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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.

Network173.0.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
173.0.0.0
Broadcast address
173.63.255.255
First usable
173.0.0.1
Last usable
173.63.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Public public
Old class
B (default /16)
As numbers
Hex AD000000 · Integer 2902458368 to 2906652671
Reverse DNS zones
0.173.in-addr.arpa
1.173.in-addr.arpa
2.173.in-addr.arpa
3.173.in-addr.arpa
4.173.in-addr.arpa
5.173.in-addr.arpa
6.173.in-addr.arpa
7.173.in-addr.arpa
8.173.in-addr.arpa
9.173.in-addr.arpa
10.173.in-addr.arpa
11.173.in-addr.arpa
12.173.in-addr.arpa
13.173.in-addr.arpa
14.173.in-addr.arpa
15.173.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10101101.00000000.00000000.00000000173.0.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network10101101.00000000.00000000.00000000173.0.0.0
Broadcast10101101.00111111.11111111.11111111173.63.255.255
Split into smaller subnets/21
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

173.0.0.0/10 makes 2,048 subnets of /21; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1173.0.0.0/21173.0.0.1 to 173.0.7.254173.0.7.2552,046
2173.0.8.0/21173.0.8.1 to 173.0.15.254173.0.15.2552,046
3173.0.16.0/21173.0.16.1 to 173.0.23.254173.0.23.2552,046
4173.0.24.0/21173.0.24.1 to 173.0.31.254173.0.31.2552,046
5173.0.32.0/21173.0.32.1 to 173.0.39.254173.0.39.2552,046
6173.0.40.0/21173.0.40.1 to 173.0.47.254173.0.47.2552,046
7173.0.48.0/21173.0.48.1 to 173.0.55.254173.0.55.2552,046
8173.0.56.0/21173.0.56.1 to 173.0.63.254173.0.63.2552,046
9173.0.64.0/21173.0.64.1 to 173.0.71.254173.0.71.2552,046
10173.0.72.0/21173.0.72.1 to 173.0.79.254173.0.79.2552,046
11173.0.80.0/21173.0.80.1 to 173.0.87.254173.0.87.2552,046
12173.0.88.0/21173.0.88.1 to 173.0.95.254173.0.95.2552,046
13173.0.96.0/21173.0.96.1 to 173.0.103.254173.0.103.2552,046
14173.0.104.0/21173.0.104.1 to 173.0.111.254173.0.111.2552,046
15173.0.112.0/21173.0.112.1 to 173.0.119.254173.0.119.2552,046
16173.0.120.0/21173.0.120.1 to 173.0.127.254173.0.127.2552,046
17173.0.128.0/21173.0.128.1 to 173.0.135.254173.0.135.2552,046
18173.0.136.0/21173.0.136.1 to 173.0.143.254173.0.143.2552,046
19173.0.144.0/21173.0.144.1 to 173.0.151.254173.0.151.2552,046
20173.0.152.0/21173.0.152.1 to 173.0.159.254173.0.159.2552,046
21173.0.160.0/21173.0.160.1 to 173.0.167.254173.0.167.2552,046
22173.0.168.0/21173.0.168.1 to 173.0.175.254173.0.175.2552,046
23173.0.176.0/21173.0.176.1 to 173.0.183.254173.0.183.2552,046
24173.0.184.0/21173.0.184.1 to 173.0.191.254173.0.191.2552,046
25173.0.192.0/21173.0.192.1 to 173.0.199.254173.0.199.2552,046
26173.0.200.0/21173.0.200.1 to 173.0.207.254173.0.207.2552,046
27173.0.208.0/21173.0.208.1 to 173.0.215.254173.0.215.2552,046
28173.0.216.0/21173.0.216.1 to 173.0.223.254173.0.223.2552,046
29173.0.224.0/21173.0.224.1 to 173.0.231.254173.0.231.2552,046
30173.0.232.0/21173.0.232.1 to 173.0.239.254173.0.239.2552,046
31173.0.240.0/21173.0.240.1 to 173.0.247.254173.0.247.2552,046
32173.0.248.0/21173.0.248.1 to 173.0.255.254173.0.255.2552,046
33173.1.0.0/21173.1.0.1 to 173.1.7.254173.1.7.2552,046
34173.1.8.0/21173.1.8.1 to 173.1.15.254173.1.15.2552,046
35173.1.16.0/21173.1.16.1 to 173.1.23.254173.1.23.2552,046
36173.1.24.0/21173.1.24.1 to 173.1.31.254173.1.31.2552,046
37173.1.32.0/21173.1.32.1 to 173.1.39.254173.1.39.2552,046
38173.1.40.0/21173.1.40.1 to 173.1.47.254173.1.47.2552,046
39173.1.48.0/21173.1.48.1 to 173.1.55.254173.1.55.2552,046
40173.1.56.0/21173.1.56.1 to 173.1.63.254173.1.63.2552,046
41173.1.64.0/21173.1.64.1 to 173.1.71.254173.1.71.2552,046
42173.1.72.0/21173.1.72.1 to 173.1.79.254173.1.79.2552,046
43173.1.80.0/21173.1.80.1 to 173.1.87.254173.1.87.2552,046
44173.1.88.0/21173.1.88.1 to 173.1.95.254173.1.95.2552,046
45173.1.96.0/21173.1.96.1 to 173.1.103.254173.1.103.2552,046
46173.1.104.0/21173.1.104.1 to 173.1.111.254173.1.111.2552,046
47173.1.112.0/21173.1.112.1 to 173.1.119.254173.1.119.2552,046
48173.1.120.0/21173.1.120.1 to 173.1.127.254173.1.127.2552,046
49173.1.128.0/21173.1.128.1 to 173.1.135.254173.1.135.2552,046
50173.1.136.0/21173.1.136.1 to 173.1.143.254173.1.143.2552,046
51173.1.144.0/21173.1.144.1 to 173.1.151.254173.1.151.2552,046
52173.1.152.0/21173.1.152.1 to 173.1.159.254173.1.159.2552,046
53173.1.160.0/21173.1.160.1 to 173.1.167.254173.1.167.2552,046
54173.1.168.0/21173.1.168.1 to 173.1.175.254173.1.175.2552,046
55173.1.176.0/21173.1.176.1 to 173.1.183.254173.1.183.2552,046
56173.1.184.0/21173.1.184.1 to 173.1.191.254173.1.191.2552,046
57173.1.192.0/21173.1.192.1 to 173.1.199.254173.1.199.2552,046
58173.1.200.0/21173.1.200.1 to 173.1.207.254173.1.207.2552,046
59173.1.208.0/21173.1.208.1 to 173.1.215.254173.1.215.2552,046
60173.1.216.0/21173.1.216.1 to 173.1.223.254173.1.223.2552,046
61173.1.224.0/21173.1.224.1 to 173.1.231.254173.1.231.2552,046
62173.1.232.0/21173.1.232.1 to 173.1.239.254173.1.239.2552,046
63173.1.240.0/21173.1.240.1 to 173.1.247.254173.1.247.2552,046
64173.1.248.0/21173.1.248.1 to 173.1.255.254173.1.255.2552,046
65173.2.0.0/21173.2.0.1 to 173.2.7.254173.2.7.2552,046
66173.2.8.0/21173.2.8.1 to 173.2.15.254173.2.15.2552,046
67173.2.16.0/21173.2.16.1 to 173.2.23.254173.2.23.2552,046
68173.2.24.0/21173.2.24.1 to 173.2.31.254173.2.31.2552,046
69173.2.32.0/21173.2.32.1 to 173.2.39.254173.2.39.2552,046
70173.2.40.0/21173.2.40.1 to 173.2.47.254173.2.47.2552,046
71173.2.48.0/21173.2.48.1 to 173.2.55.254173.2.55.2552,046
72173.2.56.0/21173.2.56.1 to 173.2.63.254173.2.63.2552,046
73173.2.64.0/21173.2.64.1 to 173.2.71.254173.2.71.2552,046
74173.2.72.0/21173.2.72.1 to 173.2.79.254173.2.79.2552,046
75173.2.80.0/21173.2.80.1 to 173.2.87.254173.2.87.2552,046
76173.2.88.0/21173.2.88.1 to 173.2.95.254173.2.95.2552,046
77173.2.96.0/21173.2.96.1 to 173.2.103.254173.2.103.2552,046
78173.2.104.0/21173.2.104.1 to 173.2.111.254173.2.111.2552,046
79173.2.112.0/21173.2.112.1 to 173.2.119.254173.2.119.2552,046
80173.2.120.0/21173.2.120.1 to 173.2.127.254173.2.127.2552,046
81173.2.128.0/21173.2.128.1 to 173.2.135.254173.2.135.2552,046
82173.2.136.0/21173.2.136.1 to 173.2.143.254173.2.143.2552,046
83173.2.144.0/21173.2.144.1 to 173.2.151.254173.2.151.2552,046
84173.2.152.0/21173.2.152.1 to 173.2.159.254173.2.159.2552,046
85173.2.160.0/21173.2.160.1 to 173.2.167.254173.2.167.2552,046
86173.2.168.0/21173.2.168.1 to 173.2.175.254173.2.175.2552,046
87173.2.176.0/21173.2.176.1 to 173.2.183.254173.2.183.2552,046
88173.2.184.0/21173.2.184.1 to 173.2.191.254173.2.191.2552,046
89173.2.192.0/21173.2.192.1 to 173.2.199.254173.2.199.2552,046
90173.2.200.0/21173.2.200.1 to 173.2.207.254173.2.207.2552,046
91173.2.208.0/21173.2.208.1 to 173.2.215.254173.2.215.2552,046
92173.2.216.0/21173.2.216.1 to 173.2.223.254173.2.223.2552,046
93173.2.224.0/21173.2.224.1 to 173.2.231.254173.2.231.2552,046
94173.2.232.0/21173.2.232.1 to 173.2.239.254173.2.239.2552,046
95173.2.240.0/21173.2.240.1 to 173.2.247.254173.2.247.2552,046
96173.2.248.0/21173.2.248.1 to 173.2.255.254173.2.255.2552,046
97173.3.0.0/21173.3.0.1 to 173.3.7.254173.3.7.2552,046
98173.3.8.0/21173.3.8.1 to 173.3.15.254173.3.15.2552,046
99173.3.16.0/21173.3.16.1 to 173.3.23.254173.3.23.2552,046
100173.3.24.0/21173.3.24.1 to 173.3.31.254173.3.31.2552,046
101173.3.32.0/21173.3.32.1 to 173.3.39.254173.3.39.2552,046
102173.3.40.0/21173.3.40.1 to 173.3.47.254173.3.47.2552,046
103173.3.48.0/21173.3.48.1 to 173.3.55.254173.3.55.2552,046
104173.3.56.0/21173.3.56.1 to 173.3.63.254173.3.63.2552,046
105173.3.64.0/21173.3.64.1 to 173.3.71.254173.3.71.2552,046
106173.3.72.0/21173.3.72.1 to 173.3.79.254173.3.79.2552,046
107173.3.80.0/21173.3.80.1 to 173.3.87.254173.3.87.2552,046
108173.3.88.0/21173.3.88.1 to 173.3.95.254173.3.95.2552,046
109173.3.96.0/21173.3.96.1 to 173.3.103.254173.3.103.2552,046
110173.3.104.0/21173.3.104.1 to 173.3.111.254173.3.111.2552,046
111173.3.112.0/21173.3.112.1 to 173.3.119.254173.3.119.2552,046
112173.3.120.0/21173.3.120.1 to 173.3.127.254173.3.127.2552,046
113173.3.128.0/21173.3.128.1 to 173.3.135.254173.3.135.2552,046
114173.3.136.0/21173.3.136.1 to 173.3.143.254173.3.143.2552,046
115173.3.144.0/21173.3.144.1 to 173.3.151.254173.3.151.2552,046
116173.3.152.0/21173.3.152.1 to 173.3.159.254173.3.159.2552,046
117173.3.160.0/21173.3.160.1 to 173.3.167.254173.3.167.2552,046
118173.3.168.0/21173.3.168.1 to 173.3.175.254173.3.175.2552,046
119173.3.176.0/21173.3.176.1 to 173.3.183.254173.3.183.2552,046
120173.3.184.0/21173.3.184.1 to 173.3.191.254173.3.191.2552,046
121173.3.192.0/21173.3.192.1 to 173.3.199.254173.3.199.2552,046
122173.3.200.0/21173.3.200.1 to 173.3.207.254173.3.207.2552,046
123173.3.208.0/21173.3.208.1 to 173.3.215.254173.3.215.2552,046
124173.3.216.0/21173.3.216.1 to 173.3.223.254173.3.223.2552,046
125173.3.224.0/21173.3.224.1 to 173.3.231.254173.3.231.2552,046
126173.3.232.0/21173.3.232.1 to 173.3.239.254173.3.239.2552,046
127173.3.240.0/21173.3.240.1 to 173.3.247.254173.3.247.2552,046
128173.3.248.0/21173.3.248.1 to 173.3.255.254173.3.255.2552,046
129173.4.0.0/21173.4.0.1 to 173.4.7.254173.4.7.2552,046
130173.4.8.0/21173.4.8.1 to 173.4.15.254173.4.15.2552,046
131173.4.16.0/21173.4.16.1 to 173.4.23.254173.4.23.2552,046
132173.4.24.0/21173.4.24.1 to 173.4.31.254173.4.31.2552,046
133173.4.32.0/21173.4.32.1 to 173.4.39.254173.4.39.2552,046
134173.4.40.0/21173.4.40.1 to 173.4.47.254173.4.47.2552,046
135173.4.48.0/21173.4.48.1 to 173.4.55.254173.4.55.2552,046
136173.4.56.0/21173.4.56.1 to 173.4.63.254173.4.63.2552,046
137173.4.64.0/21173.4.64.1 to 173.4.71.254173.4.71.2552,046
138173.4.72.0/21173.4.72.1 to 173.4.79.254173.4.79.2552,046
139173.4.80.0/21173.4.80.1 to 173.4.87.254173.4.87.2552,046
140173.4.88.0/21173.4.88.1 to 173.4.95.254173.4.95.2552,046
141173.4.96.0/21173.4.96.1 to 173.4.103.254173.4.103.2552,046
142173.4.104.0/21173.4.104.1 to 173.4.111.254173.4.111.2552,046
143173.4.112.0/21173.4.112.1 to 173.4.119.254173.4.119.2552,046
144173.4.120.0/21173.4.120.1 to 173.4.127.254173.4.127.2552,046
145173.4.128.0/21173.4.128.1 to 173.4.135.254173.4.135.2552,046
146173.4.136.0/21173.4.136.1 to 173.4.143.254173.4.143.2552,046
147173.4.144.0/21173.4.144.1 to 173.4.151.254173.4.151.2552,046
148173.4.152.0/21173.4.152.1 to 173.4.159.254173.4.159.2552,046
149173.4.160.0/21173.4.160.1 to 173.4.167.254173.4.167.2552,046
150173.4.168.0/21173.4.168.1 to 173.4.175.254173.4.175.2552,046
151173.4.176.0/21173.4.176.1 to 173.4.183.254173.4.183.2552,046
152173.4.184.0/21173.4.184.1 to 173.4.191.254173.4.191.2552,046
153173.4.192.0/21173.4.192.1 to 173.4.199.254173.4.199.2552,046
154173.4.200.0/21173.4.200.1 to 173.4.207.254173.4.207.2552,046
155173.4.208.0/21173.4.208.1 to 173.4.215.254173.4.215.2552,046
156173.4.216.0/21173.4.216.1 to 173.4.223.254173.4.223.2552,046
157173.4.224.0/21173.4.224.1 to 173.4.231.254173.4.231.2552,046
158173.4.232.0/21173.4.232.1 to 173.4.239.254173.4.239.2552,046
159173.4.240.0/21173.4.240.1 to 173.4.247.254173.4.247.2552,046
160173.4.248.0/21173.4.248.1 to 173.4.255.254173.4.255.2552,046
161173.5.0.0/21173.5.0.1 to 173.5.7.254173.5.7.2552,046
162173.5.8.0/21173.5.8.1 to 173.5.15.254173.5.15.2552,046
163173.5.16.0/21173.5.16.1 to 173.5.23.254173.5.23.2552,046
164173.5.24.0/21173.5.24.1 to 173.5.31.254173.5.31.2552,046
165173.5.32.0/21173.5.32.1 to 173.5.39.254173.5.39.2552,046
166173.5.40.0/21173.5.40.1 to 173.5.47.254173.5.47.2552,046
167173.5.48.0/21173.5.48.1 to 173.5.55.254173.5.55.2552,046
168173.5.56.0/21173.5.56.1 to 173.5.63.254173.5.63.2552,046
169173.5.64.0/21173.5.64.1 to 173.5.71.254173.5.71.2552,046
170173.5.72.0/21173.5.72.1 to 173.5.79.254173.5.79.2552,046
171173.5.80.0/21173.5.80.1 to 173.5.87.254173.5.87.2552,046
172173.5.88.0/21173.5.88.1 to 173.5.95.254173.5.95.2552,046
173173.5.96.0/21173.5.96.1 to 173.5.103.254173.5.103.2552,046
174173.5.104.0/21173.5.104.1 to 173.5.111.254173.5.111.2552,046
175173.5.112.0/21173.5.112.1 to 173.5.119.254173.5.119.2552,046
176173.5.120.0/21173.5.120.1 to 173.5.127.254173.5.127.2552,046
177173.5.128.0/21173.5.128.1 to 173.5.135.254173.5.135.2552,046
178173.5.136.0/21173.5.136.1 to 173.5.143.254173.5.143.2552,046
179173.5.144.0/21173.5.144.1 to 173.5.151.254173.5.151.2552,046
180173.5.152.0/21173.5.152.1 to 173.5.159.254173.5.159.2552,046
181173.5.160.0/21173.5.160.1 to 173.5.167.254173.5.167.2552,046
182173.5.168.0/21173.5.168.1 to 173.5.175.254173.5.175.2552,046
183173.5.176.0/21173.5.176.1 to 173.5.183.254173.5.183.2552,046
184173.5.184.0/21173.5.184.1 to 173.5.191.254173.5.191.2552,046
185173.5.192.0/21173.5.192.1 to 173.5.199.254173.5.199.2552,046
186173.5.200.0/21173.5.200.1 to 173.5.207.254173.5.207.2552,046
187173.5.208.0/21173.5.208.1 to 173.5.215.254173.5.215.2552,046
188173.5.216.0/21173.5.216.1 to 173.5.223.254173.5.223.2552,046
189173.5.224.0/21173.5.224.1 to 173.5.231.254173.5.231.2552,046
190173.5.232.0/21173.5.232.1 to 173.5.239.254173.5.239.2552,046
191173.5.240.0/21173.5.240.1 to 173.5.247.254173.5.247.2552,046
192173.5.248.0/21173.5.248.1 to 173.5.255.254173.5.255.2552,046
193173.6.0.0/21173.6.0.1 to 173.6.7.254173.6.7.2552,046
194173.6.8.0/21173.6.8.1 to 173.6.15.254173.6.15.2552,046
195173.6.16.0/21173.6.16.1 to 173.6.23.254173.6.23.2552,046
196173.6.24.0/21173.6.24.1 to 173.6.31.254173.6.31.2552,046
197173.6.32.0/21173.6.32.1 to 173.6.39.254173.6.39.2552,046
198173.6.40.0/21173.6.40.1 to 173.6.47.254173.6.47.2552,046
199173.6.48.0/21173.6.48.1 to 173.6.55.254173.6.55.2552,046
200173.6.56.0/21173.6.56.1 to 173.6.63.254173.6.63.2552,046
201173.6.64.0/21173.6.64.1 to 173.6.71.254173.6.71.2552,046
202173.6.72.0/21173.6.72.1 to 173.6.79.254173.6.79.2552,046
203173.6.80.0/21173.6.80.1 to 173.6.87.254173.6.87.2552,046
204173.6.88.0/21173.6.88.1 to 173.6.95.254173.6.95.2552,046
205173.6.96.0/21173.6.96.1 to 173.6.103.254173.6.103.2552,046
206173.6.104.0/21173.6.104.1 to 173.6.111.254173.6.111.2552,046
207173.6.112.0/21173.6.112.1 to 173.6.119.254173.6.119.2552,046
208173.6.120.0/21173.6.120.1 to 173.6.127.254173.6.127.2552,046
209173.6.128.0/21173.6.128.1 to 173.6.135.254173.6.135.2552,046
210173.6.136.0/21173.6.136.1 to 173.6.143.254173.6.143.2552,046
211173.6.144.0/21173.6.144.1 to 173.6.151.254173.6.151.2552,046
212173.6.152.0/21173.6.152.1 to 173.6.159.254173.6.159.2552,046
213173.6.160.0/21173.6.160.1 to 173.6.167.254173.6.167.2552,046
214173.6.168.0/21173.6.168.1 to 173.6.175.254173.6.175.2552,046
215173.6.176.0/21173.6.176.1 to 173.6.183.254173.6.183.2552,046
216173.6.184.0/21173.6.184.1 to 173.6.191.254173.6.191.2552,046
217173.6.192.0/21173.6.192.1 to 173.6.199.254173.6.199.2552,046
218173.6.200.0/21173.6.200.1 to 173.6.207.254173.6.207.2552,046
219173.6.208.0/21173.6.208.1 to 173.6.215.254173.6.215.2552,046
220173.6.216.0/21173.6.216.1 to 173.6.223.254173.6.223.2552,046
221173.6.224.0/21173.6.224.1 to 173.6.231.254173.6.231.2552,046
222173.6.232.0/21173.6.232.1 to 173.6.239.254173.6.239.2552,046
223173.6.240.0/21173.6.240.1 to 173.6.247.254173.6.247.2552,046
224173.6.248.0/21173.6.248.1 to 173.6.255.254173.6.255.2552,046
225173.7.0.0/21173.7.0.1 to 173.7.7.254173.7.7.2552,046
226173.7.8.0/21173.7.8.1 to 173.7.15.254173.7.15.2552,046
227173.7.16.0/21173.7.16.1 to 173.7.23.254173.7.23.2552,046
228173.7.24.0/21173.7.24.1 to 173.7.31.254173.7.31.2552,046
229173.7.32.0/21173.7.32.1 to 173.7.39.254173.7.39.2552,046
230173.7.40.0/21173.7.40.1 to 173.7.47.254173.7.47.2552,046
231173.7.48.0/21173.7.48.1 to 173.7.55.254173.7.55.2552,046
232173.7.56.0/21173.7.56.1 to 173.7.63.254173.7.63.2552,046
233173.7.64.0/21173.7.64.1 to 173.7.71.254173.7.71.2552,046
234173.7.72.0/21173.7.72.1 to 173.7.79.254173.7.79.2552,046
235173.7.80.0/21173.7.80.1 to 173.7.87.254173.7.87.2552,046
236173.7.88.0/21173.7.88.1 to 173.7.95.254173.7.95.2552,046
237173.7.96.0/21173.7.96.1 to 173.7.103.254173.7.103.2552,046
238173.7.104.0/21173.7.104.1 to 173.7.111.254173.7.111.2552,046
239173.7.112.0/21173.7.112.1 to 173.7.119.254173.7.119.2552,046
240173.7.120.0/21173.7.120.1 to 173.7.127.254173.7.127.2552,046
241173.7.128.0/21173.7.128.1 to 173.7.135.254173.7.135.2552,046
242173.7.136.0/21173.7.136.1 to 173.7.143.254173.7.143.2552,046
243173.7.144.0/21173.7.144.1 to 173.7.151.254173.7.151.2552,046
244173.7.152.0/21173.7.152.1 to 173.7.159.254173.7.159.2552,046
245173.7.160.0/21173.7.160.1 to 173.7.167.254173.7.167.2552,046
246173.7.168.0/21173.7.168.1 to 173.7.175.254173.7.175.2552,046
247173.7.176.0/21173.7.176.1 to 173.7.183.254173.7.183.2552,046
248173.7.184.0/21173.7.184.1 to 173.7.191.254173.7.191.2552,046
249173.7.192.0/21173.7.192.1 to 173.7.199.254173.7.199.2552,046
250173.7.200.0/21173.7.200.1 to 173.7.207.254173.7.207.2552,046
251173.7.208.0/21173.7.208.1 to 173.7.215.254173.7.215.2552,046
252173.7.216.0/21173.7.216.1 to 173.7.223.254173.7.223.2552,046
253173.7.224.0/21173.7.224.1 to 173.7.231.254173.7.231.2552,046
254173.7.232.0/21173.7.232.1 to 173.7.239.254173.7.239.2552,046
255173.7.240.0/21173.7.240.1 to 173.7.247.254173.7.247.2552,046
256173.7.248.0/21173.7.248.1 to 173.7.255.254173.7.255.2552,046

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.