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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.

Network244.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
244.0.0.0
Broadcast address
247.255.255.255
First usable
244.0.0.1
Last usable
247.255.255.254
Usable hosts
67,108,862 (67,108,864 less the network and broadcast addresses)
Subnet mask
252.0.0.0
Wildcard mask
3.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/6
Type
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex F4000000 · Integer 4093640704 to 4160749567
Reverse DNS zones
244.in-addr.arpa
245.in-addr.arpa
246.in-addr.arpa
247.in-addr.arpa
/6 is not on a 8-bit boundary, so it takes 4 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11110100.00000000.00000000.00000000244.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network11110100.00000000.00000000.00000000244.0.0.0
Broadcast11110111.11111111.11111111.11111111247.255.255.255
Split into smaller subnets/16
/7 (2)/8 (4)/9 (8)/10 (16)/11 (32)/12 (64)/13 (128)/14 (256)/15 (512)/16 (1,024)/17 (2,048)/18 (4,096)

244.0.0.0/6 makes 1,024 subnets of /16; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1244.0.0.0/16244.0.0.1 to 244.0.255.254244.0.255.25565,534
2244.1.0.0/16244.1.0.1 to 244.1.255.254244.1.255.25565,534
3244.2.0.0/16244.2.0.1 to 244.2.255.254244.2.255.25565,534
4244.3.0.0/16244.3.0.1 to 244.3.255.254244.3.255.25565,534
5244.4.0.0/16244.4.0.1 to 244.4.255.254244.4.255.25565,534
6244.5.0.0/16244.5.0.1 to 244.5.255.254244.5.255.25565,534
7244.6.0.0/16244.6.0.1 to 244.6.255.254244.6.255.25565,534
8244.7.0.0/16244.7.0.1 to 244.7.255.254244.7.255.25565,534
9244.8.0.0/16244.8.0.1 to 244.8.255.254244.8.255.25565,534
10244.9.0.0/16244.9.0.1 to 244.9.255.254244.9.255.25565,534
11244.10.0.0/16244.10.0.1 to 244.10.255.254244.10.255.25565,534
12244.11.0.0/16244.11.0.1 to 244.11.255.254244.11.255.25565,534
13244.12.0.0/16244.12.0.1 to 244.12.255.254244.12.255.25565,534
14244.13.0.0/16244.13.0.1 to 244.13.255.254244.13.255.25565,534
15244.14.0.0/16244.14.0.1 to 244.14.255.254244.14.255.25565,534
16244.15.0.0/16244.15.0.1 to 244.15.255.254244.15.255.25565,534
17244.16.0.0/16244.16.0.1 to 244.16.255.254244.16.255.25565,534
18244.17.0.0/16244.17.0.1 to 244.17.255.254244.17.255.25565,534
19244.18.0.0/16244.18.0.1 to 244.18.255.254244.18.255.25565,534
20244.19.0.0/16244.19.0.1 to 244.19.255.254244.19.255.25565,534
21244.20.0.0/16244.20.0.1 to 244.20.255.254244.20.255.25565,534
22244.21.0.0/16244.21.0.1 to 244.21.255.254244.21.255.25565,534
23244.22.0.0/16244.22.0.1 to 244.22.255.254244.22.255.25565,534
24244.23.0.0/16244.23.0.1 to 244.23.255.254244.23.255.25565,534
25244.24.0.0/16244.24.0.1 to 244.24.255.254244.24.255.25565,534
26244.25.0.0/16244.25.0.1 to 244.25.255.254244.25.255.25565,534
27244.26.0.0/16244.26.0.1 to 244.26.255.254244.26.255.25565,534
28244.27.0.0/16244.27.0.1 to 244.27.255.254244.27.255.25565,534
29244.28.0.0/16244.28.0.1 to 244.28.255.254244.28.255.25565,534
30244.29.0.0/16244.29.0.1 to 244.29.255.254244.29.255.25565,534
31244.30.0.0/16244.30.0.1 to 244.30.255.254244.30.255.25565,534
32244.31.0.0/16244.31.0.1 to 244.31.255.254244.31.255.25565,534
33244.32.0.0/16244.32.0.1 to 244.32.255.254244.32.255.25565,534
34244.33.0.0/16244.33.0.1 to 244.33.255.254244.33.255.25565,534
35244.34.0.0/16244.34.0.1 to 244.34.255.254244.34.255.25565,534
36244.35.0.0/16244.35.0.1 to 244.35.255.254244.35.255.25565,534
37244.36.0.0/16244.36.0.1 to 244.36.255.254244.36.255.25565,534
38244.37.0.0/16244.37.0.1 to 244.37.255.254244.37.255.25565,534
39244.38.0.0/16244.38.0.1 to 244.38.255.254244.38.255.25565,534
40244.39.0.0/16244.39.0.1 to 244.39.255.254244.39.255.25565,534
41244.40.0.0/16244.40.0.1 to 244.40.255.254244.40.255.25565,534
42244.41.0.0/16244.41.0.1 to 244.41.255.254244.41.255.25565,534
43244.42.0.0/16244.42.0.1 to 244.42.255.254244.42.255.25565,534
44244.43.0.0/16244.43.0.1 to 244.43.255.254244.43.255.25565,534
45244.44.0.0/16244.44.0.1 to 244.44.255.254244.44.255.25565,534
46244.45.0.0/16244.45.0.1 to 244.45.255.254244.45.255.25565,534
47244.46.0.0/16244.46.0.1 to 244.46.255.254244.46.255.25565,534
48244.47.0.0/16244.47.0.1 to 244.47.255.254244.47.255.25565,534
49244.48.0.0/16244.48.0.1 to 244.48.255.254244.48.255.25565,534
50244.49.0.0/16244.49.0.1 to 244.49.255.254244.49.255.25565,534
51244.50.0.0/16244.50.0.1 to 244.50.255.254244.50.255.25565,534
52244.51.0.0/16244.51.0.1 to 244.51.255.254244.51.255.25565,534
53244.52.0.0/16244.52.0.1 to 244.52.255.254244.52.255.25565,534
54244.53.0.0/16244.53.0.1 to 244.53.255.254244.53.255.25565,534
55244.54.0.0/16244.54.0.1 to 244.54.255.254244.54.255.25565,534
56244.55.0.0/16244.55.0.1 to 244.55.255.254244.55.255.25565,534
57244.56.0.0/16244.56.0.1 to 244.56.255.254244.56.255.25565,534
58244.57.0.0/16244.57.0.1 to 244.57.255.254244.57.255.25565,534
59244.58.0.0/16244.58.0.1 to 244.58.255.254244.58.255.25565,534
60244.59.0.0/16244.59.0.1 to 244.59.255.254244.59.255.25565,534
61244.60.0.0/16244.60.0.1 to 244.60.255.254244.60.255.25565,534
62244.61.0.0/16244.61.0.1 to 244.61.255.254244.61.255.25565,534
63244.62.0.0/16244.62.0.1 to 244.62.255.254244.62.255.25565,534
64244.63.0.0/16244.63.0.1 to 244.63.255.254244.63.255.25565,534
65244.64.0.0/16244.64.0.1 to 244.64.255.254244.64.255.25565,534
66244.65.0.0/16244.65.0.1 to 244.65.255.254244.65.255.25565,534
67244.66.0.0/16244.66.0.1 to 244.66.255.254244.66.255.25565,534
68244.67.0.0/16244.67.0.1 to 244.67.255.254244.67.255.25565,534
69244.68.0.0/16244.68.0.1 to 244.68.255.254244.68.255.25565,534
70244.69.0.0/16244.69.0.1 to 244.69.255.254244.69.255.25565,534
71244.70.0.0/16244.70.0.1 to 244.70.255.254244.70.255.25565,534
72244.71.0.0/16244.71.0.1 to 244.71.255.254244.71.255.25565,534
73244.72.0.0/16244.72.0.1 to 244.72.255.254244.72.255.25565,534
74244.73.0.0/16244.73.0.1 to 244.73.255.254244.73.255.25565,534
75244.74.0.0/16244.74.0.1 to 244.74.255.254244.74.255.25565,534
76244.75.0.0/16244.75.0.1 to 244.75.255.254244.75.255.25565,534
77244.76.0.0/16244.76.0.1 to 244.76.255.254244.76.255.25565,534
78244.77.0.0/16244.77.0.1 to 244.77.255.254244.77.255.25565,534
79244.78.0.0/16244.78.0.1 to 244.78.255.254244.78.255.25565,534
80244.79.0.0/16244.79.0.1 to 244.79.255.254244.79.255.25565,534
81244.80.0.0/16244.80.0.1 to 244.80.255.254244.80.255.25565,534
82244.81.0.0/16244.81.0.1 to 244.81.255.254244.81.255.25565,534
83244.82.0.0/16244.82.0.1 to 244.82.255.254244.82.255.25565,534
84244.83.0.0/16244.83.0.1 to 244.83.255.254244.83.255.25565,534
85244.84.0.0/16244.84.0.1 to 244.84.255.254244.84.255.25565,534
86244.85.0.0/16244.85.0.1 to 244.85.255.254244.85.255.25565,534
87244.86.0.0/16244.86.0.1 to 244.86.255.254244.86.255.25565,534
88244.87.0.0/16244.87.0.1 to 244.87.255.254244.87.255.25565,534
89244.88.0.0/16244.88.0.1 to 244.88.255.254244.88.255.25565,534
90244.89.0.0/16244.89.0.1 to 244.89.255.254244.89.255.25565,534
91244.90.0.0/16244.90.0.1 to 244.90.255.254244.90.255.25565,534
92244.91.0.0/16244.91.0.1 to 244.91.255.254244.91.255.25565,534
93244.92.0.0/16244.92.0.1 to 244.92.255.254244.92.255.25565,534
94244.93.0.0/16244.93.0.1 to 244.93.255.254244.93.255.25565,534
95244.94.0.0/16244.94.0.1 to 244.94.255.254244.94.255.25565,534
96244.95.0.0/16244.95.0.1 to 244.95.255.254244.95.255.25565,534
97244.96.0.0/16244.96.0.1 to 244.96.255.254244.96.255.25565,534
98244.97.0.0/16244.97.0.1 to 244.97.255.254244.97.255.25565,534
99244.98.0.0/16244.98.0.1 to 244.98.255.254244.98.255.25565,534
100244.99.0.0/16244.99.0.1 to 244.99.255.254244.99.255.25565,534
101244.100.0.0/16244.100.0.1 to 244.100.255.254244.100.255.25565,534
102244.101.0.0/16244.101.0.1 to 244.101.255.254244.101.255.25565,534
103244.102.0.0/16244.102.0.1 to 244.102.255.254244.102.255.25565,534
104244.103.0.0/16244.103.0.1 to 244.103.255.254244.103.255.25565,534
105244.104.0.0/16244.104.0.1 to 244.104.255.254244.104.255.25565,534
106244.105.0.0/16244.105.0.1 to 244.105.255.254244.105.255.25565,534
107244.106.0.0/16244.106.0.1 to 244.106.255.254244.106.255.25565,534
108244.107.0.0/16244.107.0.1 to 244.107.255.254244.107.255.25565,534
109244.108.0.0/16244.108.0.1 to 244.108.255.254244.108.255.25565,534
110244.109.0.0/16244.109.0.1 to 244.109.255.254244.109.255.25565,534
111244.110.0.0/16244.110.0.1 to 244.110.255.254244.110.255.25565,534
112244.111.0.0/16244.111.0.1 to 244.111.255.254244.111.255.25565,534
113244.112.0.0/16244.112.0.1 to 244.112.255.254244.112.255.25565,534
114244.113.0.0/16244.113.0.1 to 244.113.255.254244.113.255.25565,534
115244.114.0.0/16244.114.0.1 to 244.114.255.254244.114.255.25565,534
116244.115.0.0/16244.115.0.1 to 244.115.255.254244.115.255.25565,534
117244.116.0.0/16244.116.0.1 to 244.116.255.254244.116.255.25565,534
118244.117.0.0/16244.117.0.1 to 244.117.255.254244.117.255.25565,534
119244.118.0.0/16244.118.0.1 to 244.118.255.254244.118.255.25565,534
120244.119.0.0/16244.119.0.1 to 244.119.255.254244.119.255.25565,534
121244.120.0.0/16244.120.0.1 to 244.120.255.254244.120.255.25565,534
122244.121.0.0/16244.121.0.1 to 244.121.255.254244.121.255.25565,534
123244.122.0.0/16244.122.0.1 to 244.122.255.254244.122.255.25565,534
124244.123.0.0/16244.123.0.1 to 244.123.255.254244.123.255.25565,534
125244.124.0.0/16244.124.0.1 to 244.124.255.254244.124.255.25565,534
126244.125.0.0/16244.125.0.1 to 244.125.255.254244.125.255.25565,534
127244.126.0.0/16244.126.0.1 to 244.126.255.254244.126.255.25565,534
128244.127.0.0/16244.127.0.1 to 244.127.255.254244.127.255.25565,534
129244.128.0.0/16244.128.0.1 to 244.128.255.254244.128.255.25565,534
130244.129.0.0/16244.129.0.1 to 244.129.255.254244.129.255.25565,534
131244.130.0.0/16244.130.0.1 to 244.130.255.254244.130.255.25565,534
132244.131.0.0/16244.131.0.1 to 244.131.255.254244.131.255.25565,534
133244.132.0.0/16244.132.0.1 to 244.132.255.254244.132.255.25565,534
134244.133.0.0/16244.133.0.1 to 244.133.255.254244.133.255.25565,534
135244.134.0.0/16244.134.0.1 to 244.134.255.254244.134.255.25565,534
136244.135.0.0/16244.135.0.1 to 244.135.255.254244.135.255.25565,534
137244.136.0.0/16244.136.0.1 to 244.136.255.254244.136.255.25565,534
138244.137.0.0/16244.137.0.1 to 244.137.255.254244.137.255.25565,534
139244.138.0.0/16244.138.0.1 to 244.138.255.254244.138.255.25565,534
140244.139.0.0/16244.139.0.1 to 244.139.255.254244.139.255.25565,534
141244.140.0.0/16244.140.0.1 to 244.140.255.254244.140.255.25565,534
142244.141.0.0/16244.141.0.1 to 244.141.255.254244.141.255.25565,534
143244.142.0.0/16244.142.0.1 to 244.142.255.254244.142.255.25565,534
144244.143.0.0/16244.143.0.1 to 244.143.255.254244.143.255.25565,534
145244.144.0.0/16244.144.0.1 to 244.144.255.254244.144.255.25565,534
146244.145.0.0/16244.145.0.1 to 244.145.255.254244.145.255.25565,534
147244.146.0.0/16244.146.0.1 to 244.146.255.254244.146.255.25565,534
148244.147.0.0/16244.147.0.1 to 244.147.255.254244.147.255.25565,534
149244.148.0.0/16244.148.0.1 to 244.148.255.254244.148.255.25565,534
150244.149.0.0/16244.149.0.1 to 244.149.255.254244.149.255.25565,534
151244.150.0.0/16244.150.0.1 to 244.150.255.254244.150.255.25565,534
152244.151.0.0/16244.151.0.1 to 244.151.255.254244.151.255.25565,534
153244.152.0.0/16244.152.0.1 to 244.152.255.254244.152.255.25565,534
154244.153.0.0/16244.153.0.1 to 244.153.255.254244.153.255.25565,534
155244.154.0.0/16244.154.0.1 to 244.154.255.254244.154.255.25565,534
156244.155.0.0/16244.155.0.1 to 244.155.255.254244.155.255.25565,534
157244.156.0.0/16244.156.0.1 to 244.156.255.254244.156.255.25565,534
158244.157.0.0/16244.157.0.1 to 244.157.255.254244.157.255.25565,534
159244.158.0.0/16244.158.0.1 to 244.158.255.254244.158.255.25565,534
160244.159.0.0/16244.159.0.1 to 244.159.255.254244.159.255.25565,534
161244.160.0.0/16244.160.0.1 to 244.160.255.254244.160.255.25565,534
162244.161.0.0/16244.161.0.1 to 244.161.255.254244.161.255.25565,534
163244.162.0.0/16244.162.0.1 to 244.162.255.254244.162.255.25565,534
164244.163.0.0/16244.163.0.1 to 244.163.255.254244.163.255.25565,534
165244.164.0.0/16244.164.0.1 to 244.164.255.254244.164.255.25565,534
166244.165.0.0/16244.165.0.1 to 244.165.255.254244.165.255.25565,534
167244.166.0.0/16244.166.0.1 to 244.166.255.254244.166.255.25565,534
168244.167.0.0/16244.167.0.1 to 244.167.255.254244.167.255.25565,534
169244.168.0.0/16244.168.0.1 to 244.168.255.254244.168.255.25565,534
170244.169.0.0/16244.169.0.1 to 244.169.255.254244.169.255.25565,534
171244.170.0.0/16244.170.0.1 to 244.170.255.254244.170.255.25565,534
172244.171.0.0/16244.171.0.1 to 244.171.255.254244.171.255.25565,534
173244.172.0.0/16244.172.0.1 to 244.172.255.254244.172.255.25565,534
174244.173.0.0/16244.173.0.1 to 244.173.255.254244.173.255.25565,534
175244.174.0.0/16244.174.0.1 to 244.174.255.254244.174.255.25565,534
176244.175.0.0/16244.175.0.1 to 244.175.255.254244.175.255.25565,534
177244.176.0.0/16244.176.0.1 to 244.176.255.254244.176.255.25565,534
178244.177.0.0/16244.177.0.1 to 244.177.255.254244.177.255.25565,534
179244.178.0.0/16244.178.0.1 to 244.178.255.254244.178.255.25565,534
180244.179.0.0/16244.179.0.1 to 244.179.255.254244.179.255.25565,534
181244.180.0.0/16244.180.0.1 to 244.180.255.254244.180.255.25565,534
182244.181.0.0/16244.181.0.1 to 244.181.255.254244.181.255.25565,534
183244.182.0.0/16244.182.0.1 to 244.182.255.254244.182.255.25565,534
184244.183.0.0/16244.183.0.1 to 244.183.255.254244.183.255.25565,534
185244.184.0.0/16244.184.0.1 to 244.184.255.254244.184.255.25565,534
186244.185.0.0/16244.185.0.1 to 244.185.255.254244.185.255.25565,534
187244.186.0.0/16244.186.0.1 to 244.186.255.254244.186.255.25565,534
188244.187.0.0/16244.187.0.1 to 244.187.255.254244.187.255.25565,534
189244.188.0.0/16244.188.0.1 to 244.188.255.254244.188.255.25565,534
190244.189.0.0/16244.189.0.1 to 244.189.255.254244.189.255.25565,534
191244.190.0.0/16244.190.0.1 to 244.190.255.254244.190.255.25565,534
192244.191.0.0/16244.191.0.1 to 244.191.255.254244.191.255.25565,534
193244.192.0.0/16244.192.0.1 to 244.192.255.254244.192.255.25565,534
194244.193.0.0/16244.193.0.1 to 244.193.255.254244.193.255.25565,534
195244.194.0.0/16244.194.0.1 to 244.194.255.254244.194.255.25565,534
196244.195.0.0/16244.195.0.1 to 244.195.255.254244.195.255.25565,534
197244.196.0.0/16244.196.0.1 to 244.196.255.254244.196.255.25565,534
198244.197.0.0/16244.197.0.1 to 244.197.255.254244.197.255.25565,534
199244.198.0.0/16244.198.0.1 to 244.198.255.254244.198.255.25565,534
200244.199.0.0/16244.199.0.1 to 244.199.255.254244.199.255.25565,534
201244.200.0.0/16244.200.0.1 to 244.200.255.254244.200.255.25565,534
202244.201.0.0/16244.201.0.1 to 244.201.255.254244.201.255.25565,534
203244.202.0.0/16244.202.0.1 to 244.202.255.254244.202.255.25565,534
204244.203.0.0/16244.203.0.1 to 244.203.255.254244.203.255.25565,534
205244.204.0.0/16244.204.0.1 to 244.204.255.254244.204.255.25565,534
206244.205.0.0/16244.205.0.1 to 244.205.255.254244.205.255.25565,534
207244.206.0.0/16244.206.0.1 to 244.206.255.254244.206.255.25565,534
208244.207.0.0/16244.207.0.1 to 244.207.255.254244.207.255.25565,534
209244.208.0.0/16244.208.0.1 to 244.208.255.254244.208.255.25565,534
210244.209.0.0/16244.209.0.1 to 244.209.255.254244.209.255.25565,534
211244.210.0.0/16244.210.0.1 to 244.210.255.254244.210.255.25565,534
212244.211.0.0/16244.211.0.1 to 244.211.255.254244.211.255.25565,534
213244.212.0.0/16244.212.0.1 to 244.212.255.254244.212.255.25565,534
214244.213.0.0/16244.213.0.1 to 244.213.255.254244.213.255.25565,534
215244.214.0.0/16244.214.0.1 to 244.214.255.254244.214.255.25565,534
216244.215.0.0/16244.215.0.1 to 244.215.255.254244.215.255.25565,534
217244.216.0.0/16244.216.0.1 to 244.216.255.254244.216.255.25565,534
218244.217.0.0/16244.217.0.1 to 244.217.255.254244.217.255.25565,534
219244.218.0.0/16244.218.0.1 to 244.218.255.254244.218.255.25565,534
220244.219.0.0/16244.219.0.1 to 244.219.255.254244.219.255.25565,534
221244.220.0.0/16244.220.0.1 to 244.220.255.254244.220.255.25565,534
222244.221.0.0/16244.221.0.1 to 244.221.255.254244.221.255.25565,534
223244.222.0.0/16244.222.0.1 to 244.222.255.254244.222.255.25565,534
224244.223.0.0/16244.223.0.1 to 244.223.255.254244.223.255.25565,534
225244.224.0.0/16244.224.0.1 to 244.224.255.254244.224.255.25565,534
226244.225.0.0/16244.225.0.1 to 244.225.255.254244.225.255.25565,534
227244.226.0.0/16244.226.0.1 to 244.226.255.254244.226.255.25565,534
228244.227.0.0/16244.227.0.1 to 244.227.255.254244.227.255.25565,534
229244.228.0.0/16244.228.0.1 to 244.228.255.254244.228.255.25565,534
230244.229.0.0/16244.229.0.1 to 244.229.255.254244.229.255.25565,534
231244.230.0.0/16244.230.0.1 to 244.230.255.254244.230.255.25565,534
232244.231.0.0/16244.231.0.1 to 244.231.255.254244.231.255.25565,534
233244.232.0.0/16244.232.0.1 to 244.232.255.254244.232.255.25565,534
234244.233.0.0/16244.233.0.1 to 244.233.255.254244.233.255.25565,534
235244.234.0.0/16244.234.0.1 to 244.234.255.254244.234.255.25565,534
236244.235.0.0/16244.235.0.1 to 244.235.255.254244.235.255.25565,534
237244.236.0.0/16244.236.0.1 to 244.236.255.254244.236.255.25565,534
238244.237.0.0/16244.237.0.1 to 244.237.255.254244.237.255.25565,534
239244.238.0.0/16244.238.0.1 to 244.238.255.254244.238.255.25565,534
240244.239.0.0/16244.239.0.1 to 244.239.255.254244.239.255.25565,534
241244.240.0.0/16244.240.0.1 to 244.240.255.254244.240.255.25565,534
242244.241.0.0/16244.241.0.1 to 244.241.255.254244.241.255.25565,534
243244.242.0.0/16244.242.0.1 to 244.242.255.254244.242.255.25565,534
244244.243.0.0/16244.243.0.1 to 244.243.255.254244.243.255.25565,534
245244.244.0.0/16244.244.0.1 to 244.244.255.254244.244.255.25565,534
246244.245.0.0/16244.245.0.1 to 244.245.255.254244.245.255.25565,534
247244.246.0.0/16244.246.0.1 to 244.246.255.254244.246.255.25565,534
248244.247.0.0/16244.247.0.1 to 244.247.255.254244.247.255.25565,534
249244.248.0.0/16244.248.0.1 to 244.248.255.254244.248.255.25565,534
250244.249.0.0/16244.249.0.1 to 244.249.255.254244.249.255.25565,534
251244.250.0.0/16244.250.0.1 to 244.250.255.254244.250.255.25565,534
252244.251.0.0/16244.251.0.1 to 244.251.255.254244.251.255.25565,534
253244.252.0.0/16244.252.0.1 to 244.252.255.254244.252.255.25565,534
254244.253.0.0/16244.253.0.1 to 244.253.255.254244.253.255.25565,534
255244.254.0.0/16244.254.0.1 to 244.254.255.254244.254.255.25565,534
256244.255.0.0/16244.255.0.1 to 244.255.255.254244.255.255.25565,534

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.