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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.

Network241.0.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
241.0.0.0
Broadcast address
241.7.255.255
First usable
241.0.0.1
Last usable
241.7.255.254
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
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex F1000000 · Integer 4043309056 to 4043833343
Reverse DNS zones
0.241.in-addr.arpa
1.241.in-addr.arpa
2.241.in-addr.arpa
3.241.in-addr.arpa
4.241.in-addr.arpa
5.241.in-addr.arpa
6.241.in-addr.arpa
7.241.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
Address11110001.00000000.00000000.00000000241.0.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network11110001.00000000.00000000.00000000241.0.0.0
Broadcast11110001.00000111.11111111.11111111241.7.255.255
Split into smaller subnets/23
/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)

241.0.0.0/13 makes 1,024 subnets of /23; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1241.0.0.0/23241.0.0.1 to 241.0.1.254241.0.1.255510
2241.0.2.0/23241.0.2.1 to 241.0.3.254241.0.3.255510
3241.0.4.0/23241.0.4.1 to 241.0.5.254241.0.5.255510
4241.0.6.0/23241.0.6.1 to 241.0.7.254241.0.7.255510
5241.0.8.0/23241.0.8.1 to 241.0.9.254241.0.9.255510
6241.0.10.0/23241.0.10.1 to 241.0.11.254241.0.11.255510
7241.0.12.0/23241.0.12.1 to 241.0.13.254241.0.13.255510
8241.0.14.0/23241.0.14.1 to 241.0.15.254241.0.15.255510
9241.0.16.0/23241.0.16.1 to 241.0.17.254241.0.17.255510
10241.0.18.0/23241.0.18.1 to 241.0.19.254241.0.19.255510
11241.0.20.0/23241.0.20.1 to 241.0.21.254241.0.21.255510
12241.0.22.0/23241.0.22.1 to 241.0.23.254241.0.23.255510
13241.0.24.0/23241.0.24.1 to 241.0.25.254241.0.25.255510
14241.0.26.0/23241.0.26.1 to 241.0.27.254241.0.27.255510
15241.0.28.0/23241.0.28.1 to 241.0.29.254241.0.29.255510
16241.0.30.0/23241.0.30.1 to 241.0.31.254241.0.31.255510
17241.0.32.0/23241.0.32.1 to 241.0.33.254241.0.33.255510
18241.0.34.0/23241.0.34.1 to 241.0.35.254241.0.35.255510
19241.0.36.0/23241.0.36.1 to 241.0.37.254241.0.37.255510
20241.0.38.0/23241.0.38.1 to 241.0.39.254241.0.39.255510
21241.0.40.0/23241.0.40.1 to 241.0.41.254241.0.41.255510
22241.0.42.0/23241.0.42.1 to 241.0.43.254241.0.43.255510
23241.0.44.0/23241.0.44.1 to 241.0.45.254241.0.45.255510
24241.0.46.0/23241.0.46.1 to 241.0.47.254241.0.47.255510
25241.0.48.0/23241.0.48.1 to 241.0.49.254241.0.49.255510
26241.0.50.0/23241.0.50.1 to 241.0.51.254241.0.51.255510
27241.0.52.0/23241.0.52.1 to 241.0.53.254241.0.53.255510
28241.0.54.0/23241.0.54.1 to 241.0.55.254241.0.55.255510
29241.0.56.0/23241.0.56.1 to 241.0.57.254241.0.57.255510
30241.0.58.0/23241.0.58.1 to 241.0.59.254241.0.59.255510
31241.0.60.0/23241.0.60.1 to 241.0.61.254241.0.61.255510
32241.0.62.0/23241.0.62.1 to 241.0.63.254241.0.63.255510
33241.0.64.0/23241.0.64.1 to 241.0.65.254241.0.65.255510
34241.0.66.0/23241.0.66.1 to 241.0.67.254241.0.67.255510
35241.0.68.0/23241.0.68.1 to 241.0.69.254241.0.69.255510
36241.0.70.0/23241.0.70.1 to 241.0.71.254241.0.71.255510
37241.0.72.0/23241.0.72.1 to 241.0.73.254241.0.73.255510
38241.0.74.0/23241.0.74.1 to 241.0.75.254241.0.75.255510
39241.0.76.0/23241.0.76.1 to 241.0.77.254241.0.77.255510
40241.0.78.0/23241.0.78.1 to 241.0.79.254241.0.79.255510
41241.0.80.0/23241.0.80.1 to 241.0.81.254241.0.81.255510
42241.0.82.0/23241.0.82.1 to 241.0.83.254241.0.83.255510
43241.0.84.0/23241.0.84.1 to 241.0.85.254241.0.85.255510
44241.0.86.0/23241.0.86.1 to 241.0.87.254241.0.87.255510
45241.0.88.0/23241.0.88.1 to 241.0.89.254241.0.89.255510
46241.0.90.0/23241.0.90.1 to 241.0.91.254241.0.91.255510
47241.0.92.0/23241.0.92.1 to 241.0.93.254241.0.93.255510
48241.0.94.0/23241.0.94.1 to 241.0.95.254241.0.95.255510
49241.0.96.0/23241.0.96.1 to 241.0.97.254241.0.97.255510
50241.0.98.0/23241.0.98.1 to 241.0.99.254241.0.99.255510
51241.0.100.0/23241.0.100.1 to 241.0.101.254241.0.101.255510
52241.0.102.0/23241.0.102.1 to 241.0.103.254241.0.103.255510
53241.0.104.0/23241.0.104.1 to 241.0.105.254241.0.105.255510
54241.0.106.0/23241.0.106.1 to 241.0.107.254241.0.107.255510
55241.0.108.0/23241.0.108.1 to 241.0.109.254241.0.109.255510
56241.0.110.0/23241.0.110.1 to 241.0.111.254241.0.111.255510
57241.0.112.0/23241.0.112.1 to 241.0.113.254241.0.113.255510
58241.0.114.0/23241.0.114.1 to 241.0.115.254241.0.115.255510
59241.0.116.0/23241.0.116.1 to 241.0.117.254241.0.117.255510
60241.0.118.0/23241.0.118.1 to 241.0.119.254241.0.119.255510
61241.0.120.0/23241.0.120.1 to 241.0.121.254241.0.121.255510
62241.0.122.0/23241.0.122.1 to 241.0.123.254241.0.123.255510
63241.0.124.0/23241.0.124.1 to 241.0.125.254241.0.125.255510
64241.0.126.0/23241.0.126.1 to 241.0.127.254241.0.127.255510
65241.0.128.0/23241.0.128.1 to 241.0.129.254241.0.129.255510
66241.0.130.0/23241.0.130.1 to 241.0.131.254241.0.131.255510
67241.0.132.0/23241.0.132.1 to 241.0.133.254241.0.133.255510
68241.0.134.0/23241.0.134.1 to 241.0.135.254241.0.135.255510
69241.0.136.0/23241.0.136.1 to 241.0.137.254241.0.137.255510
70241.0.138.0/23241.0.138.1 to 241.0.139.254241.0.139.255510
71241.0.140.0/23241.0.140.1 to 241.0.141.254241.0.141.255510
72241.0.142.0/23241.0.142.1 to 241.0.143.254241.0.143.255510
73241.0.144.0/23241.0.144.1 to 241.0.145.254241.0.145.255510
74241.0.146.0/23241.0.146.1 to 241.0.147.254241.0.147.255510
75241.0.148.0/23241.0.148.1 to 241.0.149.254241.0.149.255510
76241.0.150.0/23241.0.150.1 to 241.0.151.254241.0.151.255510
77241.0.152.0/23241.0.152.1 to 241.0.153.254241.0.153.255510
78241.0.154.0/23241.0.154.1 to 241.0.155.254241.0.155.255510
79241.0.156.0/23241.0.156.1 to 241.0.157.254241.0.157.255510
80241.0.158.0/23241.0.158.1 to 241.0.159.254241.0.159.255510
81241.0.160.0/23241.0.160.1 to 241.0.161.254241.0.161.255510
82241.0.162.0/23241.0.162.1 to 241.0.163.254241.0.163.255510
83241.0.164.0/23241.0.164.1 to 241.0.165.254241.0.165.255510
84241.0.166.0/23241.0.166.1 to 241.0.167.254241.0.167.255510
85241.0.168.0/23241.0.168.1 to 241.0.169.254241.0.169.255510
86241.0.170.0/23241.0.170.1 to 241.0.171.254241.0.171.255510
87241.0.172.0/23241.0.172.1 to 241.0.173.254241.0.173.255510
88241.0.174.0/23241.0.174.1 to 241.0.175.254241.0.175.255510
89241.0.176.0/23241.0.176.1 to 241.0.177.254241.0.177.255510
90241.0.178.0/23241.0.178.1 to 241.0.179.254241.0.179.255510
91241.0.180.0/23241.0.180.1 to 241.0.181.254241.0.181.255510
92241.0.182.0/23241.0.182.1 to 241.0.183.254241.0.183.255510
93241.0.184.0/23241.0.184.1 to 241.0.185.254241.0.185.255510
94241.0.186.0/23241.0.186.1 to 241.0.187.254241.0.187.255510
95241.0.188.0/23241.0.188.1 to 241.0.189.254241.0.189.255510
96241.0.190.0/23241.0.190.1 to 241.0.191.254241.0.191.255510
97241.0.192.0/23241.0.192.1 to 241.0.193.254241.0.193.255510
98241.0.194.0/23241.0.194.1 to 241.0.195.254241.0.195.255510
99241.0.196.0/23241.0.196.1 to 241.0.197.254241.0.197.255510
100241.0.198.0/23241.0.198.1 to 241.0.199.254241.0.199.255510
101241.0.200.0/23241.0.200.1 to 241.0.201.254241.0.201.255510
102241.0.202.0/23241.0.202.1 to 241.0.203.254241.0.203.255510
103241.0.204.0/23241.0.204.1 to 241.0.205.254241.0.205.255510
104241.0.206.0/23241.0.206.1 to 241.0.207.254241.0.207.255510
105241.0.208.0/23241.0.208.1 to 241.0.209.254241.0.209.255510
106241.0.210.0/23241.0.210.1 to 241.0.211.254241.0.211.255510
107241.0.212.0/23241.0.212.1 to 241.0.213.254241.0.213.255510
108241.0.214.0/23241.0.214.1 to 241.0.215.254241.0.215.255510
109241.0.216.0/23241.0.216.1 to 241.0.217.254241.0.217.255510
110241.0.218.0/23241.0.218.1 to 241.0.219.254241.0.219.255510
111241.0.220.0/23241.0.220.1 to 241.0.221.254241.0.221.255510
112241.0.222.0/23241.0.222.1 to 241.0.223.254241.0.223.255510
113241.0.224.0/23241.0.224.1 to 241.0.225.254241.0.225.255510
114241.0.226.0/23241.0.226.1 to 241.0.227.254241.0.227.255510
115241.0.228.0/23241.0.228.1 to 241.0.229.254241.0.229.255510
116241.0.230.0/23241.0.230.1 to 241.0.231.254241.0.231.255510
117241.0.232.0/23241.0.232.1 to 241.0.233.254241.0.233.255510
118241.0.234.0/23241.0.234.1 to 241.0.235.254241.0.235.255510
119241.0.236.0/23241.0.236.1 to 241.0.237.254241.0.237.255510
120241.0.238.0/23241.0.238.1 to 241.0.239.254241.0.239.255510
121241.0.240.0/23241.0.240.1 to 241.0.241.254241.0.241.255510
122241.0.242.0/23241.0.242.1 to 241.0.243.254241.0.243.255510
123241.0.244.0/23241.0.244.1 to 241.0.245.254241.0.245.255510
124241.0.246.0/23241.0.246.1 to 241.0.247.254241.0.247.255510
125241.0.248.0/23241.0.248.1 to 241.0.249.254241.0.249.255510
126241.0.250.0/23241.0.250.1 to 241.0.251.254241.0.251.255510
127241.0.252.0/23241.0.252.1 to 241.0.253.254241.0.253.255510
128241.0.254.0/23241.0.254.1 to 241.0.255.254241.0.255.255510
129241.1.0.0/23241.1.0.1 to 241.1.1.254241.1.1.255510
130241.1.2.0/23241.1.2.1 to 241.1.3.254241.1.3.255510
131241.1.4.0/23241.1.4.1 to 241.1.5.254241.1.5.255510
132241.1.6.0/23241.1.6.1 to 241.1.7.254241.1.7.255510
133241.1.8.0/23241.1.8.1 to 241.1.9.254241.1.9.255510
134241.1.10.0/23241.1.10.1 to 241.1.11.254241.1.11.255510
135241.1.12.0/23241.1.12.1 to 241.1.13.254241.1.13.255510
136241.1.14.0/23241.1.14.1 to 241.1.15.254241.1.15.255510
137241.1.16.0/23241.1.16.1 to 241.1.17.254241.1.17.255510
138241.1.18.0/23241.1.18.1 to 241.1.19.254241.1.19.255510
139241.1.20.0/23241.1.20.1 to 241.1.21.254241.1.21.255510
140241.1.22.0/23241.1.22.1 to 241.1.23.254241.1.23.255510
141241.1.24.0/23241.1.24.1 to 241.1.25.254241.1.25.255510
142241.1.26.0/23241.1.26.1 to 241.1.27.254241.1.27.255510
143241.1.28.0/23241.1.28.1 to 241.1.29.254241.1.29.255510
144241.1.30.0/23241.1.30.1 to 241.1.31.254241.1.31.255510
145241.1.32.0/23241.1.32.1 to 241.1.33.254241.1.33.255510
146241.1.34.0/23241.1.34.1 to 241.1.35.254241.1.35.255510
147241.1.36.0/23241.1.36.1 to 241.1.37.254241.1.37.255510
148241.1.38.0/23241.1.38.1 to 241.1.39.254241.1.39.255510
149241.1.40.0/23241.1.40.1 to 241.1.41.254241.1.41.255510
150241.1.42.0/23241.1.42.1 to 241.1.43.254241.1.43.255510
151241.1.44.0/23241.1.44.1 to 241.1.45.254241.1.45.255510
152241.1.46.0/23241.1.46.1 to 241.1.47.254241.1.47.255510
153241.1.48.0/23241.1.48.1 to 241.1.49.254241.1.49.255510
154241.1.50.0/23241.1.50.1 to 241.1.51.254241.1.51.255510
155241.1.52.0/23241.1.52.1 to 241.1.53.254241.1.53.255510
156241.1.54.0/23241.1.54.1 to 241.1.55.254241.1.55.255510
157241.1.56.0/23241.1.56.1 to 241.1.57.254241.1.57.255510
158241.1.58.0/23241.1.58.1 to 241.1.59.254241.1.59.255510
159241.1.60.0/23241.1.60.1 to 241.1.61.254241.1.61.255510
160241.1.62.0/23241.1.62.1 to 241.1.63.254241.1.63.255510
161241.1.64.0/23241.1.64.1 to 241.1.65.254241.1.65.255510
162241.1.66.0/23241.1.66.1 to 241.1.67.254241.1.67.255510
163241.1.68.0/23241.1.68.1 to 241.1.69.254241.1.69.255510
164241.1.70.0/23241.1.70.1 to 241.1.71.254241.1.71.255510
165241.1.72.0/23241.1.72.1 to 241.1.73.254241.1.73.255510
166241.1.74.0/23241.1.74.1 to 241.1.75.254241.1.75.255510
167241.1.76.0/23241.1.76.1 to 241.1.77.254241.1.77.255510
168241.1.78.0/23241.1.78.1 to 241.1.79.254241.1.79.255510
169241.1.80.0/23241.1.80.1 to 241.1.81.254241.1.81.255510
170241.1.82.0/23241.1.82.1 to 241.1.83.254241.1.83.255510
171241.1.84.0/23241.1.84.1 to 241.1.85.254241.1.85.255510
172241.1.86.0/23241.1.86.1 to 241.1.87.254241.1.87.255510
173241.1.88.0/23241.1.88.1 to 241.1.89.254241.1.89.255510
174241.1.90.0/23241.1.90.1 to 241.1.91.254241.1.91.255510
175241.1.92.0/23241.1.92.1 to 241.1.93.254241.1.93.255510
176241.1.94.0/23241.1.94.1 to 241.1.95.254241.1.95.255510
177241.1.96.0/23241.1.96.1 to 241.1.97.254241.1.97.255510
178241.1.98.0/23241.1.98.1 to 241.1.99.254241.1.99.255510
179241.1.100.0/23241.1.100.1 to 241.1.101.254241.1.101.255510
180241.1.102.0/23241.1.102.1 to 241.1.103.254241.1.103.255510
181241.1.104.0/23241.1.104.1 to 241.1.105.254241.1.105.255510
182241.1.106.0/23241.1.106.1 to 241.1.107.254241.1.107.255510
183241.1.108.0/23241.1.108.1 to 241.1.109.254241.1.109.255510
184241.1.110.0/23241.1.110.1 to 241.1.111.254241.1.111.255510
185241.1.112.0/23241.1.112.1 to 241.1.113.254241.1.113.255510
186241.1.114.0/23241.1.114.1 to 241.1.115.254241.1.115.255510
187241.1.116.0/23241.1.116.1 to 241.1.117.254241.1.117.255510
188241.1.118.0/23241.1.118.1 to 241.1.119.254241.1.119.255510
189241.1.120.0/23241.1.120.1 to 241.1.121.254241.1.121.255510
190241.1.122.0/23241.1.122.1 to 241.1.123.254241.1.123.255510
191241.1.124.0/23241.1.124.1 to 241.1.125.254241.1.125.255510
192241.1.126.0/23241.1.126.1 to 241.1.127.254241.1.127.255510
193241.1.128.0/23241.1.128.1 to 241.1.129.254241.1.129.255510
194241.1.130.0/23241.1.130.1 to 241.1.131.254241.1.131.255510
195241.1.132.0/23241.1.132.1 to 241.1.133.254241.1.133.255510
196241.1.134.0/23241.1.134.1 to 241.1.135.254241.1.135.255510
197241.1.136.0/23241.1.136.1 to 241.1.137.254241.1.137.255510
198241.1.138.0/23241.1.138.1 to 241.1.139.254241.1.139.255510
199241.1.140.0/23241.1.140.1 to 241.1.141.254241.1.141.255510
200241.1.142.0/23241.1.142.1 to 241.1.143.254241.1.143.255510
201241.1.144.0/23241.1.144.1 to 241.1.145.254241.1.145.255510
202241.1.146.0/23241.1.146.1 to 241.1.147.254241.1.147.255510
203241.1.148.0/23241.1.148.1 to 241.1.149.254241.1.149.255510
204241.1.150.0/23241.1.150.1 to 241.1.151.254241.1.151.255510
205241.1.152.0/23241.1.152.1 to 241.1.153.254241.1.153.255510
206241.1.154.0/23241.1.154.1 to 241.1.155.254241.1.155.255510
207241.1.156.0/23241.1.156.1 to 241.1.157.254241.1.157.255510
208241.1.158.0/23241.1.158.1 to 241.1.159.254241.1.159.255510
209241.1.160.0/23241.1.160.1 to 241.1.161.254241.1.161.255510
210241.1.162.0/23241.1.162.1 to 241.1.163.254241.1.163.255510
211241.1.164.0/23241.1.164.1 to 241.1.165.254241.1.165.255510
212241.1.166.0/23241.1.166.1 to 241.1.167.254241.1.167.255510
213241.1.168.0/23241.1.168.1 to 241.1.169.254241.1.169.255510
214241.1.170.0/23241.1.170.1 to 241.1.171.254241.1.171.255510
215241.1.172.0/23241.1.172.1 to 241.1.173.254241.1.173.255510
216241.1.174.0/23241.1.174.1 to 241.1.175.254241.1.175.255510
217241.1.176.0/23241.1.176.1 to 241.1.177.254241.1.177.255510
218241.1.178.0/23241.1.178.1 to 241.1.179.254241.1.179.255510
219241.1.180.0/23241.1.180.1 to 241.1.181.254241.1.181.255510
220241.1.182.0/23241.1.182.1 to 241.1.183.254241.1.183.255510
221241.1.184.0/23241.1.184.1 to 241.1.185.254241.1.185.255510
222241.1.186.0/23241.1.186.1 to 241.1.187.254241.1.187.255510
223241.1.188.0/23241.1.188.1 to 241.1.189.254241.1.189.255510
224241.1.190.0/23241.1.190.1 to 241.1.191.254241.1.191.255510
225241.1.192.0/23241.1.192.1 to 241.1.193.254241.1.193.255510
226241.1.194.0/23241.1.194.1 to 241.1.195.254241.1.195.255510
227241.1.196.0/23241.1.196.1 to 241.1.197.254241.1.197.255510
228241.1.198.0/23241.1.198.1 to 241.1.199.254241.1.199.255510
229241.1.200.0/23241.1.200.1 to 241.1.201.254241.1.201.255510
230241.1.202.0/23241.1.202.1 to 241.1.203.254241.1.203.255510
231241.1.204.0/23241.1.204.1 to 241.1.205.254241.1.205.255510
232241.1.206.0/23241.1.206.1 to 241.1.207.254241.1.207.255510
233241.1.208.0/23241.1.208.1 to 241.1.209.254241.1.209.255510
234241.1.210.0/23241.1.210.1 to 241.1.211.254241.1.211.255510
235241.1.212.0/23241.1.212.1 to 241.1.213.254241.1.213.255510
236241.1.214.0/23241.1.214.1 to 241.1.215.254241.1.215.255510
237241.1.216.0/23241.1.216.1 to 241.1.217.254241.1.217.255510
238241.1.218.0/23241.1.218.1 to 241.1.219.254241.1.219.255510
239241.1.220.0/23241.1.220.1 to 241.1.221.254241.1.221.255510
240241.1.222.0/23241.1.222.1 to 241.1.223.254241.1.223.255510
241241.1.224.0/23241.1.224.1 to 241.1.225.254241.1.225.255510
242241.1.226.0/23241.1.226.1 to 241.1.227.254241.1.227.255510
243241.1.228.0/23241.1.228.1 to 241.1.229.254241.1.229.255510
244241.1.230.0/23241.1.230.1 to 241.1.231.254241.1.231.255510
245241.1.232.0/23241.1.232.1 to 241.1.233.254241.1.233.255510
246241.1.234.0/23241.1.234.1 to 241.1.235.254241.1.235.255510
247241.1.236.0/23241.1.236.1 to 241.1.237.254241.1.237.255510
248241.1.238.0/23241.1.238.1 to 241.1.239.254241.1.239.255510
249241.1.240.0/23241.1.240.1 to 241.1.241.254241.1.241.255510
250241.1.242.0/23241.1.242.1 to 241.1.243.254241.1.243.255510
251241.1.244.0/23241.1.244.1 to 241.1.245.254241.1.245.255510
252241.1.246.0/23241.1.246.1 to 241.1.247.254241.1.247.255510
253241.1.248.0/23241.1.248.1 to 241.1.249.254241.1.249.255510
254241.1.250.0/23241.1.250.1 to 241.1.251.254241.1.251.255510
255241.1.252.0/23241.1.252.1 to 241.1.253.254241.1.253.255510
256241.1.254.0/23241.1.254.1 to 241.1.255.254241.1.255.255510

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.