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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.

Network107.3.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
107.3.0.0
Broadcast address
107.3.255.255
First usable
107.3.0.1
Last usable
107.3.255.254
Usable hosts
65,534 (65,536 less the network and broadcast addresses)
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255 (Cisco ACLs, OSPF)
Prefix length
/16
Type
Public public
Old class
A (default /8)
As numbers
Hex 6B030000 · Integer 1795358720 to 1795424255
Reverse DNS zone
3.107.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01101011.00000011..00000000.00000000107.3.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network01101011.00000011..00000000.00000000107.3.0.0
Broadcast01101011.00000011..11111111.11111111107.3.255.255
Split into smaller subnets/24
/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

107.3.0.0/16 makes 256 subnets of /24.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1107.3.0.0/24107.3.0.1 to 107.3.0.254107.3.0.255254
2107.3.1.0/24107.3.1.1 to 107.3.1.254107.3.1.255254
3107.3.2.0/24107.3.2.1 to 107.3.2.254107.3.2.255254
4107.3.3.0/24107.3.3.1 to 107.3.3.254107.3.3.255254
5107.3.4.0/24107.3.4.1 to 107.3.4.254107.3.4.255254
6107.3.5.0/24107.3.5.1 to 107.3.5.254107.3.5.255254
7107.3.6.0/24107.3.6.1 to 107.3.6.254107.3.6.255254
8107.3.7.0/24107.3.7.1 to 107.3.7.254107.3.7.255254
9107.3.8.0/24107.3.8.1 to 107.3.8.254107.3.8.255254
10107.3.9.0/24107.3.9.1 to 107.3.9.254107.3.9.255254
11107.3.10.0/24107.3.10.1 to 107.3.10.254107.3.10.255254
12107.3.11.0/24107.3.11.1 to 107.3.11.254107.3.11.255254
13107.3.12.0/24107.3.12.1 to 107.3.12.254107.3.12.255254
14107.3.13.0/24107.3.13.1 to 107.3.13.254107.3.13.255254
15107.3.14.0/24107.3.14.1 to 107.3.14.254107.3.14.255254
16107.3.15.0/24107.3.15.1 to 107.3.15.254107.3.15.255254
17107.3.16.0/24107.3.16.1 to 107.3.16.254107.3.16.255254
18107.3.17.0/24107.3.17.1 to 107.3.17.254107.3.17.255254
19107.3.18.0/24107.3.18.1 to 107.3.18.254107.3.18.255254
20107.3.19.0/24107.3.19.1 to 107.3.19.254107.3.19.255254
21107.3.20.0/24107.3.20.1 to 107.3.20.254107.3.20.255254
22107.3.21.0/24107.3.21.1 to 107.3.21.254107.3.21.255254
23107.3.22.0/24107.3.22.1 to 107.3.22.254107.3.22.255254
24107.3.23.0/24107.3.23.1 to 107.3.23.254107.3.23.255254
25107.3.24.0/24107.3.24.1 to 107.3.24.254107.3.24.255254
26107.3.25.0/24107.3.25.1 to 107.3.25.254107.3.25.255254
27107.3.26.0/24107.3.26.1 to 107.3.26.254107.3.26.255254
28107.3.27.0/24107.3.27.1 to 107.3.27.254107.3.27.255254
29107.3.28.0/24107.3.28.1 to 107.3.28.254107.3.28.255254
30107.3.29.0/24107.3.29.1 to 107.3.29.254107.3.29.255254
31107.3.30.0/24107.3.30.1 to 107.3.30.254107.3.30.255254
32107.3.31.0/24107.3.31.1 to 107.3.31.254107.3.31.255254
33107.3.32.0/24107.3.32.1 to 107.3.32.254107.3.32.255254
34107.3.33.0/24107.3.33.1 to 107.3.33.254107.3.33.255254
35107.3.34.0/24107.3.34.1 to 107.3.34.254107.3.34.255254
36107.3.35.0/24107.3.35.1 to 107.3.35.254107.3.35.255254
37107.3.36.0/24107.3.36.1 to 107.3.36.254107.3.36.255254
38107.3.37.0/24107.3.37.1 to 107.3.37.254107.3.37.255254
39107.3.38.0/24107.3.38.1 to 107.3.38.254107.3.38.255254
40107.3.39.0/24107.3.39.1 to 107.3.39.254107.3.39.255254
41107.3.40.0/24107.3.40.1 to 107.3.40.254107.3.40.255254
42107.3.41.0/24107.3.41.1 to 107.3.41.254107.3.41.255254
43107.3.42.0/24107.3.42.1 to 107.3.42.254107.3.42.255254
44107.3.43.0/24107.3.43.1 to 107.3.43.254107.3.43.255254
45107.3.44.0/24107.3.44.1 to 107.3.44.254107.3.44.255254
46107.3.45.0/24107.3.45.1 to 107.3.45.254107.3.45.255254
47107.3.46.0/24107.3.46.1 to 107.3.46.254107.3.46.255254
48107.3.47.0/24107.3.47.1 to 107.3.47.254107.3.47.255254
49107.3.48.0/24107.3.48.1 to 107.3.48.254107.3.48.255254
50107.3.49.0/24107.3.49.1 to 107.3.49.254107.3.49.255254
51107.3.50.0/24107.3.50.1 to 107.3.50.254107.3.50.255254
52107.3.51.0/24107.3.51.1 to 107.3.51.254107.3.51.255254
53107.3.52.0/24107.3.52.1 to 107.3.52.254107.3.52.255254
54107.3.53.0/24107.3.53.1 to 107.3.53.254107.3.53.255254
55107.3.54.0/24107.3.54.1 to 107.3.54.254107.3.54.255254
56107.3.55.0/24107.3.55.1 to 107.3.55.254107.3.55.255254
57107.3.56.0/24107.3.56.1 to 107.3.56.254107.3.56.255254
58107.3.57.0/24107.3.57.1 to 107.3.57.254107.3.57.255254
59107.3.58.0/24107.3.58.1 to 107.3.58.254107.3.58.255254
60107.3.59.0/24107.3.59.1 to 107.3.59.254107.3.59.255254
61107.3.60.0/24107.3.60.1 to 107.3.60.254107.3.60.255254
62107.3.61.0/24107.3.61.1 to 107.3.61.254107.3.61.255254
63107.3.62.0/24107.3.62.1 to 107.3.62.254107.3.62.255254
64107.3.63.0/24107.3.63.1 to 107.3.63.254107.3.63.255254
65107.3.64.0/24107.3.64.1 to 107.3.64.254107.3.64.255254
66107.3.65.0/24107.3.65.1 to 107.3.65.254107.3.65.255254
67107.3.66.0/24107.3.66.1 to 107.3.66.254107.3.66.255254
68107.3.67.0/24107.3.67.1 to 107.3.67.254107.3.67.255254
69107.3.68.0/24107.3.68.1 to 107.3.68.254107.3.68.255254
70107.3.69.0/24107.3.69.1 to 107.3.69.254107.3.69.255254
71107.3.70.0/24107.3.70.1 to 107.3.70.254107.3.70.255254
72107.3.71.0/24107.3.71.1 to 107.3.71.254107.3.71.255254
73107.3.72.0/24107.3.72.1 to 107.3.72.254107.3.72.255254
74107.3.73.0/24107.3.73.1 to 107.3.73.254107.3.73.255254
75107.3.74.0/24107.3.74.1 to 107.3.74.254107.3.74.255254
76107.3.75.0/24107.3.75.1 to 107.3.75.254107.3.75.255254
77107.3.76.0/24107.3.76.1 to 107.3.76.254107.3.76.255254
78107.3.77.0/24107.3.77.1 to 107.3.77.254107.3.77.255254
79107.3.78.0/24107.3.78.1 to 107.3.78.254107.3.78.255254
80107.3.79.0/24107.3.79.1 to 107.3.79.254107.3.79.255254
81107.3.80.0/24107.3.80.1 to 107.3.80.254107.3.80.255254
82107.3.81.0/24107.3.81.1 to 107.3.81.254107.3.81.255254
83107.3.82.0/24107.3.82.1 to 107.3.82.254107.3.82.255254
84107.3.83.0/24107.3.83.1 to 107.3.83.254107.3.83.255254
85107.3.84.0/24107.3.84.1 to 107.3.84.254107.3.84.255254
86107.3.85.0/24107.3.85.1 to 107.3.85.254107.3.85.255254
87107.3.86.0/24107.3.86.1 to 107.3.86.254107.3.86.255254
88107.3.87.0/24107.3.87.1 to 107.3.87.254107.3.87.255254
89107.3.88.0/24107.3.88.1 to 107.3.88.254107.3.88.255254
90107.3.89.0/24107.3.89.1 to 107.3.89.254107.3.89.255254
91107.3.90.0/24107.3.90.1 to 107.3.90.254107.3.90.255254
92107.3.91.0/24107.3.91.1 to 107.3.91.254107.3.91.255254
93107.3.92.0/24107.3.92.1 to 107.3.92.254107.3.92.255254
94107.3.93.0/24107.3.93.1 to 107.3.93.254107.3.93.255254
95107.3.94.0/24107.3.94.1 to 107.3.94.254107.3.94.255254
96107.3.95.0/24107.3.95.1 to 107.3.95.254107.3.95.255254
97107.3.96.0/24107.3.96.1 to 107.3.96.254107.3.96.255254
98107.3.97.0/24107.3.97.1 to 107.3.97.254107.3.97.255254
99107.3.98.0/24107.3.98.1 to 107.3.98.254107.3.98.255254
100107.3.99.0/24107.3.99.1 to 107.3.99.254107.3.99.255254
101107.3.100.0/24107.3.100.1 to 107.3.100.254107.3.100.255254
102107.3.101.0/24107.3.101.1 to 107.3.101.254107.3.101.255254
103107.3.102.0/24107.3.102.1 to 107.3.102.254107.3.102.255254
104107.3.103.0/24107.3.103.1 to 107.3.103.254107.3.103.255254
105107.3.104.0/24107.3.104.1 to 107.3.104.254107.3.104.255254
106107.3.105.0/24107.3.105.1 to 107.3.105.254107.3.105.255254
107107.3.106.0/24107.3.106.1 to 107.3.106.254107.3.106.255254
108107.3.107.0/24107.3.107.1 to 107.3.107.254107.3.107.255254
109107.3.108.0/24107.3.108.1 to 107.3.108.254107.3.108.255254
110107.3.109.0/24107.3.109.1 to 107.3.109.254107.3.109.255254
111107.3.110.0/24107.3.110.1 to 107.3.110.254107.3.110.255254
112107.3.111.0/24107.3.111.1 to 107.3.111.254107.3.111.255254
113107.3.112.0/24107.3.112.1 to 107.3.112.254107.3.112.255254
114107.3.113.0/24107.3.113.1 to 107.3.113.254107.3.113.255254
115107.3.114.0/24107.3.114.1 to 107.3.114.254107.3.114.255254
116107.3.115.0/24107.3.115.1 to 107.3.115.254107.3.115.255254
117107.3.116.0/24107.3.116.1 to 107.3.116.254107.3.116.255254
118107.3.117.0/24107.3.117.1 to 107.3.117.254107.3.117.255254
119107.3.118.0/24107.3.118.1 to 107.3.118.254107.3.118.255254
120107.3.119.0/24107.3.119.1 to 107.3.119.254107.3.119.255254
121107.3.120.0/24107.3.120.1 to 107.3.120.254107.3.120.255254
122107.3.121.0/24107.3.121.1 to 107.3.121.254107.3.121.255254
123107.3.122.0/24107.3.122.1 to 107.3.122.254107.3.122.255254
124107.3.123.0/24107.3.123.1 to 107.3.123.254107.3.123.255254
125107.3.124.0/24107.3.124.1 to 107.3.124.254107.3.124.255254
126107.3.125.0/24107.3.125.1 to 107.3.125.254107.3.125.255254
127107.3.126.0/24107.3.126.1 to 107.3.126.254107.3.126.255254
128107.3.127.0/24107.3.127.1 to 107.3.127.254107.3.127.255254
129107.3.128.0/24107.3.128.1 to 107.3.128.254107.3.128.255254
130107.3.129.0/24107.3.129.1 to 107.3.129.254107.3.129.255254
131107.3.130.0/24107.3.130.1 to 107.3.130.254107.3.130.255254
132107.3.131.0/24107.3.131.1 to 107.3.131.254107.3.131.255254
133107.3.132.0/24107.3.132.1 to 107.3.132.254107.3.132.255254
134107.3.133.0/24107.3.133.1 to 107.3.133.254107.3.133.255254
135107.3.134.0/24107.3.134.1 to 107.3.134.254107.3.134.255254
136107.3.135.0/24107.3.135.1 to 107.3.135.254107.3.135.255254
137107.3.136.0/24107.3.136.1 to 107.3.136.254107.3.136.255254
138107.3.137.0/24107.3.137.1 to 107.3.137.254107.3.137.255254
139107.3.138.0/24107.3.138.1 to 107.3.138.254107.3.138.255254
140107.3.139.0/24107.3.139.1 to 107.3.139.254107.3.139.255254
141107.3.140.0/24107.3.140.1 to 107.3.140.254107.3.140.255254
142107.3.141.0/24107.3.141.1 to 107.3.141.254107.3.141.255254
143107.3.142.0/24107.3.142.1 to 107.3.142.254107.3.142.255254
144107.3.143.0/24107.3.143.1 to 107.3.143.254107.3.143.255254
145107.3.144.0/24107.3.144.1 to 107.3.144.254107.3.144.255254
146107.3.145.0/24107.3.145.1 to 107.3.145.254107.3.145.255254
147107.3.146.0/24107.3.146.1 to 107.3.146.254107.3.146.255254
148107.3.147.0/24107.3.147.1 to 107.3.147.254107.3.147.255254
149107.3.148.0/24107.3.148.1 to 107.3.148.254107.3.148.255254
150107.3.149.0/24107.3.149.1 to 107.3.149.254107.3.149.255254
151107.3.150.0/24107.3.150.1 to 107.3.150.254107.3.150.255254
152107.3.151.0/24107.3.151.1 to 107.3.151.254107.3.151.255254
153107.3.152.0/24107.3.152.1 to 107.3.152.254107.3.152.255254
154107.3.153.0/24107.3.153.1 to 107.3.153.254107.3.153.255254
155107.3.154.0/24107.3.154.1 to 107.3.154.254107.3.154.255254
156107.3.155.0/24107.3.155.1 to 107.3.155.254107.3.155.255254
157107.3.156.0/24107.3.156.1 to 107.3.156.254107.3.156.255254
158107.3.157.0/24107.3.157.1 to 107.3.157.254107.3.157.255254
159107.3.158.0/24107.3.158.1 to 107.3.158.254107.3.158.255254
160107.3.159.0/24107.3.159.1 to 107.3.159.254107.3.159.255254
161107.3.160.0/24107.3.160.1 to 107.3.160.254107.3.160.255254
162107.3.161.0/24107.3.161.1 to 107.3.161.254107.3.161.255254
163107.3.162.0/24107.3.162.1 to 107.3.162.254107.3.162.255254
164107.3.163.0/24107.3.163.1 to 107.3.163.254107.3.163.255254
165107.3.164.0/24107.3.164.1 to 107.3.164.254107.3.164.255254
166107.3.165.0/24107.3.165.1 to 107.3.165.254107.3.165.255254
167107.3.166.0/24107.3.166.1 to 107.3.166.254107.3.166.255254
168107.3.167.0/24107.3.167.1 to 107.3.167.254107.3.167.255254
169107.3.168.0/24107.3.168.1 to 107.3.168.254107.3.168.255254
170107.3.169.0/24107.3.169.1 to 107.3.169.254107.3.169.255254
171107.3.170.0/24107.3.170.1 to 107.3.170.254107.3.170.255254
172107.3.171.0/24107.3.171.1 to 107.3.171.254107.3.171.255254
173107.3.172.0/24107.3.172.1 to 107.3.172.254107.3.172.255254
174107.3.173.0/24107.3.173.1 to 107.3.173.254107.3.173.255254
175107.3.174.0/24107.3.174.1 to 107.3.174.254107.3.174.255254
176107.3.175.0/24107.3.175.1 to 107.3.175.254107.3.175.255254
177107.3.176.0/24107.3.176.1 to 107.3.176.254107.3.176.255254
178107.3.177.0/24107.3.177.1 to 107.3.177.254107.3.177.255254
179107.3.178.0/24107.3.178.1 to 107.3.178.254107.3.178.255254
180107.3.179.0/24107.3.179.1 to 107.3.179.254107.3.179.255254
181107.3.180.0/24107.3.180.1 to 107.3.180.254107.3.180.255254
182107.3.181.0/24107.3.181.1 to 107.3.181.254107.3.181.255254
183107.3.182.0/24107.3.182.1 to 107.3.182.254107.3.182.255254
184107.3.183.0/24107.3.183.1 to 107.3.183.254107.3.183.255254
185107.3.184.0/24107.3.184.1 to 107.3.184.254107.3.184.255254
186107.3.185.0/24107.3.185.1 to 107.3.185.254107.3.185.255254
187107.3.186.0/24107.3.186.1 to 107.3.186.254107.3.186.255254
188107.3.187.0/24107.3.187.1 to 107.3.187.254107.3.187.255254
189107.3.188.0/24107.3.188.1 to 107.3.188.254107.3.188.255254
190107.3.189.0/24107.3.189.1 to 107.3.189.254107.3.189.255254
191107.3.190.0/24107.3.190.1 to 107.3.190.254107.3.190.255254
192107.3.191.0/24107.3.191.1 to 107.3.191.254107.3.191.255254
193107.3.192.0/24107.3.192.1 to 107.3.192.254107.3.192.255254
194107.3.193.0/24107.3.193.1 to 107.3.193.254107.3.193.255254
195107.3.194.0/24107.3.194.1 to 107.3.194.254107.3.194.255254
196107.3.195.0/24107.3.195.1 to 107.3.195.254107.3.195.255254
197107.3.196.0/24107.3.196.1 to 107.3.196.254107.3.196.255254
198107.3.197.0/24107.3.197.1 to 107.3.197.254107.3.197.255254
199107.3.198.0/24107.3.198.1 to 107.3.198.254107.3.198.255254
200107.3.199.0/24107.3.199.1 to 107.3.199.254107.3.199.255254
201107.3.200.0/24107.3.200.1 to 107.3.200.254107.3.200.255254
202107.3.201.0/24107.3.201.1 to 107.3.201.254107.3.201.255254
203107.3.202.0/24107.3.202.1 to 107.3.202.254107.3.202.255254
204107.3.203.0/24107.3.203.1 to 107.3.203.254107.3.203.255254
205107.3.204.0/24107.3.204.1 to 107.3.204.254107.3.204.255254
206107.3.205.0/24107.3.205.1 to 107.3.205.254107.3.205.255254
207107.3.206.0/24107.3.206.1 to 107.3.206.254107.3.206.255254
208107.3.207.0/24107.3.207.1 to 107.3.207.254107.3.207.255254
209107.3.208.0/24107.3.208.1 to 107.3.208.254107.3.208.255254
210107.3.209.0/24107.3.209.1 to 107.3.209.254107.3.209.255254
211107.3.210.0/24107.3.210.1 to 107.3.210.254107.3.210.255254
212107.3.211.0/24107.3.211.1 to 107.3.211.254107.3.211.255254
213107.3.212.0/24107.3.212.1 to 107.3.212.254107.3.212.255254
214107.3.213.0/24107.3.213.1 to 107.3.213.254107.3.213.255254
215107.3.214.0/24107.3.214.1 to 107.3.214.254107.3.214.255254
216107.3.215.0/24107.3.215.1 to 107.3.215.254107.3.215.255254
217107.3.216.0/24107.3.216.1 to 107.3.216.254107.3.216.255254
218107.3.217.0/24107.3.217.1 to 107.3.217.254107.3.217.255254
219107.3.218.0/24107.3.218.1 to 107.3.218.254107.3.218.255254
220107.3.219.0/24107.3.219.1 to 107.3.219.254107.3.219.255254
221107.3.220.0/24107.3.220.1 to 107.3.220.254107.3.220.255254
222107.3.221.0/24107.3.221.1 to 107.3.221.254107.3.221.255254
223107.3.222.0/24107.3.222.1 to 107.3.222.254107.3.222.255254
224107.3.223.0/24107.3.223.1 to 107.3.223.254107.3.223.255254
225107.3.224.0/24107.3.224.1 to 107.3.224.254107.3.224.255254
226107.3.225.0/24107.3.225.1 to 107.3.225.254107.3.225.255254
227107.3.226.0/24107.3.226.1 to 107.3.226.254107.3.226.255254
228107.3.227.0/24107.3.227.1 to 107.3.227.254107.3.227.255254
229107.3.228.0/24107.3.228.1 to 107.3.228.254107.3.228.255254
230107.3.229.0/24107.3.229.1 to 107.3.229.254107.3.229.255254
231107.3.230.0/24107.3.230.1 to 107.3.230.254107.3.230.255254
232107.3.231.0/24107.3.231.1 to 107.3.231.254107.3.231.255254
233107.3.232.0/24107.3.232.1 to 107.3.232.254107.3.232.255254
234107.3.233.0/24107.3.233.1 to 107.3.233.254107.3.233.255254
235107.3.234.0/24107.3.234.1 to 107.3.234.254107.3.234.255254
236107.3.235.0/24107.3.235.1 to 107.3.235.254107.3.235.255254
237107.3.236.0/24107.3.236.1 to 107.3.236.254107.3.236.255254
238107.3.237.0/24107.3.237.1 to 107.3.237.254107.3.237.255254
239107.3.238.0/24107.3.238.1 to 107.3.238.254107.3.238.255254
240107.3.239.0/24107.3.239.1 to 107.3.239.254107.3.239.255254
241107.3.240.0/24107.3.240.1 to 107.3.240.254107.3.240.255254
242107.3.241.0/24107.3.241.1 to 107.3.241.254107.3.241.255254
243107.3.242.0/24107.3.242.1 to 107.3.242.254107.3.242.255254
244107.3.243.0/24107.3.243.1 to 107.3.243.254107.3.243.255254
245107.3.244.0/24107.3.244.1 to 107.3.244.254107.3.244.255254
246107.3.245.0/24107.3.245.1 to 107.3.245.254107.3.245.255254
247107.3.246.0/24107.3.246.1 to 107.3.246.254107.3.246.255254
248107.3.247.0/24107.3.247.1 to 107.3.247.254107.3.247.255254
249107.3.248.0/24107.3.248.1 to 107.3.248.254107.3.248.255254
250107.3.249.0/24107.3.249.1 to 107.3.249.254107.3.249.255254
251107.3.250.0/24107.3.250.1 to 107.3.250.254107.3.250.255254
252107.3.251.0/24107.3.251.1 to 107.3.251.254107.3.251.255254
253107.3.252.0/24107.3.252.1 to 107.3.252.254107.3.252.255254
254107.3.253.0/24107.3.253.1 to 107.3.253.254107.3.253.255254
255107.3.254.0/24107.3.254.1 to 107.3.254.254107.3.254.255254
256107.3.255.0/24107.3.255.1 to 107.3.255.254107.3.255.255254

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.