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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.

Network160.166.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
160.166.0.0
Broadcast address
160.167.255.255
First usable
160.166.0.1
Last usable
160.167.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
B (default /16)
As numbers
Hex A0A60000 · Integer 2695233536 to 2695364607
Reverse DNS zones
166.160.in-addr.arpa
167.160.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10100000.10100110.00000000.00000000160.166.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network10100000.10100110.00000000.00000000160.166.0.0
Broadcast10100000.10100111.11111111.11111111160.167.255.255
Split into smaller subnets/24
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

160.166.0.0/15 makes 512 subnets of /24; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1160.166.0.0/24160.166.0.1 to 160.166.0.254160.166.0.255254
2160.166.1.0/24160.166.1.1 to 160.166.1.254160.166.1.255254
3160.166.2.0/24160.166.2.1 to 160.166.2.254160.166.2.255254
4160.166.3.0/24160.166.3.1 to 160.166.3.254160.166.3.255254
5160.166.4.0/24160.166.4.1 to 160.166.4.254160.166.4.255254
6160.166.5.0/24160.166.5.1 to 160.166.5.254160.166.5.255254
7160.166.6.0/24160.166.6.1 to 160.166.6.254160.166.6.255254
8160.166.7.0/24160.166.7.1 to 160.166.7.254160.166.7.255254
9160.166.8.0/24160.166.8.1 to 160.166.8.254160.166.8.255254
10160.166.9.0/24160.166.9.1 to 160.166.9.254160.166.9.255254
11160.166.10.0/24160.166.10.1 to 160.166.10.254160.166.10.255254
12160.166.11.0/24160.166.11.1 to 160.166.11.254160.166.11.255254
13160.166.12.0/24160.166.12.1 to 160.166.12.254160.166.12.255254
14160.166.13.0/24160.166.13.1 to 160.166.13.254160.166.13.255254
15160.166.14.0/24160.166.14.1 to 160.166.14.254160.166.14.255254
16160.166.15.0/24160.166.15.1 to 160.166.15.254160.166.15.255254
17160.166.16.0/24160.166.16.1 to 160.166.16.254160.166.16.255254
18160.166.17.0/24160.166.17.1 to 160.166.17.254160.166.17.255254
19160.166.18.0/24160.166.18.1 to 160.166.18.254160.166.18.255254
20160.166.19.0/24160.166.19.1 to 160.166.19.254160.166.19.255254
21160.166.20.0/24160.166.20.1 to 160.166.20.254160.166.20.255254
22160.166.21.0/24160.166.21.1 to 160.166.21.254160.166.21.255254
23160.166.22.0/24160.166.22.1 to 160.166.22.254160.166.22.255254
24160.166.23.0/24160.166.23.1 to 160.166.23.254160.166.23.255254
25160.166.24.0/24160.166.24.1 to 160.166.24.254160.166.24.255254
26160.166.25.0/24160.166.25.1 to 160.166.25.254160.166.25.255254
27160.166.26.0/24160.166.26.1 to 160.166.26.254160.166.26.255254
28160.166.27.0/24160.166.27.1 to 160.166.27.254160.166.27.255254
29160.166.28.0/24160.166.28.1 to 160.166.28.254160.166.28.255254
30160.166.29.0/24160.166.29.1 to 160.166.29.254160.166.29.255254
31160.166.30.0/24160.166.30.1 to 160.166.30.254160.166.30.255254
32160.166.31.0/24160.166.31.1 to 160.166.31.254160.166.31.255254
33160.166.32.0/24160.166.32.1 to 160.166.32.254160.166.32.255254
34160.166.33.0/24160.166.33.1 to 160.166.33.254160.166.33.255254
35160.166.34.0/24160.166.34.1 to 160.166.34.254160.166.34.255254
36160.166.35.0/24160.166.35.1 to 160.166.35.254160.166.35.255254
37160.166.36.0/24160.166.36.1 to 160.166.36.254160.166.36.255254
38160.166.37.0/24160.166.37.1 to 160.166.37.254160.166.37.255254
39160.166.38.0/24160.166.38.1 to 160.166.38.254160.166.38.255254
40160.166.39.0/24160.166.39.1 to 160.166.39.254160.166.39.255254
41160.166.40.0/24160.166.40.1 to 160.166.40.254160.166.40.255254
42160.166.41.0/24160.166.41.1 to 160.166.41.254160.166.41.255254
43160.166.42.0/24160.166.42.1 to 160.166.42.254160.166.42.255254
44160.166.43.0/24160.166.43.1 to 160.166.43.254160.166.43.255254
45160.166.44.0/24160.166.44.1 to 160.166.44.254160.166.44.255254
46160.166.45.0/24160.166.45.1 to 160.166.45.254160.166.45.255254
47160.166.46.0/24160.166.46.1 to 160.166.46.254160.166.46.255254
48160.166.47.0/24160.166.47.1 to 160.166.47.254160.166.47.255254
49160.166.48.0/24160.166.48.1 to 160.166.48.254160.166.48.255254
50160.166.49.0/24160.166.49.1 to 160.166.49.254160.166.49.255254
51160.166.50.0/24160.166.50.1 to 160.166.50.254160.166.50.255254
52160.166.51.0/24160.166.51.1 to 160.166.51.254160.166.51.255254
53160.166.52.0/24160.166.52.1 to 160.166.52.254160.166.52.255254
54160.166.53.0/24160.166.53.1 to 160.166.53.254160.166.53.255254
55160.166.54.0/24160.166.54.1 to 160.166.54.254160.166.54.255254
56160.166.55.0/24160.166.55.1 to 160.166.55.254160.166.55.255254
57160.166.56.0/24160.166.56.1 to 160.166.56.254160.166.56.255254
58160.166.57.0/24160.166.57.1 to 160.166.57.254160.166.57.255254
59160.166.58.0/24160.166.58.1 to 160.166.58.254160.166.58.255254
60160.166.59.0/24160.166.59.1 to 160.166.59.254160.166.59.255254
61160.166.60.0/24160.166.60.1 to 160.166.60.254160.166.60.255254
62160.166.61.0/24160.166.61.1 to 160.166.61.254160.166.61.255254
63160.166.62.0/24160.166.62.1 to 160.166.62.254160.166.62.255254
64160.166.63.0/24160.166.63.1 to 160.166.63.254160.166.63.255254
65160.166.64.0/24160.166.64.1 to 160.166.64.254160.166.64.255254
66160.166.65.0/24160.166.65.1 to 160.166.65.254160.166.65.255254
67160.166.66.0/24160.166.66.1 to 160.166.66.254160.166.66.255254
68160.166.67.0/24160.166.67.1 to 160.166.67.254160.166.67.255254
69160.166.68.0/24160.166.68.1 to 160.166.68.254160.166.68.255254
70160.166.69.0/24160.166.69.1 to 160.166.69.254160.166.69.255254
71160.166.70.0/24160.166.70.1 to 160.166.70.254160.166.70.255254
72160.166.71.0/24160.166.71.1 to 160.166.71.254160.166.71.255254
73160.166.72.0/24160.166.72.1 to 160.166.72.254160.166.72.255254
74160.166.73.0/24160.166.73.1 to 160.166.73.254160.166.73.255254
75160.166.74.0/24160.166.74.1 to 160.166.74.254160.166.74.255254
76160.166.75.0/24160.166.75.1 to 160.166.75.254160.166.75.255254
77160.166.76.0/24160.166.76.1 to 160.166.76.254160.166.76.255254
78160.166.77.0/24160.166.77.1 to 160.166.77.254160.166.77.255254
79160.166.78.0/24160.166.78.1 to 160.166.78.254160.166.78.255254
80160.166.79.0/24160.166.79.1 to 160.166.79.254160.166.79.255254
81160.166.80.0/24160.166.80.1 to 160.166.80.254160.166.80.255254
82160.166.81.0/24160.166.81.1 to 160.166.81.254160.166.81.255254
83160.166.82.0/24160.166.82.1 to 160.166.82.254160.166.82.255254
84160.166.83.0/24160.166.83.1 to 160.166.83.254160.166.83.255254
85160.166.84.0/24160.166.84.1 to 160.166.84.254160.166.84.255254
86160.166.85.0/24160.166.85.1 to 160.166.85.254160.166.85.255254
87160.166.86.0/24160.166.86.1 to 160.166.86.254160.166.86.255254
88160.166.87.0/24160.166.87.1 to 160.166.87.254160.166.87.255254
89160.166.88.0/24160.166.88.1 to 160.166.88.254160.166.88.255254
90160.166.89.0/24160.166.89.1 to 160.166.89.254160.166.89.255254
91160.166.90.0/24160.166.90.1 to 160.166.90.254160.166.90.255254
92160.166.91.0/24160.166.91.1 to 160.166.91.254160.166.91.255254
93160.166.92.0/24160.166.92.1 to 160.166.92.254160.166.92.255254
94160.166.93.0/24160.166.93.1 to 160.166.93.254160.166.93.255254
95160.166.94.0/24160.166.94.1 to 160.166.94.254160.166.94.255254
96160.166.95.0/24160.166.95.1 to 160.166.95.254160.166.95.255254
97160.166.96.0/24160.166.96.1 to 160.166.96.254160.166.96.255254
98160.166.97.0/24160.166.97.1 to 160.166.97.254160.166.97.255254
99160.166.98.0/24160.166.98.1 to 160.166.98.254160.166.98.255254
100160.166.99.0/24160.166.99.1 to 160.166.99.254160.166.99.255254
101160.166.100.0/24160.166.100.1 to 160.166.100.254160.166.100.255254
102160.166.101.0/24160.166.101.1 to 160.166.101.254160.166.101.255254
103160.166.102.0/24160.166.102.1 to 160.166.102.254160.166.102.255254
104160.166.103.0/24160.166.103.1 to 160.166.103.254160.166.103.255254
105160.166.104.0/24160.166.104.1 to 160.166.104.254160.166.104.255254
106160.166.105.0/24160.166.105.1 to 160.166.105.254160.166.105.255254
107160.166.106.0/24160.166.106.1 to 160.166.106.254160.166.106.255254
108160.166.107.0/24160.166.107.1 to 160.166.107.254160.166.107.255254
109160.166.108.0/24160.166.108.1 to 160.166.108.254160.166.108.255254
110160.166.109.0/24160.166.109.1 to 160.166.109.254160.166.109.255254
111160.166.110.0/24160.166.110.1 to 160.166.110.254160.166.110.255254
112160.166.111.0/24160.166.111.1 to 160.166.111.254160.166.111.255254
113160.166.112.0/24160.166.112.1 to 160.166.112.254160.166.112.255254
114160.166.113.0/24160.166.113.1 to 160.166.113.254160.166.113.255254
115160.166.114.0/24160.166.114.1 to 160.166.114.254160.166.114.255254
116160.166.115.0/24160.166.115.1 to 160.166.115.254160.166.115.255254
117160.166.116.0/24160.166.116.1 to 160.166.116.254160.166.116.255254
118160.166.117.0/24160.166.117.1 to 160.166.117.254160.166.117.255254
119160.166.118.0/24160.166.118.1 to 160.166.118.254160.166.118.255254
120160.166.119.0/24160.166.119.1 to 160.166.119.254160.166.119.255254
121160.166.120.0/24160.166.120.1 to 160.166.120.254160.166.120.255254
122160.166.121.0/24160.166.121.1 to 160.166.121.254160.166.121.255254
123160.166.122.0/24160.166.122.1 to 160.166.122.254160.166.122.255254
124160.166.123.0/24160.166.123.1 to 160.166.123.254160.166.123.255254
125160.166.124.0/24160.166.124.1 to 160.166.124.254160.166.124.255254
126160.166.125.0/24160.166.125.1 to 160.166.125.254160.166.125.255254
127160.166.126.0/24160.166.126.1 to 160.166.126.254160.166.126.255254
128160.166.127.0/24160.166.127.1 to 160.166.127.254160.166.127.255254
129160.166.128.0/24160.166.128.1 to 160.166.128.254160.166.128.255254
130160.166.129.0/24160.166.129.1 to 160.166.129.254160.166.129.255254
131160.166.130.0/24160.166.130.1 to 160.166.130.254160.166.130.255254
132160.166.131.0/24160.166.131.1 to 160.166.131.254160.166.131.255254
133160.166.132.0/24160.166.132.1 to 160.166.132.254160.166.132.255254
134160.166.133.0/24160.166.133.1 to 160.166.133.254160.166.133.255254
135160.166.134.0/24160.166.134.1 to 160.166.134.254160.166.134.255254
136160.166.135.0/24160.166.135.1 to 160.166.135.254160.166.135.255254
137160.166.136.0/24160.166.136.1 to 160.166.136.254160.166.136.255254
138160.166.137.0/24160.166.137.1 to 160.166.137.254160.166.137.255254
139160.166.138.0/24160.166.138.1 to 160.166.138.254160.166.138.255254
140160.166.139.0/24160.166.139.1 to 160.166.139.254160.166.139.255254
141160.166.140.0/24160.166.140.1 to 160.166.140.254160.166.140.255254
142160.166.141.0/24160.166.141.1 to 160.166.141.254160.166.141.255254
143160.166.142.0/24160.166.142.1 to 160.166.142.254160.166.142.255254
144160.166.143.0/24160.166.143.1 to 160.166.143.254160.166.143.255254
145160.166.144.0/24160.166.144.1 to 160.166.144.254160.166.144.255254
146160.166.145.0/24160.166.145.1 to 160.166.145.254160.166.145.255254
147160.166.146.0/24160.166.146.1 to 160.166.146.254160.166.146.255254
148160.166.147.0/24160.166.147.1 to 160.166.147.254160.166.147.255254
149160.166.148.0/24160.166.148.1 to 160.166.148.254160.166.148.255254
150160.166.149.0/24160.166.149.1 to 160.166.149.254160.166.149.255254
151160.166.150.0/24160.166.150.1 to 160.166.150.254160.166.150.255254
152160.166.151.0/24160.166.151.1 to 160.166.151.254160.166.151.255254
153160.166.152.0/24160.166.152.1 to 160.166.152.254160.166.152.255254
154160.166.153.0/24160.166.153.1 to 160.166.153.254160.166.153.255254
155160.166.154.0/24160.166.154.1 to 160.166.154.254160.166.154.255254
156160.166.155.0/24160.166.155.1 to 160.166.155.254160.166.155.255254
157160.166.156.0/24160.166.156.1 to 160.166.156.254160.166.156.255254
158160.166.157.0/24160.166.157.1 to 160.166.157.254160.166.157.255254
159160.166.158.0/24160.166.158.1 to 160.166.158.254160.166.158.255254
160160.166.159.0/24160.166.159.1 to 160.166.159.254160.166.159.255254
161160.166.160.0/24160.166.160.1 to 160.166.160.254160.166.160.255254
162160.166.161.0/24160.166.161.1 to 160.166.161.254160.166.161.255254
163160.166.162.0/24160.166.162.1 to 160.166.162.254160.166.162.255254
164160.166.163.0/24160.166.163.1 to 160.166.163.254160.166.163.255254
165160.166.164.0/24160.166.164.1 to 160.166.164.254160.166.164.255254
166160.166.165.0/24160.166.165.1 to 160.166.165.254160.166.165.255254
167160.166.166.0/24160.166.166.1 to 160.166.166.254160.166.166.255254
168160.166.167.0/24160.166.167.1 to 160.166.167.254160.166.167.255254
169160.166.168.0/24160.166.168.1 to 160.166.168.254160.166.168.255254
170160.166.169.0/24160.166.169.1 to 160.166.169.254160.166.169.255254
171160.166.170.0/24160.166.170.1 to 160.166.170.254160.166.170.255254
172160.166.171.0/24160.166.171.1 to 160.166.171.254160.166.171.255254
173160.166.172.0/24160.166.172.1 to 160.166.172.254160.166.172.255254
174160.166.173.0/24160.166.173.1 to 160.166.173.254160.166.173.255254
175160.166.174.0/24160.166.174.1 to 160.166.174.254160.166.174.255254
176160.166.175.0/24160.166.175.1 to 160.166.175.254160.166.175.255254
177160.166.176.0/24160.166.176.1 to 160.166.176.254160.166.176.255254
178160.166.177.0/24160.166.177.1 to 160.166.177.254160.166.177.255254
179160.166.178.0/24160.166.178.1 to 160.166.178.254160.166.178.255254
180160.166.179.0/24160.166.179.1 to 160.166.179.254160.166.179.255254
181160.166.180.0/24160.166.180.1 to 160.166.180.254160.166.180.255254
182160.166.181.0/24160.166.181.1 to 160.166.181.254160.166.181.255254
183160.166.182.0/24160.166.182.1 to 160.166.182.254160.166.182.255254
184160.166.183.0/24160.166.183.1 to 160.166.183.254160.166.183.255254
185160.166.184.0/24160.166.184.1 to 160.166.184.254160.166.184.255254
186160.166.185.0/24160.166.185.1 to 160.166.185.254160.166.185.255254
187160.166.186.0/24160.166.186.1 to 160.166.186.254160.166.186.255254
188160.166.187.0/24160.166.187.1 to 160.166.187.254160.166.187.255254
189160.166.188.0/24160.166.188.1 to 160.166.188.254160.166.188.255254
190160.166.189.0/24160.166.189.1 to 160.166.189.254160.166.189.255254
191160.166.190.0/24160.166.190.1 to 160.166.190.254160.166.190.255254
192160.166.191.0/24160.166.191.1 to 160.166.191.254160.166.191.255254
193160.166.192.0/24160.166.192.1 to 160.166.192.254160.166.192.255254
194160.166.193.0/24160.166.193.1 to 160.166.193.254160.166.193.255254
195160.166.194.0/24160.166.194.1 to 160.166.194.254160.166.194.255254
196160.166.195.0/24160.166.195.1 to 160.166.195.254160.166.195.255254
197160.166.196.0/24160.166.196.1 to 160.166.196.254160.166.196.255254
198160.166.197.0/24160.166.197.1 to 160.166.197.254160.166.197.255254
199160.166.198.0/24160.166.198.1 to 160.166.198.254160.166.198.255254
200160.166.199.0/24160.166.199.1 to 160.166.199.254160.166.199.255254
201160.166.200.0/24160.166.200.1 to 160.166.200.254160.166.200.255254
202160.166.201.0/24160.166.201.1 to 160.166.201.254160.166.201.255254
203160.166.202.0/24160.166.202.1 to 160.166.202.254160.166.202.255254
204160.166.203.0/24160.166.203.1 to 160.166.203.254160.166.203.255254
205160.166.204.0/24160.166.204.1 to 160.166.204.254160.166.204.255254
206160.166.205.0/24160.166.205.1 to 160.166.205.254160.166.205.255254
207160.166.206.0/24160.166.206.1 to 160.166.206.254160.166.206.255254
208160.166.207.0/24160.166.207.1 to 160.166.207.254160.166.207.255254
209160.166.208.0/24160.166.208.1 to 160.166.208.254160.166.208.255254
210160.166.209.0/24160.166.209.1 to 160.166.209.254160.166.209.255254
211160.166.210.0/24160.166.210.1 to 160.166.210.254160.166.210.255254
212160.166.211.0/24160.166.211.1 to 160.166.211.254160.166.211.255254
213160.166.212.0/24160.166.212.1 to 160.166.212.254160.166.212.255254
214160.166.213.0/24160.166.213.1 to 160.166.213.254160.166.213.255254
215160.166.214.0/24160.166.214.1 to 160.166.214.254160.166.214.255254
216160.166.215.0/24160.166.215.1 to 160.166.215.254160.166.215.255254
217160.166.216.0/24160.166.216.1 to 160.166.216.254160.166.216.255254
218160.166.217.0/24160.166.217.1 to 160.166.217.254160.166.217.255254
219160.166.218.0/24160.166.218.1 to 160.166.218.254160.166.218.255254
220160.166.219.0/24160.166.219.1 to 160.166.219.254160.166.219.255254
221160.166.220.0/24160.166.220.1 to 160.166.220.254160.166.220.255254
222160.166.221.0/24160.166.221.1 to 160.166.221.254160.166.221.255254
223160.166.222.0/24160.166.222.1 to 160.166.222.254160.166.222.255254
224160.166.223.0/24160.166.223.1 to 160.166.223.254160.166.223.255254
225160.166.224.0/24160.166.224.1 to 160.166.224.254160.166.224.255254
226160.166.225.0/24160.166.225.1 to 160.166.225.254160.166.225.255254
227160.166.226.0/24160.166.226.1 to 160.166.226.254160.166.226.255254
228160.166.227.0/24160.166.227.1 to 160.166.227.254160.166.227.255254
229160.166.228.0/24160.166.228.1 to 160.166.228.254160.166.228.255254
230160.166.229.0/24160.166.229.1 to 160.166.229.254160.166.229.255254
231160.166.230.0/24160.166.230.1 to 160.166.230.254160.166.230.255254
232160.166.231.0/24160.166.231.1 to 160.166.231.254160.166.231.255254
233160.166.232.0/24160.166.232.1 to 160.166.232.254160.166.232.255254
234160.166.233.0/24160.166.233.1 to 160.166.233.254160.166.233.255254
235160.166.234.0/24160.166.234.1 to 160.166.234.254160.166.234.255254
236160.166.235.0/24160.166.235.1 to 160.166.235.254160.166.235.255254
237160.166.236.0/24160.166.236.1 to 160.166.236.254160.166.236.255254
238160.166.237.0/24160.166.237.1 to 160.166.237.254160.166.237.255254
239160.166.238.0/24160.166.238.1 to 160.166.238.254160.166.238.255254
240160.166.239.0/24160.166.239.1 to 160.166.239.254160.166.239.255254
241160.166.240.0/24160.166.240.1 to 160.166.240.254160.166.240.255254
242160.166.241.0/24160.166.241.1 to 160.166.241.254160.166.241.255254
243160.166.242.0/24160.166.242.1 to 160.166.242.254160.166.242.255254
244160.166.243.0/24160.166.243.1 to 160.166.243.254160.166.243.255254
245160.166.244.0/24160.166.244.1 to 160.166.244.254160.166.244.255254
246160.166.245.0/24160.166.245.1 to 160.166.245.254160.166.245.255254
247160.166.246.0/24160.166.246.1 to 160.166.246.254160.166.246.255254
248160.166.247.0/24160.166.247.1 to 160.166.247.254160.166.247.255254
249160.166.248.0/24160.166.248.1 to 160.166.248.254160.166.248.255254
250160.166.249.0/24160.166.249.1 to 160.166.249.254160.166.249.255254
251160.166.250.0/24160.166.250.1 to 160.166.250.254160.166.250.255254
252160.166.251.0/24160.166.251.1 to 160.166.251.254160.166.251.255254
253160.166.252.0/24160.166.252.1 to 160.166.252.254160.166.252.255254
254160.166.253.0/24160.166.253.1 to 160.166.253.254160.166.253.255254
255160.166.254.0/24160.166.254.1 to 160.166.254.254160.166.254.255254
256160.166.255.0/24160.166.255.1 to 160.166.255.254160.166.255.255254

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.