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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.

Network198.18.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
198.18.0.0
Broadcast address
198.19.255.255
First usable
198.18.0.1
Last usable
198.19.255.254
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
Benchmarking 198.18.0.0/15
Network equipment testing (RFC 2544)
Old class
C (default /24)
As numbers
Hex C6120000 · Integer 3323068416 to 3323199487
Reverse DNS zones
18.198.in-addr.arpa
19.198.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
Address11000110.00010010.00000000.00000000198.18.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network11000110.00010010.00000000.00000000198.18.0.0
Broadcast11000110.00010011.11111111.11111111198.19.255.255
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)

198.18.0.0/15 makes 256 subnets of /23.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1198.18.0.0/23198.18.0.1 to 198.18.1.254198.18.1.255510
2198.18.2.0/23198.18.2.1 to 198.18.3.254198.18.3.255510
3198.18.4.0/23198.18.4.1 to 198.18.5.254198.18.5.255510
4198.18.6.0/23198.18.6.1 to 198.18.7.254198.18.7.255510
5198.18.8.0/23198.18.8.1 to 198.18.9.254198.18.9.255510
6198.18.10.0/23198.18.10.1 to 198.18.11.254198.18.11.255510
7198.18.12.0/23198.18.12.1 to 198.18.13.254198.18.13.255510
8198.18.14.0/23198.18.14.1 to 198.18.15.254198.18.15.255510
9198.18.16.0/23198.18.16.1 to 198.18.17.254198.18.17.255510
10198.18.18.0/23198.18.18.1 to 198.18.19.254198.18.19.255510
11198.18.20.0/23198.18.20.1 to 198.18.21.254198.18.21.255510
12198.18.22.0/23198.18.22.1 to 198.18.23.254198.18.23.255510
13198.18.24.0/23198.18.24.1 to 198.18.25.254198.18.25.255510
14198.18.26.0/23198.18.26.1 to 198.18.27.254198.18.27.255510
15198.18.28.0/23198.18.28.1 to 198.18.29.254198.18.29.255510
16198.18.30.0/23198.18.30.1 to 198.18.31.254198.18.31.255510
17198.18.32.0/23198.18.32.1 to 198.18.33.254198.18.33.255510
18198.18.34.0/23198.18.34.1 to 198.18.35.254198.18.35.255510
19198.18.36.0/23198.18.36.1 to 198.18.37.254198.18.37.255510
20198.18.38.0/23198.18.38.1 to 198.18.39.254198.18.39.255510
21198.18.40.0/23198.18.40.1 to 198.18.41.254198.18.41.255510
22198.18.42.0/23198.18.42.1 to 198.18.43.254198.18.43.255510
23198.18.44.0/23198.18.44.1 to 198.18.45.254198.18.45.255510
24198.18.46.0/23198.18.46.1 to 198.18.47.254198.18.47.255510
25198.18.48.0/23198.18.48.1 to 198.18.49.254198.18.49.255510
26198.18.50.0/23198.18.50.1 to 198.18.51.254198.18.51.255510
27198.18.52.0/23198.18.52.1 to 198.18.53.254198.18.53.255510
28198.18.54.0/23198.18.54.1 to 198.18.55.254198.18.55.255510
29198.18.56.0/23198.18.56.1 to 198.18.57.254198.18.57.255510
30198.18.58.0/23198.18.58.1 to 198.18.59.254198.18.59.255510
31198.18.60.0/23198.18.60.1 to 198.18.61.254198.18.61.255510
32198.18.62.0/23198.18.62.1 to 198.18.63.254198.18.63.255510
33198.18.64.0/23198.18.64.1 to 198.18.65.254198.18.65.255510
34198.18.66.0/23198.18.66.1 to 198.18.67.254198.18.67.255510
35198.18.68.0/23198.18.68.1 to 198.18.69.254198.18.69.255510
36198.18.70.0/23198.18.70.1 to 198.18.71.254198.18.71.255510
37198.18.72.0/23198.18.72.1 to 198.18.73.254198.18.73.255510
38198.18.74.0/23198.18.74.1 to 198.18.75.254198.18.75.255510
39198.18.76.0/23198.18.76.1 to 198.18.77.254198.18.77.255510
40198.18.78.0/23198.18.78.1 to 198.18.79.254198.18.79.255510
41198.18.80.0/23198.18.80.1 to 198.18.81.254198.18.81.255510
42198.18.82.0/23198.18.82.1 to 198.18.83.254198.18.83.255510
43198.18.84.0/23198.18.84.1 to 198.18.85.254198.18.85.255510
44198.18.86.0/23198.18.86.1 to 198.18.87.254198.18.87.255510
45198.18.88.0/23198.18.88.1 to 198.18.89.254198.18.89.255510
46198.18.90.0/23198.18.90.1 to 198.18.91.254198.18.91.255510
47198.18.92.0/23198.18.92.1 to 198.18.93.254198.18.93.255510
48198.18.94.0/23198.18.94.1 to 198.18.95.254198.18.95.255510
49198.18.96.0/23198.18.96.1 to 198.18.97.254198.18.97.255510
50198.18.98.0/23198.18.98.1 to 198.18.99.254198.18.99.255510
51198.18.100.0/23198.18.100.1 to 198.18.101.254198.18.101.255510
52198.18.102.0/23198.18.102.1 to 198.18.103.254198.18.103.255510
53198.18.104.0/23198.18.104.1 to 198.18.105.254198.18.105.255510
54198.18.106.0/23198.18.106.1 to 198.18.107.254198.18.107.255510
55198.18.108.0/23198.18.108.1 to 198.18.109.254198.18.109.255510
56198.18.110.0/23198.18.110.1 to 198.18.111.254198.18.111.255510
57198.18.112.0/23198.18.112.1 to 198.18.113.254198.18.113.255510
58198.18.114.0/23198.18.114.1 to 198.18.115.254198.18.115.255510
59198.18.116.0/23198.18.116.1 to 198.18.117.254198.18.117.255510
60198.18.118.0/23198.18.118.1 to 198.18.119.254198.18.119.255510
61198.18.120.0/23198.18.120.1 to 198.18.121.254198.18.121.255510
62198.18.122.0/23198.18.122.1 to 198.18.123.254198.18.123.255510
63198.18.124.0/23198.18.124.1 to 198.18.125.254198.18.125.255510
64198.18.126.0/23198.18.126.1 to 198.18.127.254198.18.127.255510
65198.18.128.0/23198.18.128.1 to 198.18.129.254198.18.129.255510
66198.18.130.0/23198.18.130.1 to 198.18.131.254198.18.131.255510
67198.18.132.0/23198.18.132.1 to 198.18.133.254198.18.133.255510
68198.18.134.0/23198.18.134.1 to 198.18.135.254198.18.135.255510
69198.18.136.0/23198.18.136.1 to 198.18.137.254198.18.137.255510
70198.18.138.0/23198.18.138.1 to 198.18.139.254198.18.139.255510
71198.18.140.0/23198.18.140.1 to 198.18.141.254198.18.141.255510
72198.18.142.0/23198.18.142.1 to 198.18.143.254198.18.143.255510
73198.18.144.0/23198.18.144.1 to 198.18.145.254198.18.145.255510
74198.18.146.0/23198.18.146.1 to 198.18.147.254198.18.147.255510
75198.18.148.0/23198.18.148.1 to 198.18.149.254198.18.149.255510
76198.18.150.0/23198.18.150.1 to 198.18.151.254198.18.151.255510
77198.18.152.0/23198.18.152.1 to 198.18.153.254198.18.153.255510
78198.18.154.0/23198.18.154.1 to 198.18.155.254198.18.155.255510
79198.18.156.0/23198.18.156.1 to 198.18.157.254198.18.157.255510
80198.18.158.0/23198.18.158.1 to 198.18.159.254198.18.159.255510
81198.18.160.0/23198.18.160.1 to 198.18.161.254198.18.161.255510
82198.18.162.0/23198.18.162.1 to 198.18.163.254198.18.163.255510
83198.18.164.0/23198.18.164.1 to 198.18.165.254198.18.165.255510
84198.18.166.0/23198.18.166.1 to 198.18.167.254198.18.167.255510
85198.18.168.0/23198.18.168.1 to 198.18.169.254198.18.169.255510
86198.18.170.0/23198.18.170.1 to 198.18.171.254198.18.171.255510
87198.18.172.0/23198.18.172.1 to 198.18.173.254198.18.173.255510
88198.18.174.0/23198.18.174.1 to 198.18.175.254198.18.175.255510
89198.18.176.0/23198.18.176.1 to 198.18.177.254198.18.177.255510
90198.18.178.0/23198.18.178.1 to 198.18.179.254198.18.179.255510
91198.18.180.0/23198.18.180.1 to 198.18.181.254198.18.181.255510
92198.18.182.0/23198.18.182.1 to 198.18.183.254198.18.183.255510
93198.18.184.0/23198.18.184.1 to 198.18.185.254198.18.185.255510
94198.18.186.0/23198.18.186.1 to 198.18.187.254198.18.187.255510
95198.18.188.0/23198.18.188.1 to 198.18.189.254198.18.189.255510
96198.18.190.0/23198.18.190.1 to 198.18.191.254198.18.191.255510
97198.18.192.0/23198.18.192.1 to 198.18.193.254198.18.193.255510
98198.18.194.0/23198.18.194.1 to 198.18.195.254198.18.195.255510
99198.18.196.0/23198.18.196.1 to 198.18.197.254198.18.197.255510
100198.18.198.0/23198.18.198.1 to 198.18.199.254198.18.199.255510
101198.18.200.0/23198.18.200.1 to 198.18.201.254198.18.201.255510
102198.18.202.0/23198.18.202.1 to 198.18.203.254198.18.203.255510
103198.18.204.0/23198.18.204.1 to 198.18.205.254198.18.205.255510
104198.18.206.0/23198.18.206.1 to 198.18.207.254198.18.207.255510
105198.18.208.0/23198.18.208.1 to 198.18.209.254198.18.209.255510
106198.18.210.0/23198.18.210.1 to 198.18.211.254198.18.211.255510
107198.18.212.0/23198.18.212.1 to 198.18.213.254198.18.213.255510
108198.18.214.0/23198.18.214.1 to 198.18.215.254198.18.215.255510
109198.18.216.0/23198.18.216.1 to 198.18.217.254198.18.217.255510
110198.18.218.0/23198.18.218.1 to 198.18.219.254198.18.219.255510
111198.18.220.0/23198.18.220.1 to 198.18.221.254198.18.221.255510
112198.18.222.0/23198.18.222.1 to 198.18.223.254198.18.223.255510
113198.18.224.0/23198.18.224.1 to 198.18.225.254198.18.225.255510
114198.18.226.0/23198.18.226.1 to 198.18.227.254198.18.227.255510
115198.18.228.0/23198.18.228.1 to 198.18.229.254198.18.229.255510
116198.18.230.0/23198.18.230.1 to 198.18.231.254198.18.231.255510
117198.18.232.0/23198.18.232.1 to 198.18.233.254198.18.233.255510
118198.18.234.0/23198.18.234.1 to 198.18.235.254198.18.235.255510
119198.18.236.0/23198.18.236.1 to 198.18.237.254198.18.237.255510
120198.18.238.0/23198.18.238.1 to 198.18.239.254198.18.239.255510
121198.18.240.0/23198.18.240.1 to 198.18.241.254198.18.241.255510
122198.18.242.0/23198.18.242.1 to 198.18.243.254198.18.243.255510
123198.18.244.0/23198.18.244.1 to 198.18.245.254198.18.245.255510
124198.18.246.0/23198.18.246.1 to 198.18.247.254198.18.247.255510
125198.18.248.0/23198.18.248.1 to 198.18.249.254198.18.249.255510
126198.18.250.0/23198.18.250.1 to 198.18.251.254198.18.251.255510
127198.18.252.0/23198.18.252.1 to 198.18.253.254198.18.253.255510
128198.18.254.0/23198.18.254.1 to 198.18.255.254198.18.255.255510
129198.19.0.0/23198.19.0.1 to 198.19.1.254198.19.1.255510
130198.19.2.0/23198.19.2.1 to 198.19.3.254198.19.3.255510
131198.19.4.0/23198.19.4.1 to 198.19.5.254198.19.5.255510
132198.19.6.0/23198.19.6.1 to 198.19.7.254198.19.7.255510
133198.19.8.0/23198.19.8.1 to 198.19.9.254198.19.9.255510
134198.19.10.0/23198.19.10.1 to 198.19.11.254198.19.11.255510
135198.19.12.0/23198.19.12.1 to 198.19.13.254198.19.13.255510
136198.19.14.0/23198.19.14.1 to 198.19.15.254198.19.15.255510
137198.19.16.0/23198.19.16.1 to 198.19.17.254198.19.17.255510
138198.19.18.0/23198.19.18.1 to 198.19.19.254198.19.19.255510
139198.19.20.0/23198.19.20.1 to 198.19.21.254198.19.21.255510
140198.19.22.0/23198.19.22.1 to 198.19.23.254198.19.23.255510
141198.19.24.0/23198.19.24.1 to 198.19.25.254198.19.25.255510
142198.19.26.0/23198.19.26.1 to 198.19.27.254198.19.27.255510
143198.19.28.0/23198.19.28.1 to 198.19.29.254198.19.29.255510
144198.19.30.0/23198.19.30.1 to 198.19.31.254198.19.31.255510
145198.19.32.0/23198.19.32.1 to 198.19.33.254198.19.33.255510
146198.19.34.0/23198.19.34.1 to 198.19.35.254198.19.35.255510
147198.19.36.0/23198.19.36.1 to 198.19.37.254198.19.37.255510
148198.19.38.0/23198.19.38.1 to 198.19.39.254198.19.39.255510
149198.19.40.0/23198.19.40.1 to 198.19.41.254198.19.41.255510
150198.19.42.0/23198.19.42.1 to 198.19.43.254198.19.43.255510
151198.19.44.0/23198.19.44.1 to 198.19.45.254198.19.45.255510
152198.19.46.0/23198.19.46.1 to 198.19.47.254198.19.47.255510
153198.19.48.0/23198.19.48.1 to 198.19.49.254198.19.49.255510
154198.19.50.0/23198.19.50.1 to 198.19.51.254198.19.51.255510
155198.19.52.0/23198.19.52.1 to 198.19.53.254198.19.53.255510
156198.19.54.0/23198.19.54.1 to 198.19.55.254198.19.55.255510
157198.19.56.0/23198.19.56.1 to 198.19.57.254198.19.57.255510
158198.19.58.0/23198.19.58.1 to 198.19.59.254198.19.59.255510
159198.19.60.0/23198.19.60.1 to 198.19.61.254198.19.61.255510
160198.19.62.0/23198.19.62.1 to 198.19.63.254198.19.63.255510
161198.19.64.0/23198.19.64.1 to 198.19.65.254198.19.65.255510
162198.19.66.0/23198.19.66.1 to 198.19.67.254198.19.67.255510
163198.19.68.0/23198.19.68.1 to 198.19.69.254198.19.69.255510
164198.19.70.0/23198.19.70.1 to 198.19.71.254198.19.71.255510
165198.19.72.0/23198.19.72.1 to 198.19.73.254198.19.73.255510
166198.19.74.0/23198.19.74.1 to 198.19.75.254198.19.75.255510
167198.19.76.0/23198.19.76.1 to 198.19.77.254198.19.77.255510
168198.19.78.0/23198.19.78.1 to 198.19.79.254198.19.79.255510
169198.19.80.0/23198.19.80.1 to 198.19.81.254198.19.81.255510
170198.19.82.0/23198.19.82.1 to 198.19.83.254198.19.83.255510
171198.19.84.0/23198.19.84.1 to 198.19.85.254198.19.85.255510
172198.19.86.0/23198.19.86.1 to 198.19.87.254198.19.87.255510
173198.19.88.0/23198.19.88.1 to 198.19.89.254198.19.89.255510
174198.19.90.0/23198.19.90.1 to 198.19.91.254198.19.91.255510
175198.19.92.0/23198.19.92.1 to 198.19.93.254198.19.93.255510
176198.19.94.0/23198.19.94.1 to 198.19.95.254198.19.95.255510
177198.19.96.0/23198.19.96.1 to 198.19.97.254198.19.97.255510
178198.19.98.0/23198.19.98.1 to 198.19.99.254198.19.99.255510
179198.19.100.0/23198.19.100.1 to 198.19.101.254198.19.101.255510
180198.19.102.0/23198.19.102.1 to 198.19.103.254198.19.103.255510
181198.19.104.0/23198.19.104.1 to 198.19.105.254198.19.105.255510
182198.19.106.0/23198.19.106.1 to 198.19.107.254198.19.107.255510
183198.19.108.0/23198.19.108.1 to 198.19.109.254198.19.109.255510
184198.19.110.0/23198.19.110.1 to 198.19.111.254198.19.111.255510
185198.19.112.0/23198.19.112.1 to 198.19.113.254198.19.113.255510
186198.19.114.0/23198.19.114.1 to 198.19.115.254198.19.115.255510
187198.19.116.0/23198.19.116.1 to 198.19.117.254198.19.117.255510
188198.19.118.0/23198.19.118.1 to 198.19.119.254198.19.119.255510
189198.19.120.0/23198.19.120.1 to 198.19.121.254198.19.121.255510
190198.19.122.0/23198.19.122.1 to 198.19.123.254198.19.123.255510
191198.19.124.0/23198.19.124.1 to 198.19.125.254198.19.125.255510
192198.19.126.0/23198.19.126.1 to 198.19.127.254198.19.127.255510
193198.19.128.0/23198.19.128.1 to 198.19.129.254198.19.129.255510
194198.19.130.0/23198.19.130.1 to 198.19.131.254198.19.131.255510
195198.19.132.0/23198.19.132.1 to 198.19.133.254198.19.133.255510
196198.19.134.0/23198.19.134.1 to 198.19.135.254198.19.135.255510
197198.19.136.0/23198.19.136.1 to 198.19.137.254198.19.137.255510
198198.19.138.0/23198.19.138.1 to 198.19.139.254198.19.139.255510
199198.19.140.0/23198.19.140.1 to 198.19.141.254198.19.141.255510
200198.19.142.0/23198.19.142.1 to 198.19.143.254198.19.143.255510
201198.19.144.0/23198.19.144.1 to 198.19.145.254198.19.145.255510
202198.19.146.0/23198.19.146.1 to 198.19.147.254198.19.147.255510
203198.19.148.0/23198.19.148.1 to 198.19.149.254198.19.149.255510
204198.19.150.0/23198.19.150.1 to 198.19.151.254198.19.151.255510
205198.19.152.0/23198.19.152.1 to 198.19.153.254198.19.153.255510
206198.19.154.0/23198.19.154.1 to 198.19.155.254198.19.155.255510
207198.19.156.0/23198.19.156.1 to 198.19.157.254198.19.157.255510
208198.19.158.0/23198.19.158.1 to 198.19.159.254198.19.159.255510
209198.19.160.0/23198.19.160.1 to 198.19.161.254198.19.161.255510
210198.19.162.0/23198.19.162.1 to 198.19.163.254198.19.163.255510
211198.19.164.0/23198.19.164.1 to 198.19.165.254198.19.165.255510
212198.19.166.0/23198.19.166.1 to 198.19.167.254198.19.167.255510
213198.19.168.0/23198.19.168.1 to 198.19.169.254198.19.169.255510
214198.19.170.0/23198.19.170.1 to 198.19.171.254198.19.171.255510
215198.19.172.0/23198.19.172.1 to 198.19.173.254198.19.173.255510
216198.19.174.0/23198.19.174.1 to 198.19.175.254198.19.175.255510
217198.19.176.0/23198.19.176.1 to 198.19.177.254198.19.177.255510
218198.19.178.0/23198.19.178.1 to 198.19.179.254198.19.179.255510
219198.19.180.0/23198.19.180.1 to 198.19.181.254198.19.181.255510
220198.19.182.0/23198.19.182.1 to 198.19.183.254198.19.183.255510
221198.19.184.0/23198.19.184.1 to 198.19.185.254198.19.185.255510
222198.19.186.0/23198.19.186.1 to 198.19.187.254198.19.187.255510
223198.19.188.0/23198.19.188.1 to 198.19.189.254198.19.189.255510
224198.19.190.0/23198.19.190.1 to 198.19.191.254198.19.191.255510
225198.19.192.0/23198.19.192.1 to 198.19.193.254198.19.193.255510
226198.19.194.0/23198.19.194.1 to 198.19.195.254198.19.195.255510
227198.19.196.0/23198.19.196.1 to 198.19.197.254198.19.197.255510
228198.19.198.0/23198.19.198.1 to 198.19.199.254198.19.199.255510
229198.19.200.0/23198.19.200.1 to 198.19.201.254198.19.201.255510
230198.19.202.0/23198.19.202.1 to 198.19.203.254198.19.203.255510
231198.19.204.0/23198.19.204.1 to 198.19.205.254198.19.205.255510
232198.19.206.0/23198.19.206.1 to 198.19.207.254198.19.207.255510
233198.19.208.0/23198.19.208.1 to 198.19.209.254198.19.209.255510
234198.19.210.0/23198.19.210.1 to 198.19.211.254198.19.211.255510
235198.19.212.0/23198.19.212.1 to 198.19.213.254198.19.213.255510
236198.19.214.0/23198.19.214.1 to 198.19.215.254198.19.215.255510
237198.19.216.0/23198.19.216.1 to 198.19.217.254198.19.217.255510
238198.19.218.0/23198.19.218.1 to 198.19.219.254198.19.219.255510
239198.19.220.0/23198.19.220.1 to 198.19.221.254198.19.221.255510
240198.19.222.0/23198.19.222.1 to 198.19.223.254198.19.223.255510
241198.19.224.0/23198.19.224.1 to 198.19.225.254198.19.225.255510
242198.19.226.0/23198.19.226.1 to 198.19.227.254198.19.227.255510
243198.19.228.0/23198.19.228.1 to 198.19.229.254198.19.229.255510
244198.19.230.0/23198.19.230.1 to 198.19.231.254198.19.231.255510
245198.19.232.0/23198.19.232.1 to 198.19.233.254198.19.233.255510
246198.19.234.0/23198.19.234.1 to 198.19.235.254198.19.235.255510
247198.19.236.0/23198.19.236.1 to 198.19.237.254198.19.237.255510
248198.19.238.0/23198.19.238.1 to 198.19.239.254198.19.239.255510
249198.19.240.0/23198.19.240.1 to 198.19.241.254198.19.241.255510
250198.19.242.0/23198.19.242.1 to 198.19.243.254198.19.243.255510
251198.19.244.0/23198.19.244.1 to 198.19.245.254198.19.245.255510
252198.19.246.0/23198.19.246.1 to 198.19.247.254198.19.247.255510
253198.19.248.0/23198.19.248.1 to 198.19.249.254198.19.249.255510
254198.19.250.0/23198.19.250.1 to 198.19.251.254198.19.251.255510
255198.19.252.0/23198.19.252.1 to 198.19.253.254198.19.253.255510
256198.19.254.0/23198.19.254.1 to 198.19.255.254198.19.255.255510

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.