to 243.2.211.254243.2.211.2551,022
182243.2.212.0/22243.2.212.1 to 243.2.215.254243.2.215.2551,022
183243.2.216.0/22243.2.216.1 to 243.2.219.254243.2.219.2551,022
184243.2.220.0/22243.2.220.1 to 243.2.223.254243.2.223.2551,022
185243.2.224.0/22243.2.224.1 to 243.2.227.254243.2.227.2551,022
186243.2.228.0/22243.2.228.1 to 243.2.231.254243.2.231.2551,022
187243.2.232.0/22243.2.232.1 to 243.2.235.254243.2.235.2551,022
188243.2.236.0/22243.2.236.1 to 243.2.239.254243.2.239.2551,022
189243.2.240.0/22243.2.240.1 to 243.2.243.254243.2.243.2551,022
190243.2.244.0/22243.2.244.1 to 243.2.247.254243.2.247.2551,022
191243.2.248.0/22243.2.248.1 to 243.2.251.254243.2.251.2551,022
192243.2.252.0/22243.2.252.1 to 243.2.255.254243.2.255.2551,022
193243.3.0.0/22243.3.0.1 to 243.3.3.254243.3.3.2551,022
194243.3.4.0/22243.3.4.1 to 243.3.7.254243.3.7.2551,022
195243.3.8.0/22243.3.8.1 to 243.3.11.254243.3.11.2551,022
196243.3.12.0/22243.3.12.1 to 243.3.15.254243.3.15.2551,022
197243.3.16.0/22243.3.16.1 to 243.3.19.254243.3.19.2551,022
198243.3.20.0/22243.3.20.1 to 243.3.23.254243.3.23.2551,022
199243.3.24.0/22243.3.24.1 to 243.3.27.254243.3.27.2551,022
200243.3.28.0/22243.3.28.1 to 243.3.31.254243.3.31.2551,022
201243.3.32.0/22243.3.32.1 to 243.3.35.254243.3.35.2551,022
202243.3.36.0/22243.3.36.1 to 243.3.39.254243.3.39.2551,022
203243.3.40.0/22243.3.40.1 to 243.3.43.254243.3.43.2551,022
204243.3.44.0/22243.3.44.1 to 243.3.47.254243.3.47.2551,022
205243.3.48.0/22243.3.48.1 to 243.3.51.254243.3.51.2551,022
206243.3.52.0/22243.3.52.1 to 243.3.55.254243.3.55.2551,022
207243.3.56.0/22243.3.56.1 to 243.3.59.254243.3.59.2551,022
208243.3.60.0/22243.3.60.1 to 243.3.63.254243.3.63.2551,022
209243.3.64.0/22243.3.64.1 to 243.3.67.254243.3.67.2551,022
210243.3.68.0/22243.3.68.1 to 243.3.71.254243.3.71.2551,022
211243.3.72.0/22243.3.72.1 to 243.3.75.254243.3.75.2551,022
212243.3.76.0/22243.3.76.1 to 243.3.79.254243.3.79.2551,022
213243.3.80.0/22243.3.80.1 to 243.3.83.254243.3.83.2551,022
214243.3.84.0/22243.3.84.1 to 243.3.87.254243.3.87.2551,022
215243.3.88.0/22243.3.88.1 to 243.3.91.254243.3.91.2551,022
216243.3.92.0/22243.3.92.1 to 243.3.95.254243.3.95.2551,022
217243.3.96.0/22243.3.96.1 to 243.3.99.254243.3.99.2551,022
218243.3.100.0/22243.3.100.1 to 243.3.103.254243.3.103.2551,022
219243.3.104.0/22243.3.104.1 to 243.3.107.254243.3.107.2551,022
220243.3.108.0/22243.3.108.1 to 243.3.111.254243.3.111.2551,022
221243.3.112.0/22243.3.112.1 to 243.3.115.254243.3.115.2551,022
222243.3.116.0/22243.3.116.1 to 243.3.119.254243.3.119.2551,022
223243.3.120.0/22243.3.120.1 to 243.3.123.254243.3.123.2551,022
224243.3.124.0/22243.3.124.1 to 243.3.127.254243.3.127.2551,022
225243.3.128.0/22243.3.128.1 to 243.3.131.254243.3.131.2551,022
226243.3.132.0/22243.3.132.1 to 243.3.135.254243.3.135.2551,022
227243.3.136.0/22243.3.136.1 to 243.3.139.254243.3.139.2551,022
228243.3.140.0/22243.3.140.1 to 243.3.143.254243.3.143.2551,022
229243.3.144.0/22243.3.144.1 to 243.3.147.254243.3.147.2551,022
230243.3.148.0/22243.3.148.1 to 243.3.151.254243.3.151.2551,022
231243.3.152.0/22243.3.152.1 to 243.3.155.254243.3.155.2551,022
232243.3.156.0/22243.3.156.1 to 243.3.159.254243.3.159.2551,022
233243.3.160.0/22243.3.160.1 to 243.3.163.254243.3.163.2551,022
234243.3.164.0/22243.3.164.1 to 243.3.167.254243.3.167.2551,022
235243.3.168.0/22243.3.168.1 to 243.3.171.254243.3.171.2551,022
236243.3.172.0/22243.3.172.1 to 243.3.175.254243.3.175.2551,022
237243.3.176.0/22243.3.176.1 to 243.3.179.254243.3.179.2551,022
238243.3.180.0/22243.3.180.1 to 243.3.183.254243.3.183.2551,022
239243.3.184.0/22243.3.184.1 to 243.3.187.254243.3.187.2551,022
240243.3.188.0/22243.3.188.1 to 243.3.191.254243.3.191.2551,022
241243.3.192.0/22243.3.192.1 to 243.3.195.254243.3.195.2551,022
242243.3.196.0/22243.3.196.1 to 243.3.199.254243.3.199.2551,022
243243.3.200.0/22243.3.200.1 to 243.3.203.254243.3.203.2551,022
244243.3.204.0/22243.3.204.1 to 243.3.207.254243.3.207.2551,022
245243.3.208.0/22243.3.208.1 to 243.3.211.254243.3.211.2551,022
246243.3.212.0/22243.3.212.1 to 243.3.215.254243.3.215.2551,022
247243.3.216.0/22243.3.216.1 to 243.3.219.254243.3.219.2551,022
248243.3.220.0/22243.3.220.1 to 243.3.223.254243.3.223.2551,022
249243.3.224.0/22243.3.224.1 to 243.3.227.254243.3.227.2551,022
250243.3.228.0/22243.3.228.1 to 243.3.231.254243.3.231.2551,022
251243.3.232.0/22243.3.232.1 to 243.3.235.254243.3.235.2551,022
252243.3.236.0/22243.3.236.1 to 243.3.239.254243.3.239.2551,022
253243.3.240.0/22243.3.240.1 to 243.3.243.254243.3.243.2551,022
254243.3.244.0/22243.3.244.1 to 243.3.247.254243.3.247.2551,022
255243.3.248.0/22243.3.248.1 to 243.3.251.254243.3.251.2551,022
256243.3.252.0/22243.3.252.1 to 243.3.255.254243.3.255.2551,022

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.