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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/24
/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 512 subnets of /24; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1198.18.0.0/24198.18.0.1 to 198.18.0.254198.18.0.255254
2198.18.1.0/24198.18.1.1 to 198.18.1.254198.18.1.255254
3198.18.2.0/24198.18.2.1 to 198.18.2.254198.18.2.255254
4198.18.3.0/24198.18.3.1 to 198.18.3.254198.18.3.255254
5198.18.4.0/24198.18.4.1 to 198.18.4.254198.18.4.255254
6198.18.5.0/24198.18.5.1 to 198.18.5.254198.18.5.255254
7198.18.6.0/24198.18.6.1 to 198.18.6.254198.18.6.255254
8198.18.7.0/24198.18.7.1 to 198.18.7.254198.18.7.255254
9198.18.8.0/24198.18.8.1 to 198.18.8.254198.18.8.255254
10198.18.9.0/24198.18.9.1 to 198.18.9.254198.18.9.255254
11198.18.10.0/24198.18.10.1 to 198.18.10.254198.18.10.255254
12198.18.11.0/24198.18.11.1 to 198.18.11.254198.18.11.255254
13198.18.12.0/24198.18.12.1 to 198.18.12.254198.18.12.255254
14198.18.13.0/24198.18.13.1 to 198.18.13.254198.18.13.255254
15198.18.14.0/24198.18.14.1 to 198.18.14.254198.18.14.255254
16198.18.15.0/24198.18.15.1 to 198.18.15.254198.18.15.255254
17198.18.16.0/24198.18.16.1 to 198.18.16.254198.18.16.255254
18198.18.17.0/24198.18.17.1 to 198.18.17.254198.18.17.255254
19198.18.18.0/24198.18.18.1 to 198.18.18.254198.18.18.255254
20198.18.19.0/24198.18.19.1 to 198.18.19.254198.18.19.255254
21198.18.20.0/24198.18.20.1 to 198.18.20.254198.18.20.255254
22198.18.21.0/24198.18.21.1 to 198.18.21.254198.18.21.255254
23198.18.22.0/24198.18.22.1 to 198.18.22.254198.18.22.255254
24198.18.23.0/24198.18.23.1 to 198.18.23.254198.18.23.255254
25198.18.24.0/24198.18.24.1 to 198.18.24.254198.18.24.255254
26198.18.25.0/24198.18.25.1 to 198.18.25.254198.18.25.255254
27198.18.26.0/24198.18.26.1 to 198.18.26.254198.18.26.255254
28198.18.27.0/24198.18.27.1 to 198.18.27.254198.18.27.255254
29198.18.28.0/24198.18.28.1 to 198.18.28.254198.18.28.255254
30198.18.29.0/24198.18.29.1 to 198.18.29.254198.18.29.255254
31198.18.30.0/24198.18.30.1 to 198.18.30.254198.18.30.255254
32198.18.31.0/24198.18.31.1 to 198.18.31.254198.18.31.255254
33198.18.32.0/24198.18.32.1 to 198.18.32.254198.18.32.255254
34198.18.33.0/24198.18.33.1 to 198.18.33.254198.18.33.255254
35198.18.34.0/24198.18.34.1 to 198.18.34.254198.18.34.255254
36198.18.35.0/24198.18.35.1 to 198.18.35.254198.18.35.255254
37198.18.36.0/24198.18.36.1 to 198.18.36.254198.18.36.255254
38198.18.37.0/24198.18.37.1 to 198.18.37.254198.18.37.255254
39198.18.38.0/24198.18.38.1 to 198.18.38.254198.18.38.255254
40198.18.39.0/24198.18.39.1 to 198.18.39.254198.18.39.255254
41198.18.40.0/24198.18.40.1 to 198.18.40.254198.18.40.255254
42198.18.41.0/24198.18.41.1 to 198.18.41.254198.18.41.255254
43198.18.42.0/24198.18.42.1 to 198.18.42.254198.18.42.255254
44198.18.43.0/24198.18.43.1 to 198.18.43.254198.18.43.255254
45198.18.44.0/24198.18.44.1 to 198.18.44.254198.18.44.255254
46198.18.45.0/24198.18.45.1 to 198.18.45.254198.18.45.255254
47198.18.46.0/24198.18.46.1 to 198.18.46.254198.18.46.255254
48198.18.47.0/24198.18.47.1 to 198.18.47.254198.18.47.255254
49198.18.48.0/24198.18.48.1 to 198.18.48.254198.18.48.255254
50198.18.49.0/24198.18.49.1 to 198.18.49.254198.18.49.255254
51198.18.50.0/24198.18.50.1 to 198.18.50.254198.18.50.255254
52198.18.51.0/24198.18.51.1 to 198.18.51.254198.18.51.255254
53198.18.52.0/24198.18.52.1 to 198.18.52.254198.18.52.255254
54198.18.53.0/24198.18.53.1 to 198.18.53.254198.18.53.255254
55198.18.54.0/24198.18.54.1 to 198.18.54.254198.18.54.255254
56198.18.55.0/24198.18.55.1 to 198.18.55.254198.18.55.255254
57198.18.56.0/24198.18.56.1 to 198.18.56.254198.18.56.255254
58198.18.57.0/24198.18.57.1 to 198.18.57.254198.18.57.255254
59198.18.58.0/24198.18.58.1 to 198.18.58.254198.18.58.255254
60198.18.59.0/24198.18.59.1 to 198.18.59.254198.18.59.255254
61198.18.60.0/24198.18.60.1 to 198.18.60.254198.18.60.255254
62198.18.61.0/24198.18.61.1 to 198.18.61.254198.18.61.255254
63198.18.62.0/24198.18.62.1 to 198.18.62.254198.18.62.255254
64198.18.63.0/24198.18.63.1 to 198.18.63.254198.18.63.255254
65198.18.64.0/24198.18.64.1 to 198.18.64.254198.18.64.255254
66198.18.65.0/24198.18.65.1 to 198.18.65.254198.18.65.255254
67198.18.66.0/24198.18.66.1 to 198.18.66.254198.18.66.255254
68198.18.67.0/24198.18.67.1 to 198.18.67.254198.18.67.255254
69198.18.68.0/24198.18.68.1 to 198.18.68.254198.18.68.255254
70198.18.69.0/24198.18.69.1 to 198.18.69.254198.18.69.255254
71198.18.70.0/24198.18.70.1 to 198.18.70.254198.18.70.255254
72198.18.71.0/24198.18.71.1 to 198.18.71.254198.18.71.255254
73198.18.72.0/24198.18.72.1 to 198.18.72.254198.18.72.255254
74198.18.73.0/24198.18.73.1 to 198.18.73.254198.18.73.255254
75198.18.74.0/24198.18.74.1 to 198.18.74.254198.18.74.255254
76198.18.75.0/24198.18.75.1 to 198.18.75.254198.18.75.255254
77198.18.76.0/24198.18.76.1 to 198.18.76.254198.18.76.255254
78198.18.77.0/24198.18.77.1 to 198.18.77.254198.18.77.255254
79198.18.78.0/24198.18.78.1 to 198.18.78.254198.18.78.255254
80198.18.79.0/24198.18.79.1 to 198.18.79.254198.18.79.255254
81198.18.80.0/24198.18.80.1 to 198.18.80.254198.18.80.255254
82198.18.81.0/24198.18.81.1 to 198.18.81.254198.18.81.255254
83198.18.82.0/24198.18.82.1 to 198.18.82.254198.18.82.255254
84198.18.83.0/24198.18.83.1 to 198.18.83.254198.18.83.255254
85198.18.84.0/24198.18.84.1 to 198.18.84.254198.18.84.255254
86198.18.85.0/24198.18.85.1 to 198.18.85.254198.18.85.255254
87198.18.86.0/24198.18.86.1 to 198.18.86.254198.18.86.255254
88198.18.87.0/24198.18.87.1 to 198.18.87.254198.18.87.255254
89198.18.88.0/24198.18.88.1 to 198.18.88.254198.18.88.255254
90198.18.89.0/24198.18.89.1 to 198.18.89.254198.18.89.255254
91198.18.90.0/24198.18.90.1 to 198.18.90.254198.18.90.255254
92198.18.91.0/24198.18.91.1 to 198.18.91.254198.18.91.255254
93198.18.92.0/24198.18.92.1 to 198.18.92.254198.18.92.255254
94198.18.93.0/24198.18.93.1 to 198.18.93.254198.18.93.255254
95198.18.94.0/24198.18.94.1 to 198.18.94.254198.18.94.255254
96198.18.95.0/24198.18.95.1 to 198.18.95.254198.18.95.255254
97198.18.96.0/24198.18.96.1 to 198.18.96.254198.18.96.255254
98198.18.97.0/24198.18.97.1 to 198.18.97.254198.18.97.255254
99198.18.98.0/24198.18.98.1 to 198.18.98.254198.18.98.255254
100198.18.99.0/24198.18.99.1 to 198.18.99.254198.18.99.255254
101198.18.100.0/24198.18.100.1 to 198.18.100.254198.18.100.255254
102198.18.101.0/24198.18.101.1 to 198.18.101.254198.18.101.255254
103198.18.102.0/24198.18.102.1 to 198.18.102.254198.18.102.255254
104198.18.103.0/24198.18.103.1 to 198.18.103.254198.18.103.255254
105198.18.104.0/24198.18.104.1 to 198.18.104.254198.18.104.255254
106198.18.105.0/24198.18.105.1 to 198.18.105.254198.18.105.255254
107198.18.106.0/24198.18.106.1 to 198.18.106.254198.18.106.255254
108198.18.107.0/24198.18.107.1 to 198.18.107.254198.18.107.255254
109198.18.108.0/24198.18.108.1 to 198.18.108.254198.18.108.255254
110198.18.109.0/24198.18.109.1 to 198.18.109.254198.18.109.255254
111198.18.110.0/24198.18.110.1 to 198.18.110.254198.18.110.255254
112198.18.111.0/24198.18.111.1 to 198.18.111.254198.18.111.255254
113198.18.112.0/24198.18.112.1 to 198.18.112.254198.18.112.255254
114198.18.113.0/24198.18.113.1 to 198.18.113.254198.18.113.255254
115198.18.114.0/24198.18.114.1 to 198.18.114.254198.18.114.255254
116198.18.115.0/24198.18.115.1 to 198.18.115.254198.18.115.255254
117198.18.116.0/24198.18.116.1 to 198.18.116.254198.18.116.255254
118198.18.117.0/24198.18.117.1 to 198.18.117.254198.18.117.255254
119198.18.118.0/24198.18.118.1 to 198.18.118.254198.18.118.255254
120198.18.119.0/24198.18.119.1 to 198.18.119.254198.18.119.255254
121198.18.120.0/24198.18.120.1 to 198.18.120.254198.18.120.255254
122198.18.121.0/24198.18.121.1 to 198.18.121.254198.18.121.255254
123198.18.122.0/24198.18.122.1 to 198.18.122.254198.18.122.255254
124198.18.123.0/24198.18.123.1 to 198.18.123.254198.18.123.255254
125198.18.124.0/24198.18.124.1 to 198.18.124.254198.18.124.255254
126198.18.125.0/24198.18.125.1 to 198.18.125.254198.18.125.255254
127198.18.126.0/24198.18.126.1 to 198.18.126.254198.18.126.255254
128198.18.127.0/24198.18.127.1 to 198.18.127.254198.18.127.255254
129198.18.128.0/24198.18.128.1 to 198.18.128.254198.18.128.255254
130198.18.129.0/24198.18.129.1 to 198.18.129.254198.18.129.255254
131198.18.130.0/24198.18.130.1 to 198.18.130.254198.18.130.255254
132198.18.131.0/24198.18.131.1 to 198.18.131.254198.18.131.255254
133198.18.132.0/24198.18.132.1 to 198.18.132.254198.18.132.255254
134198.18.133.0/24198.18.133.1 to 198.18.133.254198.18.133.255254
135198.18.134.0/24198.18.134.1 to 198.18.134.254198.18.134.255254
136198.18.135.0/24198.18.135.1 to 198.18.135.254198.18.135.255254
137198.18.136.0/24198.18.136.1 to 198.18.136.254198.18.136.255254
138198.18.137.0/24198.18.137.1 to 198.18.137.254198.18.137.255254
139198.18.138.0/24198.18.138.1 to 198.18.138.254198.18.138.255254
140198.18.139.0/24198.18.139.1 to 198.18.139.254198.18.139.255254
141198.18.140.0/24198.18.140.1 to 198.18.140.254198.18.140.255254
142198.18.141.0/24198.18.141.1 to 198.18.141.254198.18.141.255254
143198.18.142.0/24198.18.142.1 to 198.18.142.254198.18.142.255254
144198.18.143.0/24198.18.143.1 to 198.18.143.254198.18.143.255254
145198.18.144.0/24198.18.144.1 to 198.18.144.254198.18.144.255254
146198.18.145.0/24198.18.145.1 to 198.18.145.254198.18.145.255254
147198.18.146.0/24198.18.146.1 to 198.18.146.254198.18.146.255254
148198.18.147.0/24198.18.147.1 to 198.18.147.254198.18.147.255254
149198.18.148.0/24198.18.148.1 to 198.18.148.254198.18.148.255254
150198.18.149.0/24198.18.149.1 to 198.18.149.254198.18.149.255254
151198.18.150.0/24198.18.150.1 to 198.18.150.254198.18.150.255254
152198.18.151.0/24198.18.151.1 to 198.18.151.254198.18.151.255254
153198.18.152.0/24198.18.152.1 to 198.18.152.254198.18.152.255254
154198.18.153.0/24198.18.153.1 to 198.18.153.254198.18.153.255254
155198.18.154.0/24198.18.154.1 to 198.18.154.254198.18.154.255254
156198.18.155.0/24198.18.155.1 to 198.18.155.254198.18.155.255254
157198.18.156.0/24198.18.156.1 to 198.18.156.254198.18.156.255254
158198.18.157.0/24198.18.157.1 to 198.18.157.254198.18.157.255254
159198.18.158.0/24198.18.158.1 to 198.18.158.254198.18.158.255254
160198.18.159.0/24198.18.159.1 to 198.18.159.254198.18.159.255254
161198.18.160.0/24198.18.160.1 to 198.18.160.254198.18.160.255254
162198.18.161.0/24198.18.161.1 to 198.18.161.254198.18.161.255254
163198.18.162.0/24198.18.162.1 to 198.18.162.254198.18.162.255254
164198.18.163.0/24198.18.163.1 to 198.18.163.254198.18.163.255254
165198.18.164.0/24198.18.164.1 to 198.18.164.254198.18.164.255254
166198.18.165.0/24198.18.165.1 to 198.18.165.254198.18.165.255254
167198.18.166.0/24198.18.166.1 to 198.18.166.254198.18.166.255254
168198.18.167.0/24198.18.167.1 to 198.18.167.254198.18.167.255254
169198.18.168.0/24198.18.168.1 to 198.18.168.254198.18.168.255254
170198.18.169.0/24198.18.169.1 to 198.18.169.254198.18.169.255254
171198.18.170.0/24198.18.170.1 to 198.18.170.254198.18.170.255254
172198.18.171.0/24198.18.171.1 to 198.18.171.254198.18.171.255254
173198.18.172.0/24198.18.172.1 to 198.18.172.254198.18.172.255254
174198.18.173.0/24198.18.173.1 to 198.18.173.254198.18.173.255254
175198.18.174.0/24198.18.174.1 to 198.18.174.254198.18.174.255254
176198.18.175.0/24198.18.175.1 to 198.18.175.254198.18.175.255254
177198.18.176.0/24198.18.176.1 to 198.18.176.254198.18.176.255254
178198.18.177.0/24198.18.177.1 to 198.18.177.254198.18.177.255254
179198.18.178.0/24198.18.178.1 to 198.18.178.254198.18.178.255254
180198.18.179.0/24198.18.179.1 to 198.18.179.254198.18.179.255254
181198.18.180.0/24198.18.180.1 to 198.18.180.254198.18.180.255254
182198.18.181.0/24198.18.181.1 to 198.18.181.254198.18.181.255254
183198.18.182.0/24198.18.182.1 to 198.18.182.254198.18.182.255254
184198.18.183.0/24198.18.183.1 to 198.18.183.254198.18.183.255254
185198.18.184.0/24198.18.184.1 to 198.18.184.254198.18.184.255254
186198.18.185.0/24198.18.185.1 to 198.18.185.254198.18.185.255254
187198.18.186.0/24198.18.186.1 to 198.18.186.254198.18.186.255254
188198.18.187.0/24198.18.187.1 to 198.18.187.254198.18.187.255254
189198.18.188.0/24198.18.188.1 to 198.18.188.254198.18.188.255254
190198.18.189.0/24198.18.189.1 to 198.18.189.254198.18.189.255254
191198.18.190.0/24198.18.190.1 to 198.18.190.254198.18.190.255254
192198.18.191.0/24198.18.191.1 to 198.18.191.254198.18.191.255254
193198.18.192.0/24198.18.192.1 to 198.18.192.254198.18.192.255254
194198.18.193.0/24198.18.193.1 to 198.18.193.254198.18.193.255254
195198.18.194.0/24198.18.194.1 to 198.18.194.254198.18.194.255254
196198.18.195.0/24198.18.195.1 to 198.18.195.254198.18.195.255254
197198.18.196.0/24198.18.196.1 to 198.18.196.254198.18.196.255254
198198.18.197.0/24198.18.197.1 to 198.18.197.254198.18.197.255254
199198.18.198.0/24198.18.198.1 to 198.18.198.254198.18.198.255254
200198.18.199.0/24198.18.199.1 to 198.18.199.254198.18.199.255254
201198.18.200.0/24198.18.200.1 to 198.18.200.254198.18.200.255254
202198.18.201.0/24198.18.201.1 to 198.18.201.254198.18.201.255254
203198.18.202.0/24198.18.202.1 to 198.18.202.254198.18.202.255254
204198.18.203.0/24198.18.203.1 to 198.18.203.254198.18.203.255254
205198.18.204.0/24198.18.204.1 to 198.18.204.254198.18.204.255254
206198.18.205.0/24198.18.205.1 to 198.18.205.254198.18.205.255254
207198.18.206.0/24198.18.206.1 to 198.18.206.254198.18.206.255254
208198.18.207.0/24198.18.207.1 to 198.18.207.254198.18.207.255254
209198.18.208.0/24198.18.208.1 to 198.18.208.254198.18.208.255254
210198.18.209.0/24198.18.209.1 to 198.18.209.254198.18.209.255254
211198.18.210.0/24198.18.210.1 to 198.18.210.254198.18.210.255254
212198.18.211.0/24198.18.211.1 to 198.18.211.254198.18.211.255254
213198.18.212.0/24198.18.212.1 to 198.18.212.254198.18.212.255254
214198.18.213.0/24198.18.213.1 to 198.18.213.254198.18.213.255254
215198.18.214.0/24198.18.214.1 to 198.18.214.254198.18.214.255254
216198.18.215.0/24198.18.215.1 to 198.18.215.254198.18.215.255254
217198.18.216.0/24198.18.216.1 to 198.18.216.254198.18.216.255254
218198.18.217.0/24198.18.217.1 to 198.18.217.254198.18.217.255254
219198.18.218.0/24198.18.218.1 to 198.18.218.254198.18.218.255254
220198.18.219.0/24198.18.219.1 to 198.18.219.254198.18.219.255254
221198.18.220.0/24198.18.220.1 to 198.18.220.254198.18.220.255254
222198.18.221.0/24198.18.221.1 to 198.18.221.254198.18.221.255254
223198.18.222.0/24198.18.222.1 to 198.18.222.254198.18.222.255254
224198.18.223.0/24198.18.223.1 to 198.18.223.254198.18.223.255254
225198.18.224.0/24198.18.224.1 to 198.18.224.254198.18.224.255254
226198.18.225.0/24198.18.225.1 to 198.18.225.254198.18.225.255254
227198.18.226.0/24198.18.226.1 to 198.18.226.254198.18.226.255254
228198.18.227.0/24198.18.227.1 to 198.18.227.254198.18.227.255254
229198.18.228.0/24198.18.228.1 to 198.18.228.254198.18.228.255254
230198.18.229.0/24198.18.229.1 to 198.18.229.254198.18.229.255254
231198.18.230.0/24198.18.230.1 to 198.18.230.254198.18.230.255254
232198.18.231.0/24198.18.231.1 to 198.18.231.254198.18.231.255254
233198.18.232.0/24198.18.232.1 to 198.18.232.254198.18.232.255254
234198.18.233.0/24198.18.233.1 to 198.18.233.254198.18.233.255254
235198.18.234.0/24198.18.234.1 to 198.18.234.254198.18.234.255254
236198.18.235.0/24198.18.235.1 to 198.18.235.254198.18.235.255254
237198.18.236.0/24198.18.236.1 to 198.18.236.254198.18.236.255254
238198.18.237.0/24198.18.237.1 to 198.18.237.254198.18.237.255254
239198.18.238.0/24198.18.238.1 to 198.18.238.254198.18.238.255254
240198.18.239.0/24198.18.239.1 to 198.18.239.254198.18.239.255254
241198.18.240.0/24198.18.240.1 to 198.18.240.254198.18.240.255254
242198.18.241.0/24198.18.241.1 to 198.18.241.254198.18.241.255254
243198.18.242.0/24198.18.242.1 to 198.18.242.254198.18.242.255254
244198.18.243.0/24198.18.243.1 to 198.18.243.254198.18.243.255254
245198.18.244.0/24198.18.244.1 to 198.18.244.254198.18.244.255254
246198.18.245.0/24198.18.245.1 to 198.18.245.254198.18.245.255254
247198.18.246.0/24198.18.246.1 to 198.18.246.254198.18.246.255254
248198.18.247.0/24198.18.247.1 to 198.18.247.254198.18.247.255254
249198.18.248.0/24198.18.248.1 to 198.18.248.254198.18.248.255254
250198.18.249.0/24198.18.249.1 to 198.18.249.254198.18.249.255254
251198.18.250.0/24198.18.250.1 to 198.18.250.254198.18.250.255254
252198.18.251.0/24198.18.251.1 to 198.18.251.254198.18.251.255254
253198.18.252.0/24198.18.252.1 to 198.18.252.254198.18.252.255254
254198.18.253.0/24198.18.253.1 to 198.18.253.254198.18.253.255254
255198.18.254.0/24198.18.254.1 to 198.18.254.254198.18.254.255254
256198.18.255.0/24198.18.255.1 to 198.18.255.254198.18.255.255254

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.