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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.

Network224.170.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
224.170.0.0
Broadcast address
224.171.255.255
First usable
224.170.0.1
Last usable
224.171.255.254
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
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E0AA0000 · Integer 3769237504 to 3769368575
Reverse DNS zones
170.224.in-addr.arpa
171.224.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
Address11100000.10101010.00000000.00000000224.170.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network11100000.10101010.00000000.00000000224.170.0.0
Broadcast11100000.10101011.11111111.11111111224.171.255.255
Split into smaller subnets/23
/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)

224.170.0.0/15 makes 256 subnets of /23.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1224.170.0.0/23224.170.0.1 to 224.170.1.254224.170.1.255510
2224.170.2.0/23224.170.2.1 to 224.170.3.254224.170.3.255510
3224.170.4.0/23224.170.4.1 to 224.170.5.254224.170.5.255510
4224.170.6.0/23224.170.6.1 to 224.170.7.254224.170.7.255510
5224.170.8.0/23224.170.8.1 to 224.170.9.254224.170.9.255510
6224.170.10.0/23224.170.10.1 to 224.170.11.254224.170.11.255510
7224.170.12.0/23224.170.12.1 to 224.170.13.254224.170.13.255510
8224.170.14.0/23224.170.14.1 to 224.170.15.254224.170.15.255510
9224.170.16.0/23224.170.16.1 to 224.170.17.254224.170.17.255510
10224.170.18.0/23224.170.18.1 to 224.170.19.254224.170.19.255510
11224.170.20.0/23224.170.20.1 to 224.170.21.254224.170.21.255510
12224.170.22.0/23224.170.22.1 to 224.170.23.254224.170.23.255510
13224.170.24.0/23224.170.24.1 to 224.170.25.254224.170.25.255510
14224.170.26.0/23224.170.26.1 to 224.170.27.254224.170.27.255510
15224.170.28.0/23224.170.28.1 to 224.170.29.254224.170.29.255510
16224.170.30.0/23224.170.30.1 to 224.170.31.254224.170.31.255510
17224.170.32.0/23224.170.32.1 to 224.170.33.254224.170.33.255510
18224.170.34.0/23224.170.34.1 to 224.170.35.254224.170.35.255510
19224.170.36.0/23224.170.36.1 to 224.170.37.254224.170.37.255510
20224.170.38.0/23224.170.38.1 to 224.170.39.254224.170.39.255510
21224.170.40.0/23224.170.40.1 to 224.170.41.254224.170.41.255510
22224.170.42.0/23224.170.42.1 to 224.170.43.254224.170.43.255510
23224.170.44.0/23224.170.44.1 to 224.170.45.254224.170.45.255510
24224.170.46.0/23224.170.46.1 to 224.170.47.254224.170.47.255510
25224.170.48.0/23224.170.48.1 to 224.170.49.254224.170.49.255510
26224.170.50.0/23224.170.50.1 to 224.170.51.254224.170.51.255510
27224.170.52.0/23224.170.52.1 to 224.170.53.254224.170.53.255510
28224.170.54.0/23224.170.54.1 to 224.170.55.254224.170.55.255510
29224.170.56.0/23224.170.56.1 to 224.170.57.254224.170.57.255510
30224.170.58.0/23224.170.58.1 to 224.170.59.254224.170.59.255510
31224.170.60.0/23224.170.60.1 to 224.170.61.254224.170.61.255510
32224.170.62.0/23224.170.62.1 to 224.170.63.254224.170.63.255510
33224.170.64.0/23224.170.64.1 to 224.170.65.254224.170.65.255510
34224.170.66.0/23224.170.66.1 to 224.170.67.254224.170.67.255510
35224.170.68.0/23224.170.68.1 to 224.170.69.254224.170.69.255510
36224.170.70.0/23224.170.70.1 to 224.170.71.254224.170.71.255510
37224.170.72.0/23224.170.72.1 to 224.170.73.254224.170.73.255510
38224.170.74.0/23224.170.74.1 to 224.170.75.254224.170.75.255510
39224.170.76.0/23224.170.76.1 to 224.170.77.254224.170.77.255510
40224.170.78.0/23224.170.78.1 to 224.170.79.254224.170.79.255510
41224.170.80.0/23224.170.80.1 to 224.170.81.254224.170.81.255510
42224.170.82.0/23224.170.82.1 to 224.170.83.254224.170.83.255510
43224.170.84.0/23224.170.84.1 to 224.170.85.254224.170.85.255510
44224.170.86.0/23224.170.86.1 to 224.170.87.254224.170.87.255510
45224.170.88.0/23224.170.88.1 to 224.170.89.254224.170.89.255510
46224.170.90.0/23224.170.90.1 to 224.170.91.254224.170.91.255510
47224.170.92.0/23224.170.92.1 to 224.170.93.254224.170.93.255510
48224.170.94.0/23224.170.94.1 to 224.170.95.254224.170.95.255510
49224.170.96.0/23224.170.96.1 to 224.170.97.254224.170.97.255510
50224.170.98.0/23224.170.98.1 to 224.170.99.254224.170.99.255510
51224.170.100.0/23224.170.100.1 to 224.170.101.254224.170.101.255510
52224.170.102.0/23224.170.102.1 to 224.170.103.254224.170.103.255510
53224.170.104.0/23224.170.104.1 to 224.170.105.254224.170.105.255510
54224.170.106.0/23224.170.106.1 to 224.170.107.254224.170.107.255510
55224.170.108.0/23224.170.108.1 to 224.170.109.254224.170.109.255510
56224.170.110.0/23224.170.110.1 to 224.170.111.254224.170.111.255510
57224.170.112.0/23224.170.112.1 to 224.170.113.254224.170.113.255510
58224.170.114.0/23224.170.114.1 to 224.170.115.254224.170.115.255510
59224.170.116.0/23224.170.116.1 to 224.170.117.254224.170.117.255510
60224.170.118.0/23224.170.118.1 to 224.170.119.254224.170.119.255510
61224.170.120.0/23224.170.120.1 to 224.170.121.254224.170.121.255510
62224.170.122.0/23224.170.122.1 to 224.170.123.254224.170.123.255510
63224.170.124.0/23224.170.124.1 to 224.170.125.254224.170.125.255510
64224.170.126.0/23224.170.126.1 to 224.170.127.254224.170.127.255510
65224.170.128.0/23224.170.128.1 to 224.170.129.254224.170.129.255510
66224.170.130.0/23224.170.130.1 to 224.170.131.254224.170.131.255510
67224.170.132.0/23224.170.132.1 to 224.170.133.254224.170.133.255510
68224.170.134.0/23224.170.134.1 to 224.170.135.254224.170.135.255510
69224.170.136.0/23224.170.136.1 to 224.170.137.254224.170.137.255510
70224.170.138.0/23224.170.138.1 to 224.170.139.254224.170.139.255510
71224.170.140.0/23224.170.140.1 to 224.170.141.254224.170.141.255510
72224.170.142.0/23224.170.142.1 to 224.170.143.254224.170.143.255510
73224.170.144.0/23224.170.144.1 to 224.170.145.254224.170.145.255510
74224.170.146.0/23224.170.146.1 to 224.170.147.254224.170.147.255510
75224.170.148.0/23224.170.148.1 to 224.170.149.254224.170.149.255510
76224.170.150.0/23224.170.150.1 to 224.170.151.254224.170.151.255510
77224.170.152.0/23224.170.152.1 to 224.170.153.254224.170.153.255510
78224.170.154.0/23224.170.154.1 to 224.170.155.254224.170.155.255510
79224.170.156.0/23224.170.156.1 to 224.170.157.254224.170.157.255510
80224.170.158.0/23224.170.158.1 to 224.170.159.254224.170.159.255510
81224.170.160.0/23224.170.160.1 to 224.170.161.254224.170.161.255510
82224.170.162.0/23224.170.162.1 to 224.170.163.254224.170.163.255510
83224.170.164.0/23224.170.164.1 to 224.170.165.254224.170.165.255510
84224.170.166.0/23224.170.166.1 to 224.170.167.254224.170.167.255510
85224.170.168.0/23224.170.168.1 to 224.170.169.254224.170.169.255510
86224.170.170.0/23224.170.170.1 to 224.170.171.254224.170.171.255510
87224.170.172.0/23224.170.172.1 to 224.170.173.254224.170.173.255510
88224.170.174.0/23224.170.174.1 to 224.170.175.254224.170.175.255510
89224.170.176.0/23224.170.176.1 to 224.170.177.254224.170.177.255510
90224.170.178.0/23224.170.178.1 to 224.170.179.254224.170.179.255510
91224.170.180.0/23224.170.180.1 to 224.170.181.254224.170.181.255510
92224.170.182.0/23224.170.182.1 to 224.170.183.254224.170.183.255510
93224.170.184.0/23224.170.184.1 to 224.170.185.254224.170.185.255510
94224.170.186.0/23224.170.186.1 to 224.170.187.254224.170.187.255510
95224.170.188.0/23224.170.188.1 to 224.170.189.254224.170.189.255510
96224.170.190.0/23224.170.190.1 to 224.170.191.254224.170.191.255510
97224.170.192.0/23224.170.192.1 to 224.170.193.254224.170.193.255510
98224.170.194.0/23224.170.194.1 to 224.170.195.254224.170.195.255510
99224.170.196.0/23224.170.196.1 to 224.170.197.254224.170.197.255510
100224.170.198.0/23224.170.198.1 to 224.170.199.254224.170.199.255510
101224.170.200.0/23224.170.200.1 to 224.170.201.254224.170.201.255510
102224.170.202.0/23224.170.202.1 to 224.170.203.254224.170.203.255510
103224.170.204.0/23224.170.204.1 to 224.170.205.254224.170.205.255510
104224.170.206.0/23224.170.206.1 to 224.170.207.254224.170.207.255510
105224.170.208.0/23224.170.208.1 to 224.170.209.254224.170.209.255510
106224.170.210.0/23224.170.210.1 to 224.170.211.254224.170.211.255510
107224.170.212.0/23224.170.212.1 to 224.170.213.254224.170.213.255510
108224.170.214.0/23224.170.214.1 to 224.170.215.254224.170.215.255510
109224.170.216.0/23224.170.216.1 to 224.170.217.254224.170.217.255510
110224.170.218.0/23224.170.218.1 to 224.170.219.254224.170.219.255510
111224.170.220.0/23224.170.220.1 to 224.170.221.254224.170.221.255510
112224.170.222.0/23224.170.222.1 to 224.170.223.254224.170.223.255510
113224.170.224.0/23224.170.224.1 to 224.170.225.254224.170.225.255510
114224.170.226.0/23224.170.226.1 to 224.170.227.254224.170.227.255510
115224.170.228.0/23224.170.228.1 to 224.170.229.254224.170.229.255510
116224.170.230.0/23224.170.230.1 to 224.170.231.254224.170.231.255510
117224.170.232.0/23224.170.232.1 to 224.170.233.254224.170.233.255510
118224.170.234.0/23224.170.234.1 to 224.170.235.254224.170.235.255510
119224.170.236.0/23224.170.236.1 to 224.170.237.254224.170.237.255510
120224.170.238.0/23224.170.238.1 to 224.170.239.254224.170.239.255510
121224.170.240.0/23224.170.240.1 to 224.170.241.254224.170.241.255510
122224.170.242.0/23224.170.242.1 to 224.170.243.254224.170.243.255510
123224.170.244.0/23224.170.244.1 to 224.170.245.254224.170.245.255510
124224.170.246.0/23224.170.246.1 to 224.170.247.254224.170.247.255510
125224.170.248.0/23224.170.248.1 to 224.170.249.254224.170.249.255510
126224.170.250.0/23224.170.250.1 to 224.170.251.254224.170.251.255510
127224.170.252.0/23224.170.252.1 to 224.170.253.254224.170.253.255510
128224.170.254.0/23224.170.254.1 to 224.170.255.254224.170.255.255510
129224.171.0.0/23224.171.0.1 to 224.171.1.254224.171.1.255510
130224.171.2.0/23224.171.2.1 to 224.171.3.254224.171.3.255510
131224.171.4.0/23224.171.4.1 to 224.171.5.254224.171.5.255510
132224.171.6.0/23224.171.6.1 to 224.171.7.254224.171.7.255510
133224.171.8.0/23224.171.8.1 to 224.171.9.254224.171.9.255510
134224.171.10.0/23224.171.10.1 to 224.171.11.254224.171.11.255510
135224.171.12.0/23224.171.12.1 to 224.171.13.254224.171.13.255510
136224.171.14.0/23224.171.14.1 to 224.171.15.254224.171.15.255510
137224.171.16.0/23224.171.16.1 to 224.171.17.254224.171.17.255510
138224.171.18.0/23224.171.18.1 to 224.171.19.254224.171.19.255510
139224.171.20.0/23224.171.20.1 to 224.171.21.254224.171.21.255510
140224.171.22.0/23224.171.22.1 to 224.171.23.254224.171.23.255510
141224.171.24.0/23224.171.24.1 to 224.171.25.254224.171.25.255510
142224.171.26.0/23224.171.26.1 to 224.171.27.254224.171.27.255510
143224.171.28.0/23224.171.28.1 to 224.171.29.254224.171.29.255510
144224.171.30.0/23224.171.30.1 to 224.171.31.254224.171.31.255510
145224.171.32.0/23224.171.32.1 to 224.171.33.254224.171.33.255510
146224.171.34.0/23224.171.34.1 to 224.171.35.254224.171.35.255510
147224.171.36.0/23224.171.36.1 to 224.171.37.254224.171.37.255510
148224.171.38.0/23224.171.38.1 to 224.171.39.254224.171.39.255510
149224.171.40.0/23224.171.40.1 to 224.171.41.254224.171.41.255510
150224.171.42.0/23224.171.42.1 to 224.171.43.254224.171.43.255510
151224.171.44.0/23224.171.44.1 to 224.171.45.254224.171.45.255510
152224.171.46.0/23224.171.46.1 to 224.171.47.254224.171.47.255510
153224.171.48.0/23224.171.48.1 to 224.171.49.254224.171.49.255510
154224.171.50.0/23224.171.50.1 to 224.171.51.254224.171.51.255510
155224.171.52.0/23224.171.52.1 to 224.171.53.254224.171.53.255510
156224.171.54.0/23224.171.54.1 to 224.171.55.254224.171.55.255510
157224.171.56.0/23224.171.56.1 to 224.171.57.254224.171.57.255510
158224.171.58.0/23224.171.58.1 to 224.171.59.254224.171.59.255510
159224.171.60.0/23224.171.60.1 to 224.171.61.254224.171.61.255510
160224.171.62.0/23224.171.62.1 to 224.171.63.254224.171.63.255510
161224.171.64.0/23224.171.64.1 to 224.171.65.254224.171.65.255510
162224.171.66.0/23224.171.66.1 to 224.171.67.254224.171.67.255510
163224.171.68.0/23224.171.68.1 to 224.171.69.254224.171.69.255510
164224.171.70.0/23224.171.70.1 to 224.171.71.254224.171.71.255510
165224.171.72.0/23224.171.72.1 to 224.171.73.254224.171.73.255510
166224.171.74.0/23224.171.74.1 to 224.171.75.254224.171.75.255510
167224.171.76.0/23224.171.76.1 to 224.171.77.254224.171.77.255510
168224.171.78.0/23224.171.78.1 to 224.171.79.254224.171.79.255510
169224.171.80.0/23224.171.80.1 to 224.171.81.254224.171.81.255510
170224.171.82.0/23224.171.82.1 to 224.171.83.254224.171.83.255510
171224.171.84.0/23224.171.84.1 to 224.171.85.254224.171.85.255510
172224.171.86.0/23224.171.86.1 to 224.171.87.254224.171.87.255510
173224.171.88.0/23224.171.88.1 to 224.171.89.254224.171.89.255510
174224.171.90.0/23224.171.90.1 to 224.171.91.254224.171.91.255510
175224.171.92.0/23224.171.92.1 to 224.171.93.254224.171.93.255510
176224.171.94.0/23224.171.94.1 to 224.171.95.254224.171.95.255510
177224.171.96.0/23224.171.96.1 to 224.171.97.254224.171.97.255510
178224.171.98.0/23224.171.98.1 to 224.171.99.254224.171.99.255510
179224.171.100.0/23224.171.100.1 to 224.171.101.254224.171.101.255510
180224.171.102.0/23224.171.102.1 to 224.171.103.254224.171.103.255510
181224.171.104.0/23224.171.104.1 to 224.171.105.254224.171.105.255510
182224.171.106.0/23224.171.106.1 to 224.171.107.254224.171.107.255510
183224.171.108.0/23224.171.108.1 to 224.171.109.254224.171.109.255510
184224.171.110.0/23224.171.110.1 to 224.171.111.254224.171.111.255510
185224.171.112.0/23224.171.112.1 to 224.171.113.254224.171.113.255510
186224.171.114.0/23224.171.114.1 to 224.171.115.254224.171.115.255510
187224.171.116.0/23224.171.116.1 to 224.171.117.254224.171.117.255510
188224.171.118.0/23224.171.118.1 to 224.171.119.254224.171.119.255510
189224.171.120.0/23224.171.120.1 to 224.171.121.254224.171.121.255510
190224.171.122.0/23224.171.122.1 to 224.171.123.254224.171.123.255510
191224.171.124.0/23224.171.124.1 to 224.171.125.254224.171.125.255510
192224.171.126.0/23224.171.126.1 to 224.171.127.254224.171.127.255510
193224.171.128.0/23224.171.128.1 to 224.171.129.254224.171.129.255510
194224.171.130.0/23224.171.130.1 to 224.171.131.254224.171.131.255510
195224.171.132.0/23224.171.132.1 to 224.171.133.254224.171.133.255510
196224.171.134.0/23224.171.134.1 to 224.171.135.254224.171.135.255510
197224.171.136.0/23224.171.136.1 to 224.171.137.254224.171.137.255510
198224.171.138.0/23224.171.138.1 to 224.171.139.254224.171.139.255510
199224.171.140.0/23224.171.140.1 to 224.171.141.254224.171.141.255510
200224.171.142.0/23224.171.142.1 to 224.171.143.254224.171.143.255510
201224.171.144.0/23224.171.144.1 to 224.171.145.254224.171.145.255510
202224.171.146.0/23224.171.146.1 to 224.171.147.254224.171.147.255510
203224.171.148.0/23224.171.148.1 to 224.171.149.254224.171.149.255510
204224.171.150.0/23224.171.150.1 to 224.171.151.254224.171.151.255510
205224.171.152.0/23224.171.152.1 to 224.171.153.254224.171.153.255510
206224.171.154.0/23224.171.154.1 to 224.171.155.254224.171.155.255510
207224.171.156.0/23224.171.156.1 to 224.171.157.254224.171.157.255510
208224.171.158.0/23224.171.158.1 to 224.171.159.254224.171.159.255510
209224.171.160.0/23224.171.160.1 to 224.171.161.254224.171.161.255510
210224.171.162.0/23224.171.162.1 to 224.171.163.254224.171.163.255510
211224.171.164.0/23224.171.164.1 to 224.171.165.254224.171.165.255510
212224.171.166.0/23224.171.166.1 to 224.171.167.254224.171.167.255510
213224.171.168.0/23224.171.168.1 to 224.171.169.254224.171.169.255510
214224.171.170.0/23224.171.170.1 to 224.171.171.254224.171.171.255510
215224.171.172.0/23224.171.172.1 to 224.171.173.254224.171.173.255510
216224.171.174.0/23224.171.174.1 to 224.171.175.254224.171.175.255510
217224.171.176.0/23224.171.176.1 to 224.171.177.254224.171.177.255510
218224.171.178.0/23224.171.178.1 to 224.171.179.254224.171.179.255510
219224.171.180.0/23224.171.180.1 to 224.171.181.254224.171.181.255510
220224.171.182.0/23224.171.182.1 to 224.171.183.254224.171.183.255510
221224.171.184.0/23224.171.184.1 to 224.171.185.254224.171.185.255510
222224.171.186.0/23224.171.186.1 to 224.171.187.254224.171.187.255510
223224.171.188.0/23224.171.188.1 to 224.171.189.254224.171.189.255510
224224.171.190.0/23224.171.190.1 to 224.171.191.254224.171.191.255510
225224.171.192.0/23224.171.192.1 to 224.171.193.254224.171.193.255510
226224.171.194.0/23224.171.194.1 to 224.171.195.254224.171.195.255510
227224.171.196.0/23224.171.196.1 to 224.171.197.254224.171.197.255510
228224.171.198.0/23224.171.198.1 to 224.171.199.254224.171.199.255510
229224.171.200.0/23224.171.200.1 to 224.171.201.254224.171.201.255510
230224.171.202.0/23224.171.202.1 to 224.171.203.254224.171.203.255510
231224.171.204.0/23224.171.204.1 to 224.171.205.254224.171.205.255510
232224.171.206.0/23224.171.206.1 to 224.171.207.254224.171.207.255510
233224.171.208.0/23224.171.208.1 to 224.171.209.254224.171.209.255510
234224.171.210.0/23224.171.210.1 to 224.171.211.254224.171.211.255510
235224.171.212.0/23224.171.212.1 to 224.171.213.254224.171.213.255510
236224.171.214.0/23224.171.214.1 to 224.171.215.254224.171.215.255510
237224.171.216.0/23224.171.216.1 to 224.171.217.254224.171.217.255510
238224.171.218.0/23224.171.218.1 to 224.171.219.254224.171.219.255510
239224.171.220.0/23224.171.220.1 to 224.171.221.254224.171.221.255510
240224.171.222.0/23224.171.222.1 to 224.171.223.254224.171.223.255510
241224.171.224.0/23224.171.224.1 to 224.171.225.254224.171.225.255510
242224.171.226.0/23224.171.226.1 to 224.171.227.254224.171.227.255510
243224.171.228.0/23224.171.228.1 to 224.171.229.254224.171.229.255510
244224.171.230.0/23224.171.230.1 to 224.171.231.254224.171.231.255510
245224.171.232.0/23224.171.232.1 to 224.171.233.254224.171.233.255510
246224.171.234.0/23224.171.234.1 to 224.171.235.254224.171.235.255510
247224.171.236.0/23224.171.236.1 to 224.171.237.254224.171.237.255510
248224.171.238.0/23224.171.238.1 to 224.171.239.254224.171.239.255510
249224.171.240.0/23224.171.240.1 to 224.171.241.254224.171.241.255510
250224.171.242.0/23224.171.242.1 to 224.171.243.254224.171.243.255510
251224.171.244.0/23224.171.244.1 to 224.171.245.254224.171.245.255510
252224.171.246.0/23224.171.246.1 to 224.171.247.254224.171.247.255510
253224.171.248.0/23224.171.248.1 to 224.171.249.254224.171.249.255510
254224.171.250.0/23224.171.250.1 to 224.171.251.254224.171.251.255510
255224.171.252.0/23224.171.252.1 to 224.171.253.254224.171.253.255510
256224.171.254.0/23224.171.254.1 to 224.171.255.254224.171.255.255510

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.