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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.

Network157.136.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
157.136.0.0
Broadcast address
157.143.255.255
First usable
157.136.0.1
Last usable
157.143.255.254
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
B (default /16)
As numbers
Hex 9D880000 · Integer 2642935808 to 2643460095
Reverse DNS zones
136.157.in-addr.arpa
137.157.in-addr.arpa
138.157.in-addr.arpa
139.157.in-addr.arpa
140.157.in-addr.arpa
141.157.in-addr.arpa
142.157.in-addr.arpa
143.157.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
Address10011101.10001000.00000000.00000000157.136.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network10011101.10001000.00000000.00000000157.136.0.0
Broadcast10011101.10001111.11111111.11111111157.143.255.255
Split into smaller subnets/21
/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)

157.136.0.0/13 makes 256 subnets of /21.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1157.136.0.0/21157.136.0.1 to 157.136.7.254157.136.7.2552,046
2157.136.8.0/21157.136.8.1 to 157.136.15.254157.136.15.2552,046
3157.136.16.0/21157.136.16.1 to 157.136.23.254157.136.23.2552,046
4157.136.24.0/21157.136.24.1 to 157.136.31.254157.136.31.2552,046
5157.136.32.0/21157.136.32.1 to 157.136.39.254157.136.39.2552,046
6157.136.40.0/21157.136.40.1 to 157.136.47.254157.136.47.2552,046
7157.136.48.0/21157.136.48.1 to 157.136.55.254157.136.55.2552,046
8157.136.56.0/21157.136.56.1 to 157.136.63.254157.136.63.2552,046
9157.136.64.0/21157.136.64.1 to 157.136.71.254157.136.71.2552,046
10157.136.72.0/21157.136.72.1 to 157.136.79.254157.136.79.2552,046
11157.136.80.0/21157.136.80.1 to 157.136.87.254157.136.87.2552,046
12157.136.88.0/21157.136.88.1 to 157.136.95.254157.136.95.2552,046
13157.136.96.0/21157.136.96.1 to 157.136.103.254157.136.103.2552,046
14157.136.104.0/21157.136.104.1 to 157.136.111.254157.136.111.2552,046
15157.136.112.0/21157.136.112.1 to 157.136.119.254157.136.119.2552,046
16157.136.120.0/21157.136.120.1 to 157.136.127.254157.136.127.2552,046
17157.136.128.0/21157.136.128.1 to 157.136.135.254157.136.135.2552,046
18157.136.136.0/21157.136.136.1 to 157.136.143.254157.136.143.2552,046
19157.136.144.0/21157.136.144.1 to 157.136.151.254157.136.151.2552,046
20157.136.152.0/21157.136.152.1 to 157.136.159.254157.136.159.2552,046
21157.136.160.0/21157.136.160.1 to 157.136.167.254157.136.167.2552,046
22157.136.168.0/21157.136.168.1 to 157.136.175.254157.136.175.2552,046
23157.136.176.0/21157.136.176.1 to 157.136.183.254157.136.183.2552,046
24157.136.184.0/21157.136.184.1 to 157.136.191.254157.136.191.2552,046
25157.136.192.0/21157.136.192.1 to 157.136.199.254157.136.199.2552,046
26157.136.200.0/21157.136.200.1 to 157.136.207.254157.136.207.2552,046
27157.136.208.0/21157.136.208.1 to 157.136.215.254157.136.215.2552,046
28157.136.216.0/21157.136.216.1 to 157.136.223.254157.136.223.2552,046
29157.136.224.0/21157.136.224.1 to 157.136.231.254157.136.231.2552,046
30157.136.232.0/21157.136.232.1 to 157.136.239.254157.136.239.2552,046
31157.136.240.0/21157.136.240.1 to 157.136.247.254157.136.247.2552,046
32157.136.248.0/21157.136.248.1 to 157.136.255.254157.136.255.2552,046
33157.137.0.0/21157.137.0.1 to 157.137.7.254157.137.7.2552,046
34157.137.8.0/21157.137.8.1 to 157.137.15.254157.137.15.2552,046
35157.137.16.0/21157.137.16.1 to 157.137.23.254157.137.23.2552,046
36157.137.24.0/21157.137.24.1 to 157.137.31.254157.137.31.2552,046
37157.137.32.0/21157.137.32.1 to 157.137.39.254157.137.39.2552,046
38157.137.40.0/21157.137.40.1 to 157.137.47.254157.137.47.2552,046
39157.137.48.0/21157.137.48.1 to 157.137.55.254157.137.55.2552,046
40157.137.56.0/21157.137.56.1 to 157.137.63.254157.137.63.2552,046
41157.137.64.0/21157.137.64.1 to 157.137.71.254157.137.71.2552,046
42157.137.72.0/21157.137.72.1 to 157.137.79.254157.137.79.2552,046
43157.137.80.0/21157.137.80.1 to 157.137.87.254157.137.87.2552,046
44157.137.88.0/21157.137.88.1 to 157.137.95.254157.137.95.2552,046
45157.137.96.0/21157.137.96.1 to 157.137.103.254157.137.103.2552,046
46157.137.104.0/21157.137.104.1 to 157.137.111.254157.137.111.2552,046
47157.137.112.0/21157.137.112.1 to 157.137.119.254157.137.119.2552,046
48157.137.120.0/21157.137.120.1 to 157.137.127.254157.137.127.2552,046
49157.137.128.0/21157.137.128.1 to 157.137.135.254157.137.135.2552,046
50157.137.136.0/21157.137.136.1 to 157.137.143.254157.137.143.2552,046
51157.137.144.0/21157.137.144.1 to 157.137.151.254157.137.151.2552,046
52157.137.152.0/21157.137.152.1 to 157.137.159.254157.137.159.2552,046
53157.137.160.0/21157.137.160.1 to 157.137.167.254157.137.167.2552,046
54157.137.168.0/21157.137.168.1 to 157.137.175.254157.137.175.2552,046
55157.137.176.0/21157.137.176.1 to 157.137.183.254157.137.183.2552,046
56157.137.184.0/21157.137.184.1 to 157.137.191.254157.137.191.2552,046
57157.137.192.0/21157.137.192.1 to 157.137.199.254157.137.199.2552,046
58157.137.200.0/21157.137.200.1 to 157.137.207.254157.137.207.2552,046
59157.137.208.0/21157.137.208.1 to 157.137.215.254157.137.215.2552,046
60157.137.216.0/21157.137.216.1 to 157.137.223.254157.137.223.2552,046
61157.137.224.0/21157.137.224.1 to 157.137.231.254157.137.231.2552,046
62157.137.232.0/21157.137.232.1 to 157.137.239.254157.137.239.2552,046
63157.137.240.0/21157.137.240.1 to 157.137.247.254157.137.247.2552,046
64157.137.248.0/21157.137.248.1 to 157.137.255.254157.137.255.2552,046
65157.138.0.0/21157.138.0.1 to 157.138.7.254157.138.7.2552,046
66157.138.8.0/21157.138.8.1 to 157.138.15.254157.138.15.2552,046
67157.138.16.0/21157.138.16.1 to 157.138.23.254157.138.23.2552,046
68157.138.24.0/21157.138.24.1 to 157.138.31.254157.138.31.2552,046
69157.138.32.0/21157.138.32.1 to 157.138.39.254157.138.39.2552,046
70157.138.40.0/21157.138.40.1 to 157.138.47.254157.138.47.2552,046
71157.138.48.0/21157.138.48.1 to 157.138.55.254157.138.55.2552,046
72157.138.56.0/21157.138.56.1 to 157.138.63.254157.138.63.2552,046
73157.138.64.0/21157.138.64.1 to 157.138.71.254157.138.71.2552,046
74157.138.72.0/21157.138.72.1 to 157.138.79.254157.138.79.2552,046
75157.138.80.0/21157.138.80.1 to 157.138.87.254157.138.87.2552,046
76157.138.88.0/21157.138.88.1 to 157.138.95.254157.138.95.2552,046
77157.138.96.0/21157.138.96.1 to 157.138.103.254157.138.103.2552,046
78157.138.104.0/21157.138.104.1 to 157.138.111.254157.138.111.2552,046
79157.138.112.0/21157.138.112.1 to 157.138.119.254157.138.119.2552,046
80157.138.120.0/21157.138.120.1 to 157.138.127.254157.138.127.2552,046
81157.138.128.0/21157.138.128.1 to 157.138.135.254157.138.135.2552,046
82157.138.136.0/21157.138.136.1 to 157.138.143.254157.138.143.2552,046
83157.138.144.0/21157.138.144.1 to 157.138.151.254157.138.151.2552,046
84157.138.152.0/21157.138.152.1 to 157.138.159.254157.138.159.2552,046
85157.138.160.0/21157.138.160.1 to 157.138.167.254157.138.167.2552,046
86157.138.168.0/21157.138.168.1 to 157.138.175.254157.138.175.2552,046
87157.138.176.0/21157.138.176.1 to 157.138.183.254157.138.183.2552,046
88157.138.184.0/21157.138.184.1 to 157.138.191.254157.138.191.2552,046
89157.138.192.0/21157.138.192.1 to 157.138.199.254157.138.199.2552,046
90157.138.200.0/21157.138.200.1 to 157.138.207.254157.138.207.2552,046
91157.138.208.0/21157.138.208.1 to 157.138.215.254157.138.215.2552,046
92157.138.216.0/21157.138.216.1 to 157.138.223.254157.138.223.2552,046
93157.138.224.0/21157.138.224.1 to 157.138.231.254157.138.231.2552,046
94157.138.232.0/21157.138.232.1 to 157.138.239.254157.138.239.2552,046
95157.138.240.0/21157.138.240.1 to 157.138.247.254157.138.247.2552,046
96157.138.248.0/21157.138.248.1 to 157.138.255.254157.138.255.2552,046
97157.139.0.0/21157.139.0.1 to 157.139.7.254157.139.7.2552,046
98157.139.8.0/21157.139.8.1 to 157.139.15.254157.139.15.2552,046
99157.139.16.0/21157.139.16.1 to 157.139.23.254157.139.23.2552,046
100157.139.24.0/21157.139.24.1 to 157.139.31.254157.139.31.2552,046
101157.139.32.0/21157.139.32.1 to 157.139.39.254157.139.39.2552,046
102157.139.40.0/21157.139.40.1 to 157.139.47.254157.139.47.2552,046
103157.139.48.0/21157.139.48.1 to 157.139.55.254157.139.55.2552,046
104157.139.56.0/21157.139.56.1 to 157.139.63.254157.139.63.2552,046
105157.139.64.0/21157.139.64.1 to 157.139.71.254157.139.71.2552,046
106157.139.72.0/21157.139.72.1 to 157.139.79.254157.139.79.2552,046
107157.139.80.0/21157.139.80.1 to 157.139.87.254157.139.87.2552,046
108157.139.88.0/21157.139.88.1 to 157.139.95.254157.139.95.2552,046
109157.139.96.0/21157.139.96.1 to 157.139.103.254157.139.103.2552,046
110157.139.104.0/21157.139.104.1 to 157.139.111.254157.139.111.2552,046
111157.139.112.0/21157.139.112.1 to 157.139.119.254157.139.119.2552,046
112157.139.120.0/21157.139.120.1 to 157.139.127.254157.139.127.2552,046
113157.139.128.0/21157.139.128.1 to 157.139.135.254157.139.135.2552,046
114157.139.136.0/21157.139.136.1 to 157.139.143.254157.139.143.2552,046
115157.139.144.0/21157.139.144.1 to 157.139.151.254157.139.151.2552,046
116157.139.152.0/21157.139.152.1 to 157.139.159.254157.139.159.2552,046
117157.139.160.0/21157.139.160.1 to 157.139.167.254157.139.167.2552,046
118157.139.168.0/21157.139.168.1 to 157.139.175.254157.139.175.2552,046
119157.139.176.0/21157.139.176.1 to 157.139.183.254157.139.183.2552,046
120157.139.184.0/21157.139.184.1 to 157.139.191.254157.139.191.2552,046
121157.139.192.0/21157.139.192.1 to 157.139.199.254157.139.199.2552,046
122157.139.200.0/21157.139.200.1 to 157.139.207.254157.139.207.2552,046
123157.139.208.0/21157.139.208.1 to 157.139.215.254157.139.215.2552,046
124157.139.216.0/21157.139.216.1 to 157.139.223.254157.139.223.2552,046
125157.139.224.0/21157.139.224.1 to 157.139.231.254157.139.231.2552,046
126157.139.232.0/21157.139.232.1 to 157.139.239.254157.139.239.2552,046
127157.139.240.0/21157.139.240.1 to 157.139.247.254157.139.247.2552,046
128157.139.248.0/21157.139.248.1 to 157.139.255.254157.139.255.2552,046
129157.140.0.0/21157.140.0.1 to 157.140.7.254157.140.7.2552,046
130157.140.8.0/21157.140.8.1 to 157.140.15.254157.140.15.2552,046
131157.140.16.0/21157.140.16.1 to 157.140.23.254157.140.23.2552,046
132157.140.24.0/21157.140.24.1 to 157.140.31.254157.140.31.2552,046
133157.140.32.0/21157.140.32.1 to 157.140.39.254157.140.39.2552,046
134157.140.40.0/21157.140.40.1 to 157.140.47.254157.140.47.2552,046
135157.140.48.0/21157.140.48.1 to 157.140.55.254157.140.55.2552,046
136157.140.56.0/21157.140.56.1 to 157.140.63.254157.140.63.2552,046
137157.140.64.0/21157.140.64.1 to 157.140.71.254157.140.71.2552,046
138157.140.72.0/21157.140.72.1 to 157.140.79.254157.140.79.2552,046
139157.140.80.0/21157.140.80.1 to 157.140.87.254157.140.87.2552,046
140157.140.88.0/21157.140.88.1 to 157.140.95.254157.140.95.2552,046
141157.140.96.0/21157.140.96.1 to 157.140.103.254157.140.103.2552,046
142157.140.104.0/21157.140.104.1 to 157.140.111.254157.140.111.2552,046
143157.140.112.0/21157.140.112.1 to 157.140.119.254157.140.119.2552,046
144157.140.120.0/21157.140.120.1 to 157.140.127.254157.140.127.2552,046
145157.140.128.0/21157.140.128.1 to 157.140.135.254157.140.135.2552,046
146157.140.136.0/21157.140.136.1 to 157.140.143.254157.140.143.2552,046
147157.140.144.0/21157.140.144.1 to 157.140.151.254157.140.151.2552,046
148157.140.152.0/21157.140.152.1 to 157.140.159.254157.140.159.2552,046
149157.140.160.0/21157.140.160.1 to 157.140.167.254157.140.167.2552,046
150157.140.168.0/21157.140.168.1 to 157.140.175.254157.140.175.2552,046
151157.140.176.0/21157.140.176.1 to 157.140.183.254157.140.183.2552,046
152157.140.184.0/21157.140.184.1 to 157.140.191.254157.140.191.2552,046
153157.140.192.0/21157.140.192.1 to 157.140.199.254157.140.199.2552,046
154157.140.200.0/21157.140.200.1 to 157.140.207.254157.140.207.2552,046
155157.140.208.0/21157.140.208.1 to 157.140.215.254157.140.215.2552,046
156157.140.216.0/21157.140.216.1 to 157.140.223.254157.140.223.2552,046
157157.140.224.0/21157.140.224.1 to 157.140.231.254157.140.231.2552,046
158157.140.232.0/21157.140.232.1 to 157.140.239.254157.140.239.2552,046
159157.140.240.0/21157.140.240.1 to 157.140.247.254157.140.247.2552,046
160157.140.248.0/21157.140.248.1 to 157.140.255.254157.140.255.2552,046
161157.141.0.0/21157.141.0.1 to 157.141.7.254157.141.7.2552,046
162157.141.8.0/21157.141.8.1 to 157.141.15.254157.141.15.2552,046
163157.141.16.0/21157.141.16.1 to 157.141.23.254157.141.23.2552,046
164157.141.24.0/21157.141.24.1 to 157.141.31.254157.141.31.2552,046
165157.141.32.0/21157.141.32.1 to 157.141.39.254157.141.39.2552,046
166157.141.40.0/21157.141.40.1 to 157.141.47.254157.141.47.2552,046
167157.141.48.0/21157.141.48.1 to 157.141.55.254157.141.55.2552,046
168157.141.56.0/21157.141.56.1 to 157.141.63.254157.141.63.2552,046
169157.141.64.0/21157.141.64.1 to 157.141.71.254157.141.71.2552,046
170157.141.72.0/21157.141.72.1 to 157.141.79.254157.141.79.2552,046
171157.141.80.0/21157.141.80.1 to 157.141.87.254157.141.87.2552,046
172157.141.88.0/21157.141.88.1 to 157.141.95.254157.141.95.2552,046
173157.141.96.0/21157.141.96.1 to 157.141.103.254157.141.103.2552,046
174157.141.104.0/21157.141.104.1 to 157.141.111.254157.141.111.2552,046
175157.141.112.0/21157.141.112.1 to 157.141.119.254157.141.119.2552,046
176157.141.120.0/21157.141.120.1 to 157.141.127.254157.141.127.2552,046
177157.141.128.0/21157.141.128.1 to 157.141.135.254157.141.135.2552,046
178157.141.136.0/21157.141.136.1 to 157.141.143.254157.141.143.2552,046
179157.141.144.0/21157.141.144.1 to 157.141.151.254157.141.151.2552,046
180157.141.152.0/21157.141.152.1 to 157.141.159.254157.141.159.2552,046
181157.141.160.0/21157.141.160.1 to 157.141.167.254157.141.167.2552,046
182157.141.168.0/21157.141.168.1 to 157.141.175.254157.141.175.2552,046
183157.141.176.0/21157.141.176.1 to 157.141.183.254157.141.183.2552,046
184157.141.184.0/21157.141.184.1 to 157.141.191.254157.141.191.2552,046
185157.141.192.0/21157.141.192.1 to 157.141.199.254157.141.199.2552,046
186157.141.200.0/21157.141.200.1 to 157.141.207.254157.141.207.2552,046
187157.141.208.0/21157.141.208.1 to 157.141.215.254157.141.215.2552,046
188157.141.216.0/21157.141.216.1 to 157.141.223.254157.141.223.2552,046
189157.141.224.0/21157.141.224.1 to 157.141.231.254157.141.231.2552,046
190157.141.232.0/21157.141.232.1 to 157.141.239.254157.141.239.2552,046
191157.141.240.0/21157.141.240.1 to 157.141.247.254157.141.247.2552,046
192157.141.248.0/21157.141.248.1 to 157.141.255.254157.141.255.2552,046
193157.142.0.0/21157.142.0.1 to 157.142.7.254157.142.7.2552,046
194157.142.8.0/21157.142.8.1 to 157.142.15.254157.142.15.2552,046
195157.142.16.0/21157.142.16.1 to 157.142.23.254157.142.23.2552,046
196157.142.24.0/21157.142.24.1 to 157.142.31.254157.142.31.2552,046
197157.142.32.0/21157.142.32.1 to 157.142.39.254157.142.39.2552,046
198157.142.40.0/21157.142.40.1 to 157.142.47.254157.142.47.2552,046
199157.142.48.0/21157.142.48.1 to 157.142.55.254157.142.55.2552,046
200157.142.56.0/21157.142.56.1 to 157.142.63.254157.142.63.2552,046
201157.142.64.0/21157.142.64.1 to 157.142.71.254157.142.71.2552,046
202157.142.72.0/21157.142.72.1 to 157.142.79.254157.142.79.2552,046
203157.142.80.0/21157.142.80.1 to 157.142.87.254157.142.87.2552,046
204157.142.88.0/21157.142.88.1 to 157.142.95.254157.142.95.2552,046
205157.142.96.0/21157.142.96.1 to 157.142.103.254157.142.103.2552,046
206157.142.104.0/21157.142.104.1 to 157.142.111.254157.142.111.2552,046
207157.142.112.0/21157.142.112.1 to 157.142.119.254157.142.119.2552,046
208157.142.120.0/21157.142.120.1 to 157.142.127.254157.142.127.2552,046
209157.142.128.0/21157.142.128.1 to 157.142.135.254157.142.135.2552,046
210157.142.136.0/21157.142.136.1 to 157.142.143.254157.142.143.2552,046
211157.142.144.0/21157.142.144.1 to 157.142.151.254157.142.151.2552,046
212157.142.152.0/21157.142.152.1 to 157.142.159.254157.142.159.2552,046
213157.142.160.0/21157.142.160.1 to 157.142.167.254157.142.167.2552,046
214157.142.168.0/21157.142.168.1 to 157.142.175.254157.142.175.2552,046
215157.142.176.0/21157.142.176.1 to 157.142.183.254157.142.183.2552,046
216157.142.184.0/21157.142.184.1 to 157.142.191.254157.142.191.2552,046
217157.142.192.0/21157.142.192.1 to 157.142.199.254157.142.199.2552,046
218157.142.200.0/21157.142.200.1 to 157.142.207.254157.142.207.2552,046
219157.142.208.0/21157.142.208.1 to 157.142.215.254157.142.215.2552,046
220157.142.216.0/21157.142.216.1 to 157.142.223.254157.142.223.2552,046
221157.142.224.0/21157.142.224.1 to 157.142.231.254157.142.231.2552,046
222157.142.232.0/21157.142.232.1 to 157.142.239.254157.142.239.2552,046
223157.142.240.0/21157.142.240.1 to 157.142.247.254157.142.247.2552,046
224157.142.248.0/21157.142.248.1 to 157.142.255.254157.142.255.2552,046
225157.143.0.0/21157.143.0.1 to 157.143.7.254157.143.7.2552,046
226157.143.8.0/21157.143.8.1 to 157.143.15.254157.143.15.2552,046
227157.143.16.0/21157.143.16.1 to 157.143.23.254157.143.23.2552,046
228157.143.24.0/21157.143.24.1 to 157.143.31.254157.143.31.2552,046
229157.143.32.0/21157.143.32.1 to 157.143.39.254157.143.39.2552,046
230157.143.40.0/21157.143.40.1 to 157.143.47.254157.143.47.2552,046
231157.143.48.0/21157.143.48.1 to 157.143.55.254157.143.55.2552,046
232157.143.56.0/21157.143.56.1 to 157.143.63.254157.143.63.2552,046
233157.143.64.0/21157.143.64.1 to 157.143.71.254157.143.71.2552,046
234157.143.72.0/21157.143.72.1 to 157.143.79.254157.143.79.2552,046
235157.143.80.0/21157.143.80.1 to 157.143.87.254157.143.87.2552,046
236157.143.88.0/21157.143.88.1 to 157.143.95.254157.143.95.2552,046
237157.143.96.0/21157.143.96.1 to 157.143.103.254157.143.103.2552,046
238157.143.104.0/21157.143.104.1 to 157.143.111.254157.143.111.2552,046
239157.143.112.0/21157.143.112.1 to 157.143.119.254157.143.119.2552,046
240157.143.120.0/21157.143.120.1 to 157.143.127.254157.143.127.2552,046
241157.143.128.0/21157.143.128.1 to 157.143.135.254157.143.135.2552,046
242157.143.136.0/21157.143.136.1 to 157.143.143.254157.143.143.2552,046
243157.143.144.0/21157.143.144.1 to 157.143.151.254157.143.151.2552,046
244157.143.152.0/21157.143.152.1 to 157.143.159.254157.143.159.2552,046
245157.143.160.0/21157.143.160.1 to 157.143.167.254157.143.167.2552,046
246157.143.168.0/21157.143.168.1 to 157.143.175.254157.143.175.2552,046
247157.143.176.0/21157.143.176.1 to 157.143.183.254157.143.183.2552,046
248157.143.184.0/21157.143.184.1 to 157.143.191.254157.143.191.2552,046
249157.143.192.0/21157.143.192.1 to 157.143.199.254157.143.199.2552,046
250157.143.200.0/21157.143.200.1 to 157.143.207.254157.143.207.2552,046
251157.143.208.0/21157.143.208.1 to 157.143.215.254157.143.215.2552,046
252157.143.216.0/21157.143.216.1 to 157.143.223.254157.143.223.2552,046
253157.143.224.0/21157.143.224.1 to 157.143.231.254157.143.231.2552,046
254157.143.232.0/21157.143.232.1 to 157.143.239.254157.143.239.2552,046
255157.143.240.0/21157.143.240.1 to 157.143.247.254157.143.247.2552,046
256157.143.248.0/21157.143.248.1 to 157.143.255.254157.143.255.2552,046

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.