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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.

Network192.0.0.0/3
Usable hosts536,870,910
Subnet mask224.0.0.0
Addresses536,870,912
Network address
192.0.0.0
Broadcast address
223.255.255.255
First usable
192.0.0.1
Last usable
223.255.255.254
Usable hosts
536,870,910 (536,870,912 less the network and broadcast addresses)
Subnet mask
224.0.0.0
Wildcard mask
31.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/3
Type
Public public
Old class
C (default /24)
As numbers
Hex C0000000 · Integer 3221225472 to 3758096383
Reverse DNS zones
192.in-addr.arpa
193.in-addr.arpa
194.in-addr.arpa
195.in-addr.arpa
196.in-addr.arpa
197.in-addr.arpa
198.in-addr.arpa
199.in-addr.arpa
200.in-addr.arpa
201.in-addr.arpa
202.in-addr.arpa
203.in-addr.arpa
204.in-addr.arpa
205.in-addr.arpa
206.in-addr.arpa
207.in-addr.arpa
and 16 more
/3 is not on a 8-bit boundary, so it takes 32 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11000000.00000000.00000000.00000000192.0.0.0
Subnet mask11100000.00000000.00000000.00000000224.0.0.0
Network11000000.00000000.00000000.00000000192.0.0.0
Broadcast11011111.11111111.11111111.11111111223.255.255.255
Split into smaller subnets/12
/4 (2)/5 (4)/6 (8)/7 (16)/8 (32)/9 (64)/10 (128)/11 (256)/12 (512)/13 (1,024)/14 (2,048)/15 (4,096)

192.0.0.0/3 makes 512 subnets of /12; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1192.0.0.0/12192.0.0.1 to 192.15.255.254192.15.255.2551,048,574
2192.16.0.0/12192.16.0.1 to 192.31.255.254192.31.255.2551,048,574
3192.32.0.0/12192.32.0.1 to 192.47.255.254192.47.255.2551,048,574
4192.48.0.0/12192.48.0.1 to 192.63.255.254192.63.255.2551,048,574
5192.64.0.0/12192.64.0.1 to 192.79.255.254192.79.255.2551,048,574
6192.80.0.0/12192.80.0.1 to 192.95.255.254192.95.255.2551,048,574
7192.96.0.0/12192.96.0.1 to 192.111.255.254192.111.255.2551,048,574
8192.112.0.0/12192.112.0.1 to 192.127.255.254192.127.255.2551,048,574
9192.128.0.0/12192.128.0.1 to 192.143.255.254192.143.255.2551,048,574
10192.144.0.0/12192.144.0.1 to 192.159.255.254192.159.255.2551,048,574
11192.160.0.0/12192.160.0.1 to 192.175.255.254192.175.255.2551,048,574
12192.176.0.0/12192.176.0.1 to 192.191.255.254192.191.255.2551,048,574
13192.192.0.0/12192.192.0.1 to 192.207.255.254192.207.255.2551,048,574
14192.208.0.0/12192.208.0.1 to 192.223.255.254192.223.255.2551,048,574
15192.224.0.0/12192.224.0.1 to 192.239.255.254192.239.255.2551,048,574
16192.240.0.0/12192.240.0.1 to 192.255.255.254192.255.255.2551,048,574
17193.0.0.0/12193.0.0.1 to 193.15.255.254193.15.255.2551,048,574
18193.16.0.0/12193.16.0.1 to 193.31.255.254193.31.255.2551,048,574
19193.32.0.0/12193.32.0.1 to 193.47.255.254193.47.255.2551,048,574
20193.48.0.0/12193.48.0.1 to 193.63.255.254193.63.255.2551,048,574
21193.64.0.0/12193.64.0.1 to 193.79.255.254193.79.255.2551,048,574
22193.80.0.0/12193.80.0.1 to 193.95.255.254193.95.255.2551,048,574
23193.96.0.0/12193.96.0.1 to 193.111.255.254193.111.255.2551,048,574
24193.112.0.0/12193.112.0.1 to 193.127.255.254193.127.255.2551,048,574
25193.128.0.0/12193.128.0.1 to 193.143.255.254193.143.255.2551,048,574
26193.144.0.0/12193.144.0.1 to 193.159.255.254193.159.255.2551,048,574
27193.160.0.0/12193.160.0.1 to 193.175.255.254193.175.255.2551,048,574
28193.176.0.0/12193.176.0.1 to 193.191.255.254193.191.255.2551,048,574
29193.192.0.0/12193.192.0.1 to 193.207.255.254193.207.255.2551,048,574
30193.208.0.0/12193.208.0.1 to 193.223.255.254193.223.255.2551,048,574
31193.224.0.0/12193.224.0.1 to 193.239.255.254193.239.255.2551,048,574
32193.240.0.0/12193.240.0.1 to 193.255.255.254193.255.255.2551,048,574
33194.0.0.0/12194.0.0.1 to 194.15.255.254194.15.255.2551,048,574
34194.16.0.0/12194.16.0.1 to 194.31.255.254194.31.255.2551,048,574
35194.32.0.0/12194.32.0.1 to 194.47.255.254194.47.255.2551,048,574
36194.48.0.0/12194.48.0.1 to 194.63.255.254194.63.255.2551,048,574
37194.64.0.0/12194.64.0.1 to 194.79.255.254194.79.255.2551,048,574
38194.80.0.0/12194.80.0.1 to 194.95.255.254194.95.255.2551,048,574
39194.96.0.0/12194.96.0.1 to 194.111.255.254194.111.255.2551,048,574
40194.112.0.0/12194.112.0.1 to 194.127.255.254194.127.255.2551,048,574
41194.128.0.0/12194.128.0.1 to 194.143.255.254194.143.255.2551,048,574
42194.144.0.0/12194.144.0.1 to 194.159.255.254194.159.255.2551,048,574
43194.160.0.0/12194.160.0.1 to 194.175.255.254194.175.255.2551,048,574
44194.176.0.0/12194.176.0.1 to 194.191.255.254194.191.255.2551,048,574
45194.192.0.0/12194.192.0.1 to 194.207.255.254194.207.255.2551,048,574
46194.208.0.0/12194.208.0.1 to 194.223.255.254194.223.255.2551,048,574
47194.224.0.0/12194.224.0.1 to 194.239.255.254194.239.255.2551,048,574
48194.240.0.0/12194.240.0.1 to 194.255.255.254194.255.255.2551,048,574
49195.0.0.0/12195.0.0.1 to 195.15.255.254195.15.255.2551,048,574
50195.16.0.0/12195.16.0.1 to 195.31.255.254195.31.255.2551,048,574
51195.32.0.0/12195.32.0.1 to 195.47.255.254195.47.255.2551,048,574
52195.48.0.0/12195.48.0.1 to 195.63.255.254195.63.255.2551,048,574
53195.64.0.0/12195.64.0.1 to 195.79.255.254195.79.255.2551,048,574
54195.80.0.0/12195.80.0.1 to 195.95.255.254195.95.255.2551,048,574
55195.96.0.0/12195.96.0.1 to 195.111.255.254195.111.255.2551,048,574
56195.112.0.0/12195.112.0.1 to 195.127.255.254195.127.255.2551,048,574
57195.128.0.0/12195.128.0.1 to 195.143.255.254195.143.255.2551,048,574
58195.144.0.0/12195.144.0.1 to 195.159.255.254195.159.255.2551,048,574
59195.160.0.0/12195.160.0.1 to 195.175.255.254195.175.255.2551,048,574
60195.176.0.0/12195.176.0.1 to 195.191.255.254195.191.255.2551,048,574
61195.192.0.0/12195.192.0.1 to 195.207.255.254195.207.255.2551,048,574
62195.208.0.0/12195.208.0.1 to 195.223.255.254195.223.255.2551,048,574
63195.224.0.0/12195.224.0.1 to 195.239.255.254195.239.255.2551,048,574
64195.240.0.0/12195.240.0.1 to 195.255.255.254195.255.255.2551,048,574
65196.0.0.0/12196.0.0.1 to 196.15.255.254196.15.255.2551,048,574
66196.16.0.0/12196.16.0.1 to 196.31.255.254196.31.255.2551,048,574
67196.32.0.0/12196.32.0.1 to 196.47.255.254196.47.255.2551,048,574
68196.48.0.0/12196.48.0.1 to 196.63.255.254196.63.255.2551,048,574
69196.64.0.0/12196.64.0.1 to 196.79.255.254196.79.255.2551,048,574
70196.80.0.0/12196.80.0.1 to 196.95.255.254196.95.255.2551,048,574
71196.96.0.0/12196.96.0.1 to 196.111.255.254196.111.255.2551,048,574
72196.112.0.0/12196.112.0.1 to 196.127.255.254196.127.255.2551,048,574
73196.128.0.0/12196.128.0.1 to 196.143.255.254196.143.255.2551,048,574
74196.144.0.0/12196.144.0.1 to 196.159.255.254196.159.255.2551,048,574
75196.160.0.0/12196.160.0.1 to 196.175.255.254196.175.255.2551,048,574
76196.176.0.0/12196.176.0.1 to 196.191.255.254196.191.255.2551,048,574
77196.192.0.0/12196.192.0.1 to 196.207.255.254196.207.255.2551,048,574
78196.208.0.0/12196.208.0.1 to 196.223.255.254196.223.255.2551,048,574
79196.224.0.0/12196.224.0.1 to 196.239.255.254196.239.255.2551,048,574
80196.240.0.0/12196.240.0.1 to 196.255.255.254196.255.255.2551,048,574
81197.0.0.0/12197.0.0.1 to 197.15.255.254197.15.255.2551,048,574
82197.16.0.0/12197.16.0.1 to 197.31.255.254197.31.255.2551,048,574
83197.32.0.0/12197.32.0.1 to 197.47.255.254197.47.255.2551,048,574
84197.48.0.0/12197.48.0.1 to 197.63.255.254197.63.255.2551,048,574
85197.64.0.0/12197.64.0.1 to 197.79.255.254197.79.255.2551,048,574
86197.80.0.0/12197.80.0.1 to 197.95.255.254197.95.255.2551,048,574
87197.96.0.0/12197.96.0.1 to 197.111.255.254197.111.255.2551,048,574
88197.112.0.0/12197.112.0.1 to 197.127.255.254197.127.255.2551,048,574
89197.128.0.0/12197.128.0.1 to 197.143.255.254197.143.255.2551,048,574
90197.144.0.0/12197.144.0.1 to 197.159.255.254197.159.255.2551,048,574
91197.160.0.0/12197.160.0.1 to 197.175.255.254197.175.255.2551,048,574
92197.176.0.0/12197.176.0.1 to 197.191.255.254197.191.255.2551,048,574
93197.192.0.0/12197.192.0.1 to 197.207.255.254197.207.255.2551,048,574
94197.208.0.0/12197.208.0.1 to 197.223.255.254197.223.255.2551,048,574
95197.224.0.0/12197.224.0.1 to 197.239.255.254197.239.255.2551,048,574
96197.240.0.0/12197.240.0.1 to 197.255.255.254197.255.255.2551,048,574
97198.0.0.0/12198.0.0.1 to 198.15.255.254198.15.255.2551,048,574
98198.16.0.0/12198.16.0.1 to 198.31.255.254198.31.255.2551,048,574
99198.32.0.0/12198.32.0.1 to 198.47.255.254198.47.255.2551,048,574
100198.48.0.0/12198.48.0.1 to 198.63.255.254198.63.255.2551,048,574
101198.64.0.0/12198.64.0.1 to 198.79.255.254198.79.255.2551,048,574
102198.80.0.0/12198.80.0.1 to 198.95.255.254198.95.255.2551,048,574
103198.96.0.0/12198.96.0.1 to 198.111.255.254198.111.255.2551,048,574
104198.112.0.0/12198.112.0.1 to 198.127.255.254198.127.255.2551,048,574
105198.128.0.0/12198.128.0.1 to 198.143.255.254198.143.255.2551,048,574
106198.144.0.0/12198.144.0.1 to 198.159.255.254198.159.255.2551,048,574
107198.160.0.0/12198.160.0.1 to 198.175.255.254198.175.255.2551,048,574
108198.176.0.0/12198.176.0.1 to 198.191.255.254198.191.255.2551,048,574
109198.192.0.0/12198.192.0.1 to 198.207.255.254198.207.255.2551,048,574
110198.208.0.0/12198.208.0.1 to 198.223.255.254198.223.255.2551,048,574
111198.224.0.0/12198.224.0.1 to 198.239.255.254198.239.255.2551,048,574
112198.240.0.0/12198.240.0.1 to 198.255.255.254198.255.255.2551,048,574
113199.0.0.0/12199.0.0.1 to 199.15.255.254199.15.255.2551,048,574
114199.16.0.0/12199.16.0.1 to 199.31.255.254199.31.255.2551,048,574
115199.32.0.0/12199.32.0.1 to 199.47.255.254199.47.255.2551,048,574
116199.48.0.0/12199.48.0.1 to 199.63.255.254199.63.255.2551,048,574
117199.64.0.0/12199.64.0.1 to 199.79.255.254199.79.255.2551,048,574
118199.80.0.0/12199.80.0.1 to 199.95.255.254199.95.255.2551,048,574
119199.96.0.0/12199.96.0.1 to 199.111.255.254199.111.255.2551,048,574
120199.112.0.0/12199.112.0.1 to 199.127.255.254199.127.255.2551,048,574
121199.128.0.0/12199.128.0.1 to 199.143.255.254199.143.255.2551,048,574
122199.144.0.0/12199.144.0.1 to 199.159.255.254199.159.255.2551,048,574
123199.160.0.0/12199.160.0.1 to 199.175.255.254199.175.255.2551,048,574
124199.176.0.0/12199.176.0.1 to 199.191.255.254199.191.255.2551,048,574
125199.192.0.0/12199.192.0.1 to 199.207.255.254199.207.255.2551,048,574
126199.208.0.0/12199.208.0.1 to 199.223.255.254199.223.255.2551,048,574
127199.224.0.0/12199.224.0.1 to 199.239.255.254199.239.255.2551,048,574
128199.240.0.0/12199.240.0.1 to 199.255.255.254199.255.255.2551,048,574
129200.0.0.0/12200.0.0.1 to 200.15.255.254200.15.255.2551,048,574
130200.16.0.0/12200.16.0.1 to 200.31.255.254200.31.255.2551,048,574
131200.32.0.0/12200.32.0.1 to 200.47.255.254200.47.255.2551,048,574
132200.48.0.0/12200.48.0.1 to 200.63.255.254200.63.255.2551,048,574
133200.64.0.0/12200.64.0.1 to 200.79.255.254200.79.255.2551,048,574
134200.80.0.0/12200.80.0.1 to 200.95.255.254200.95.255.2551,048,574
135200.96.0.0/12200.96.0.1 to 200.111.255.254200.111.255.2551,048,574
136200.112.0.0/12200.112.0.1 to 200.127.255.254200.127.255.2551,048,574
137200.128.0.0/12200.128.0.1 to 200.143.255.254200.143.255.2551,048,574
138200.144.0.0/12200.144.0.1 to 200.159.255.254200.159.255.2551,048,574
139200.160.0.0/12200.160.0.1 to 200.175.255.254200.175.255.2551,048,574
140200.176.0.0/12200.176.0.1 to 200.191.255.254200.191.255.2551,048,574
141200.192.0.0/12200.192.0.1 to 200.207.255.254200.207.255.2551,048,574
142200.208.0.0/12200.208.0.1 to 200.223.255.254200.223.255.2551,048,574
143200.224.0.0/12200.224.0.1 to 200.239.255.254200.239.255.2551,048,574
144200.240.0.0/12200.240.0.1 to 200.255.255.254200.255.255.2551,048,574
145201.0.0.0/12201.0.0.1 to 201.15.255.254201.15.255.2551,048,574
146201.16.0.0/12201.16.0.1 to 201.31.255.254201.31.255.2551,048,574
147201.32.0.0/12201.32.0.1 to 201.47.255.254201.47.255.2551,048,574
148201.48.0.0/12201.48.0.1 to 201.63.255.254201.63.255.2551,048,574
149201.64.0.0/12201.64.0.1 to 201.79.255.254201.79.255.2551,048,574
150201.80.0.0/12201.80.0.1 to 201.95.255.254201.95.255.2551,048,574
151201.96.0.0/12201.96.0.1 to 201.111.255.254201.111.255.2551,048,574
152201.112.0.0/12201.112.0.1 to 201.127.255.254201.127.255.2551,048,574
153201.128.0.0/12201.128.0.1 to 201.143.255.254201.143.255.2551,048,574
154201.144.0.0/12201.144.0.1 to 201.159.255.254201.159.255.2551,048,574
155201.160.0.0/12201.160.0.1 to 201.175.255.254201.175.255.2551,048,574
156201.176.0.0/12201.176.0.1 to 201.191.255.254201.191.255.2551,048,574
157201.192.0.0/12201.192.0.1 to 201.207.255.254201.207.255.2551,048,574
158201.208.0.0/12201.208.0.1 to 201.223.255.254201.223.255.2551,048,574
159201.224.0.0/12201.224.0.1 to 201.239.255.254201.239.255.2551,048,574
160201.240.0.0/12201.240.0.1 to 201.255.255.254201.255.255.2551,048,574
161202.0.0.0/12202.0.0.1 to 202.15.255.254202.15.255.2551,048,574
162202.16.0.0/12202.16.0.1 to 202.31.255.254202.31.255.2551,048,574
163202.32.0.0/12202.32.0.1 to 202.47.255.254202.47.255.2551,048,574
164202.48.0.0/12202.48.0.1 to 202.63.255.254202.63.255.2551,048,574
165202.64.0.0/12202.64.0.1 to 202.79.255.254202.79.255.2551,048,574
166202.80.0.0/12202.80.0.1 to 202.95.255.254202.95.255.2551,048,574
167202.96.0.0/12202.96.0.1 to 202.111.255.254202.111.255.2551,048,574
168202.112.0.0/12202.112.0.1 to 202.127.255.254202.127.255.2551,048,574
169202.128.0.0/12202.128.0.1 to 202.143.255.254202.143.255.2551,048,574
170202.144.0.0/12202.144.0.1 to 202.159.255.254202.159.255.2551,048,574
171202.160.0.0/12202.160.0.1 to 202.175.255.254202.175.255.2551,048,574
172202.176.0.0/12202.176.0.1 to 202.191.255.254202.191.255.2551,048,574
173202.192.0.0/12202.192.0.1 to 202.207.255.254202.207.255.2551,048,574
174202.208.0.0/12202.208.0.1 to 202.223.255.254202.223.255.2551,048,574
175202.224.0.0/12202.224.0.1 to 202.239.255.254202.239.255.2551,048,574
176202.240.0.0/12202.240.0.1 to 202.255.255.254202.255.255.2551,048,574
177203.0.0.0/12203.0.0.1 to 203.15.255.254203.15.255.2551,048,574
178203.16.0.0/12203.16.0.1 to 203.31.255.254203.31.255.2551,048,574
179203.32.0.0/12203.32.0.1 to 203.47.255.254203.47.255.2551,048,574
180203.48.0.0/12203.48.0.1 to 203.63.255.254203.63.255.2551,048,574
181203.64.0.0/12203.64.0.1 to 203.79.255.254203.79.255.2551,048,574
182203.80.0.0/12203.80.0.1 to 203.95.255.254203.95.255.2551,048,574
183203.96.0.0/12203.96.0.1 to 203.111.255.254203.111.255.2551,048,574
184203.112.0.0/12203.112.0.1 to 203.127.255.254203.127.255.2551,048,574
185203.128.0.0/12203.128.0.1 to 203.143.255.254203.143.255.2551,048,574
186203.144.0.0/12203.144.0.1 to 203.159.255.254203.159.255.2551,048,574
187203.160.0.0/12203.160.0.1 to 203.175.255.254203.175.255.2551,048,574
188203.176.0.0/12203.176.0.1 to 203.191.255.254203.191.255.2551,048,574
189203.192.0.0/12203.192.0.1 to 203.207.255.254203.207.255.2551,048,574
190203.208.0.0/12203.208.0.1 to 203.223.255.254203.223.255.2551,048,574
191203.224.0.0/12203.224.0.1 to 203.239.255.254203.239.255.2551,048,574
192203.240.0.0/12203.240.0.1 to 203.255.255.254203.255.255.2551,048,574
193204.0.0.0/12204.0.0.1 to 204.15.255.254204.15.255.2551,048,574
194204.16.0.0/12204.16.0.1 to 204.31.255.254204.31.255.2551,048,574
195204.32.0.0/12204.32.0.1 to 204.47.255.254204.47.255.2551,048,574
196204.48.0.0/12204.48.0.1 to 204.63.255.254204.63.255.2551,048,574
197204.64.0.0/12204.64.0.1 to 204.79.255.254204.79.255.2551,048,574
198204.80.0.0/12204.80.0.1 to 204.95.255.254204.95.255.2551,048,574
199204.96.0.0/12204.96.0.1 to 204.111.255.254204.111.255.2551,048,574
200204.112.0.0/12204.112.0.1 to 204.127.255.254204.127.255.2551,048,574
201204.128.0.0/12204.128.0.1 to 204.143.255.254204.143.255.2551,048,574
202204.144.0.0/12204.144.0.1 to 204.159.255.254204.159.255.2551,048,574
203204.160.0.0/12204.160.0.1 to 204.175.255.254204.175.255.2551,048,574
204204.176.0.0/12204.176.0.1 to 204.191.255.254204.191.255.2551,048,574
205204.192.0.0/12204.192.0.1 to 204.207.255.254204.207.255.2551,048,574
206204.208.0.0/12204.208.0.1 to 204.223.255.254204.223.255.2551,048,574
207204.224.0.0/12204.224.0.1 to 204.239.255.254204.239.255.2551,048,574
208204.240.0.0/12204.240.0.1 to 204.255.255.254204.255.255.2551,048,574
209205.0.0.0/12205.0.0.1 to 205.15.255.254205.15.255.2551,048,574
210205.16.0.0/12205.16.0.1 to 205.31.255.254205.31.255.2551,048,574
211205.32.0.0/12205.32.0.1 to 205.47.255.254205.47.255.2551,048,574
212205.48.0.0/12205.48.0.1 to 205.63.255.254205.63.255.2551,048,574
213205.64.0.0/12205.64.0.1 to 205.79.255.254205.79.255.2551,048,574
214205.80.0.0/12205.80.0.1 to 205.95.255.254205.95.255.2551,048,574
215205.96.0.0/12205.96.0.1 to 205.111.255.254205.111.255.2551,048,574
216205.112.0.0/12205.112.0.1 to 205.127.255.254205.127.255.2551,048,574
217205.128.0.0/12205.128.0.1 to 205.143.255.254205.143.255.2551,048,574
218205.144.0.0/12205.144.0.1 to 205.159.255.254205.159.255.2551,048,574
219205.160.0.0/12205.160.0.1 to 205.175.255.254205.175.255.2551,048,574
220205.176.0.0/12205.176.0.1 to 205.191.255.254205.191.255.2551,048,574
221205.192.0.0/12205.192.0.1 to 205.207.255.254205.207.255.2551,048,574
222205.208.0.0/12205.208.0.1 to 205.223.255.254205.223.255.2551,048,574
223205.224.0.0/12205.224.0.1 to 205.239.255.254205.239.255.2551,048,574
224205.240.0.0/12205.240.0.1 to 205.255.255.254205.255.255.2551,048,574
225206.0.0.0/12206.0.0.1 to 206.15.255.254206.15.255.2551,048,574
226206.16.0.0/12206.16.0.1 to 206.31.255.254206.31.255.2551,048,574
227206.32.0.0/12206.32.0.1 to 206.47.255.254206.47.255.2551,048,574
228206.48.0.0/12206.48.0.1 to 206.63.255.254206.63.255.2551,048,574
229206.64.0.0/12206.64.0.1 to 206.79.255.254206.79.255.2551,048,574
230206.80.0.0/12206.80.0.1 to 206.95.255.254206.95.255.2551,048,574
231206.96.0.0/12206.96.0.1 to 206.111.255.254206.111.255.2551,048,574
232206.112.0.0/12206.112.0.1 to 206.127.255.254206.127.255.2551,048,574
233206.128.0.0/12206.128.0.1 to 206.143.255.254206.143.255.2551,048,574
234206.144.0.0/12206.144.0.1 to 206.159.255.254206.159.255.2551,048,574
235206.160.0.0/12206.160.0.1 to 206.175.255.254206.175.255.2551,048,574
236206.176.0.0/12206.176.0.1 to 206.191.255.254206.191.255.2551,048,574
237206.192.0.0/12206.192.0.1 to 206.207.255.254206.207.255.2551,048,574
238206.208.0.0/12206.208.0.1 to 206.223.255.254206.223.255.2551,048,574
239206.224.0.0/12206.224.0.1 to 206.239.255.254206.239.255.2551,048,574
240206.240.0.0/12206.240.0.1 to 206.255.255.254206.255.255.2551,048,574
241207.0.0.0/12207.0.0.1 to 207.15.255.254207.15.255.2551,048,574
242207.16.0.0/12207.16.0.1 to 207.31.255.254207.31.255.2551,048,574
243207.32.0.0/12207.32.0.1 to 207.47.255.254207.47.255.2551,048,574
244207.48.0.0/12207.48.0.1 to 207.63.255.254207.63.255.2551,048,574
245207.64.0.0/12207.64.0.1 to 207.79.255.254207.79.255.2551,048,574
246207.80.0.0/12207.80.0.1 to 207.95.255.254207.95.255.2551,048,574
247207.96.0.0/12207.96.0.1 to 207.111.255.254207.111.255.2551,048,574
248207.112.0.0/12207.112.0.1 to 207.127.255.254207.127.255.2551,048,574
249207.128.0.0/12207.128.0.1 to 207.143.255.254207.143.255.2551,048,574
250207.144.0.0/12207.144.0.1 to 207.159.255.254207.159.255.2551,048,574
251207.160.0.0/12207.160.0.1 to 207.175.255.254207.175.255.2551,048,574
252207.176.0.0/12207.176.0.1 to 207.191.255.254207.191.255.2551,048,574
253207.192.0.0/12207.192.0.1 to 207.207.255.254207.207.255.2551,048,574
254207.208.0.0/12207.208.0.1 to 207.223.255.254207.223.255.2551,048,574
255207.224.0.0/12207.224.0.1 to 207.239.255.254207.239.255.2551,048,574
256207.240.0.0/12207.240.0.1 to 207.255.255.254207.255.255.2551,048,574

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.