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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.

Network255.64.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
255.64.0.0
Broadcast address
255.127.255.255
First usable
255.64.0.1
Last usable
255.127.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex FF400000 · Integer 4282384384 to 4286578687
Reverse DNS zones
64.255.in-addr.arpa
65.255.in-addr.arpa
66.255.in-addr.arpa
67.255.in-addr.arpa
68.255.in-addr.arpa
69.255.in-addr.arpa
70.255.in-addr.arpa
71.255.in-addr.arpa
72.255.in-addr.arpa
73.255.in-addr.arpa
74.255.in-addr.arpa
75.255.in-addr.arpa
76.255.in-addr.arpa
77.255.in-addr.arpa
78.255.in-addr.arpa
79.255.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11111111.01000000.00000000.00000000255.64.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network11111111.01000000.00000000.00000000255.64.0.0
Broadcast11111111.01111111.11111111.11111111255.127.255.255
Split into smaller subnets/20
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

255.64.0.0/10 makes 1,024 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1255.64.0.0/20255.64.0.1 to 255.64.15.254255.64.15.2554,094
2255.64.16.0/20255.64.16.1 to 255.64.31.254255.64.31.2554,094
3255.64.32.0/20255.64.32.1 to 255.64.47.254255.64.47.2554,094
4255.64.48.0/20255.64.48.1 to 255.64.63.254255.64.63.2554,094
5255.64.64.0/20255.64.64.1 to 255.64.79.254255.64.79.2554,094
6255.64.80.0/20255.64.80.1 to 255.64.95.254255.64.95.2554,094
7255.64.96.0/20255.64.96.1 to 255.64.111.254255.64.111.2554,094
8255.64.112.0/20255.64.112.1 to 255.64.127.254255.64.127.2554,094
9255.64.128.0/20255.64.128.1 to 255.64.143.254255.64.143.2554,094
10255.64.144.0/20255.64.144.1 to 255.64.159.254255.64.159.2554,094
11255.64.160.0/20255.64.160.1 to 255.64.175.254255.64.175.2554,094
12255.64.176.0/20255.64.176.1 to 255.64.191.254255.64.191.2554,094
13255.64.192.0/20255.64.192.1 to 255.64.207.254255.64.207.2554,094
14255.64.208.0/20255.64.208.1 to 255.64.223.254255.64.223.2554,094
15255.64.224.0/20255.64.224.1 to 255.64.239.254255.64.239.2554,094
16255.64.240.0/20255.64.240.1 to 255.64.255.254255.64.255.2554,094
17255.65.0.0/20255.65.0.1 to 255.65.15.254255.65.15.2554,094
18255.65.16.0/20255.65.16.1 to 255.65.31.254255.65.31.2554,094
19255.65.32.0/20255.65.32.1 to 255.65.47.254255.65.47.2554,094
20255.65.48.0/20255.65.48.1 to 255.65.63.254255.65.63.2554,094
21255.65.64.0/20255.65.64.1 to 255.65.79.254255.65.79.2554,094
22255.65.80.0/20255.65.80.1 to 255.65.95.254255.65.95.2554,094
23255.65.96.0/20255.65.96.1 to 255.65.111.254255.65.111.2554,094
24255.65.112.0/20255.65.112.1 to 255.65.127.254255.65.127.2554,094
25255.65.128.0/20255.65.128.1 to 255.65.143.254255.65.143.2554,094
26255.65.144.0/20255.65.144.1 to 255.65.159.254255.65.159.2554,094
27255.65.160.0/20255.65.160.1 to 255.65.175.254255.65.175.2554,094
28255.65.176.0/20255.65.176.1 to 255.65.191.254255.65.191.2554,094
29255.65.192.0/20255.65.192.1 to 255.65.207.254255.65.207.2554,094
30255.65.208.0/20255.65.208.1 to 255.65.223.254255.65.223.2554,094
31255.65.224.0/20255.65.224.1 to 255.65.239.254255.65.239.2554,094
32255.65.240.0/20255.65.240.1 to 255.65.255.254255.65.255.2554,094
33255.66.0.0/20255.66.0.1 to 255.66.15.254255.66.15.2554,094
34255.66.16.0/20255.66.16.1 to 255.66.31.254255.66.31.2554,094
35255.66.32.0/20255.66.32.1 to 255.66.47.254255.66.47.2554,094
36255.66.48.0/20255.66.48.1 to 255.66.63.254255.66.63.2554,094
37255.66.64.0/20255.66.64.1 to 255.66.79.254255.66.79.2554,094
38255.66.80.0/20255.66.80.1 to 255.66.95.254255.66.95.2554,094
39255.66.96.0/20255.66.96.1 to 255.66.111.254255.66.111.2554,094
40255.66.112.0/20255.66.112.1 to 255.66.127.254255.66.127.2554,094
41255.66.128.0/20255.66.128.1 to 255.66.143.254255.66.143.2554,094
42255.66.144.0/20255.66.144.1 to 255.66.159.254255.66.159.2554,094
43255.66.160.0/20255.66.160.1 to 255.66.175.254255.66.175.2554,094
44255.66.176.0/20255.66.176.1 to 255.66.191.254255.66.191.2554,094
45255.66.192.0/20255.66.192.1 to 255.66.207.254255.66.207.2554,094
46255.66.208.0/20255.66.208.1 to 255.66.223.254255.66.223.2554,094
47255.66.224.0/20255.66.224.1 to 255.66.239.254255.66.239.2554,094
48255.66.240.0/20255.66.240.1 to 255.66.255.254255.66.255.2554,094
49255.67.0.0/20255.67.0.1 to 255.67.15.254255.67.15.2554,094
50255.67.16.0/20255.67.16.1 to 255.67.31.254255.67.31.2554,094
51255.67.32.0/20255.67.32.1 to 255.67.47.254255.67.47.2554,094
52255.67.48.0/20255.67.48.1 to 255.67.63.254255.67.63.2554,094
53255.67.64.0/20255.67.64.1 to 255.67.79.254255.67.79.2554,094
54255.67.80.0/20255.67.80.1 to 255.67.95.254255.67.95.2554,094
55255.67.96.0/20255.67.96.1 to 255.67.111.254255.67.111.2554,094
56255.67.112.0/20255.67.112.1 to 255.67.127.254255.67.127.2554,094
57255.67.128.0/20255.67.128.1 to 255.67.143.254255.67.143.2554,094
58255.67.144.0/20255.67.144.1 to 255.67.159.254255.67.159.2554,094
59255.67.160.0/20255.67.160.1 to 255.67.175.254255.67.175.2554,094
60255.67.176.0/20255.67.176.1 to 255.67.191.254255.67.191.2554,094
61255.67.192.0/20255.67.192.1 to 255.67.207.254255.67.207.2554,094
62255.67.208.0/20255.67.208.1 to 255.67.223.254255.67.223.2554,094
63255.67.224.0/20255.67.224.1 to 255.67.239.254255.67.239.2554,094
64255.67.240.0/20255.67.240.1 to 255.67.255.254255.67.255.2554,094
65255.68.0.0/20255.68.0.1 to 255.68.15.254255.68.15.2554,094
66255.68.16.0/20255.68.16.1 to 255.68.31.254255.68.31.2554,094
67255.68.32.0/20255.68.32.1 to 255.68.47.254255.68.47.2554,094
68255.68.48.0/20255.68.48.1 to 255.68.63.254255.68.63.2554,094
69255.68.64.0/20255.68.64.1 to 255.68.79.254255.68.79.2554,094
70255.68.80.0/20255.68.80.1 to 255.68.95.254255.68.95.2554,094
71255.68.96.0/20255.68.96.1 to 255.68.111.254255.68.111.2554,094
72255.68.112.0/20255.68.112.1 to 255.68.127.254255.68.127.2554,094
73255.68.128.0/20255.68.128.1 to 255.68.143.254255.68.143.2554,094
74255.68.144.0/20255.68.144.1 to 255.68.159.254255.68.159.2554,094
75255.68.160.0/20255.68.160.1 to 255.68.175.254255.68.175.2554,094
76255.68.176.0/20255.68.176.1 to 255.68.191.254255.68.191.2554,094
77255.68.192.0/20255.68.192.1 to 255.68.207.254255.68.207.2554,094
78255.68.208.0/20255.68.208.1 to 255.68.223.254255.68.223.2554,094
79255.68.224.0/20255.68.224.1 to 255.68.239.254255.68.239.2554,094
80255.68.240.0/20255.68.240.1 to 255.68.255.254255.68.255.2554,094
81255.69.0.0/20255.69.0.1 to 255.69.15.254255.69.15.2554,094
82255.69.16.0/20255.69.16.1 to 255.69.31.254255.69.31.2554,094
83255.69.32.0/20255.69.32.1 to 255.69.47.254255.69.47.2554,094
84255.69.48.0/20255.69.48.1 to 255.69.63.254255.69.63.2554,094
85255.69.64.0/20255.69.64.1 to 255.69.79.254255.69.79.2554,094
86255.69.80.0/20255.69.80.1 to 255.69.95.254255.69.95.2554,094
87255.69.96.0/20255.69.96.1 to 255.69.111.254255.69.111.2554,094
88255.69.112.0/20255.69.112.1 to 255.69.127.254255.69.127.2554,094
89255.69.128.0/20255.69.128.1 to 255.69.143.254255.69.143.2554,094
90255.69.144.0/20255.69.144.1 to 255.69.159.254255.69.159.2554,094
91255.69.160.0/20255.69.160.1 to 255.69.175.254255.69.175.2554,094
92255.69.176.0/20255.69.176.1 to 255.69.191.254255.69.191.2554,094
93255.69.192.0/20255.69.192.1 to 255.69.207.254255.69.207.2554,094
94255.69.208.0/20255.69.208.1 to 255.69.223.254255.69.223.2554,094
95255.69.224.0/20255.69.224.1 to 255.69.239.254255.69.239.2554,094
96255.69.240.0/20255.69.240.1 to 255.69.255.254255.69.255.2554,094
97255.70.0.0/20255.70.0.1 to 255.70.15.254255.70.15.2554,094
98255.70.16.0/20255.70.16.1 to 255.70.31.254255.70.31.2554,094
99255.70.32.0/20255.70.32.1 to 255.70.47.254255.70.47.2554,094
100255.70.48.0/20255.70.48.1 to 255.70.63.254255.70.63.2554,094
101255.70.64.0/20255.70.64.1 to 255.70.79.254255.70.79.2554,094
102255.70.80.0/20255.70.80.1 to 255.70.95.254255.70.95.2554,094
103255.70.96.0/20255.70.96.1 to 255.70.111.254255.70.111.2554,094
104255.70.112.0/20255.70.112.1 to 255.70.127.254255.70.127.2554,094
105255.70.128.0/20255.70.128.1 to 255.70.143.254255.70.143.2554,094
106255.70.144.0/20255.70.144.1 to 255.70.159.254255.70.159.2554,094
107255.70.160.0/20255.70.160.1 to 255.70.175.254255.70.175.2554,094
108255.70.176.0/20255.70.176.1 to 255.70.191.254255.70.191.2554,094
109255.70.192.0/20255.70.192.1 to 255.70.207.254255.70.207.2554,094
110255.70.208.0/20255.70.208.1 to 255.70.223.254255.70.223.2554,094
111255.70.224.0/20255.70.224.1 to 255.70.239.254255.70.239.2554,094
112255.70.240.0/20255.70.240.1 to 255.70.255.254255.70.255.2554,094
113255.71.0.0/20255.71.0.1 to 255.71.15.254255.71.15.2554,094
114255.71.16.0/20255.71.16.1 to 255.71.31.254255.71.31.2554,094
115255.71.32.0/20255.71.32.1 to 255.71.47.254255.71.47.2554,094
116255.71.48.0/20255.71.48.1 to 255.71.63.254255.71.63.2554,094
117255.71.64.0/20255.71.64.1 to 255.71.79.254255.71.79.2554,094
118255.71.80.0/20255.71.80.1 to 255.71.95.254255.71.95.2554,094
119255.71.96.0/20255.71.96.1 to 255.71.111.254255.71.111.2554,094
120255.71.112.0/20255.71.112.1 to 255.71.127.254255.71.127.2554,094
121255.71.128.0/20255.71.128.1 to 255.71.143.254255.71.143.2554,094
122255.71.144.0/20255.71.144.1 to 255.71.159.254255.71.159.2554,094
123255.71.160.0/20255.71.160.1 to 255.71.175.254255.71.175.2554,094
124255.71.176.0/20255.71.176.1 to 255.71.191.254255.71.191.2554,094
125255.71.192.0/20255.71.192.1 to 255.71.207.254255.71.207.2554,094
126255.71.208.0/20255.71.208.1 to 255.71.223.254255.71.223.2554,094
127255.71.224.0/20255.71.224.1 to 255.71.239.254255.71.239.2554,094
128255.71.240.0/20255.71.240.1 to 255.71.255.254255.71.255.2554,094
129255.72.0.0/20255.72.0.1 to 255.72.15.254255.72.15.2554,094
130255.72.16.0/20255.72.16.1 to 255.72.31.254255.72.31.2554,094
131255.72.32.0/20255.72.32.1 to 255.72.47.254255.72.47.2554,094
132255.72.48.0/20255.72.48.1 to 255.72.63.254255.72.63.2554,094
133255.72.64.0/20255.72.64.1 to 255.72.79.254255.72.79.2554,094
134255.72.80.0/20255.72.80.1 to 255.72.95.254255.72.95.2554,094
135255.72.96.0/20255.72.96.1 to 255.72.111.254255.72.111.2554,094
136255.72.112.0/20255.72.112.1 to 255.72.127.254255.72.127.2554,094
137255.72.128.0/20255.72.128.1 to 255.72.143.254255.72.143.2554,094
138255.72.144.0/20255.72.144.1 to 255.72.159.254255.72.159.2554,094
139255.72.160.0/20255.72.160.1 to 255.72.175.254255.72.175.2554,094
140255.72.176.0/20255.72.176.1 to 255.72.191.254255.72.191.2554,094
141255.72.192.0/20255.72.192.1 to 255.72.207.254255.72.207.2554,094
142255.72.208.0/20255.72.208.1 to 255.72.223.254255.72.223.2554,094
143255.72.224.0/20255.72.224.1 to 255.72.239.254255.72.239.2554,094
144255.72.240.0/20255.72.240.1 to 255.72.255.254255.72.255.2554,094
145255.73.0.0/20255.73.0.1 to 255.73.15.254255.73.15.2554,094
146255.73.16.0/20255.73.16.1 to 255.73.31.254255.73.31.2554,094
147255.73.32.0/20255.73.32.1 to 255.73.47.254255.73.47.2554,094
148255.73.48.0/20255.73.48.1 to 255.73.63.254255.73.63.2554,094
149255.73.64.0/20255.73.64.1 to 255.73.79.254255.73.79.2554,094
150255.73.80.0/20255.73.80.1 to 255.73.95.254255.73.95.2554,094
151255.73.96.0/20255.73.96.1 to 255.73.111.254255.73.111.2554,094
152255.73.112.0/20255.73.112.1 to 255.73.127.254255.73.127.2554,094
153255.73.128.0/20255.73.128.1 to 255.73.143.254255.73.143.2554,094
154255.73.144.0/20255.73.144.1 to 255.73.159.254255.73.159.2554,094
155255.73.160.0/20255.73.160.1 to 255.73.175.254255.73.175.2554,094
156255.73.176.0/20255.73.176.1 to 255.73.191.254255.73.191.2554,094
157255.73.192.0/20255.73.192.1 to 255.73.207.254255.73.207.2554,094
158255.73.208.0/20255.73.208.1 to 255.73.223.254255.73.223.2554,094
159255.73.224.0/20255.73.224.1 to 255.73.239.254255.73.239.2554,094
160255.73.240.0/20255.73.240.1 to 255.73.255.254255.73.255.2554,094
161255.74.0.0/20255.74.0.1 to 255.74.15.254255.74.15.2554,094
162255.74.16.0/20255.74.16.1 to 255.74.31.254255.74.31.2554,094
163255.74.32.0/20255.74.32.1 to 255.74.47.254255.74.47.2554,094
164255.74.48.0/20255.74.48.1 to 255.74.63.254255.74.63.2554,094
165255.74.64.0/20255.74.64.1 to 255.74.79.254255.74.79.2554,094
166255.74.80.0/20255.74.80.1 to 255.74.95.254255.74.95.2554,094
167255.74.96.0/20255.74.96.1 to 255.74.111.254255.74.111.2554,094
168255.74.112.0/20255.74.112.1 to 255.74.127.254255.74.127.2554,094
169255.74.128.0/20255.74.128.1 to 255.74.143.254255.74.143.2554,094
170255.74.144.0/20255.74.144.1 to 255.74.159.254255.74.159.2554,094
171255.74.160.0/20255.74.160.1 to 255.74.175.254255.74.175.2554,094
172255.74.176.0/20255.74.176.1 to 255.74.191.254255.74.191.2554,094
173255.74.192.0/20255.74.192.1 to 255.74.207.254255.74.207.2554,094
174255.74.208.0/20255.74.208.1 to 255.74.223.254255.74.223.2554,094
175255.74.224.0/20255.74.224.1 to 255.74.239.254255.74.239.2554,094
176255.74.240.0/20255.74.240.1 to 255.74.255.254255.74.255.2554,094
177255.75.0.0/20255.75.0.1 to 255.75.15.254255.75.15.2554,094
178255.75.16.0/20255.75.16.1 to 255.75.31.254255.75.31.2554,094
179255.75.32.0/20255.75.32.1 to 255.75.47.254255.75.47.2554,094
180255.75.48.0/20255.75.48.1 to 255.75.63.254255.75.63.2554,094
181255.75.64.0/20255.75.64.1 to 255.75.79.254255.75.79.2554,094
182255.75.80.0/20255.75.80.1 to 255.75.95.254255.75.95.2554,094
183255.75.96.0/20255.75.96.1 to 255.75.111.254255.75.111.2554,094
184255.75.112.0/20255.75.112.1 to 255.75.127.254255.75.127.2554,094
185255.75.128.0/20255.75.128.1 to 255.75.143.254255.75.143.2554,094
186255.75.144.0/20255.75.144.1 to 255.75.159.254255.75.159.2554,094
187255.75.160.0/20255.75.160.1 to 255.75.175.254255.75.175.2554,094
188255.75.176.0/20255.75.176.1 to 255.75.191.254255.75.191.2554,094
189255.75.192.0/20255.75.192.1 to 255.75.207.254255.75.207.2554,094
190255.75.208.0/20255.75.208.1 to 255.75.223.254255.75.223.2554,094
191255.75.224.0/20255.75.224.1 to 255.75.239.254255.75.239.2554,094
192255.75.240.0/20255.75.240.1 to 255.75.255.254255.75.255.2554,094
193255.76.0.0/20255.76.0.1 to 255.76.15.254255.76.15.2554,094
194255.76.16.0/20255.76.16.1 to 255.76.31.254255.76.31.2554,094
195255.76.32.0/20255.76.32.1 to 255.76.47.254255.76.47.2554,094
196255.76.48.0/20255.76.48.1 to 255.76.63.254255.76.63.2554,094
197255.76.64.0/20255.76.64.1 to 255.76.79.254255.76.79.2554,094
198255.76.80.0/20255.76.80.1 to 255.76.95.254255.76.95.2554,094
199255.76.96.0/20255.76.96.1 to 255.76.111.254255.76.111.2554,094
200255.76.112.0/20255.76.112.1 to 255.76.127.254255.76.127.2554,094
201255.76.128.0/20255.76.128.1 to 255.76.143.254255.76.143.2554,094
202255.76.144.0/20255.76.144.1 to 255.76.159.254255.76.159.2554,094
203255.76.160.0/20255.76.160.1 to 255.76.175.254255.76.175.2554,094
204255.76.176.0/20255.76.176.1 to 255.76.191.254255.76.191.2554,094
205255.76.192.0/20255.76.192.1 to 255.76.207.254255.76.207.2554,094
206255.76.208.0/20255.76.208.1 to 255.76.223.254255.76.223.2554,094
207255.76.224.0/20255.76.224.1 to 255.76.239.254255.76.239.2554,094
208255.76.240.0/20255.76.240.1 to 255.76.255.254255.76.255.2554,094
209255.77.0.0/20255.77.0.1 to 255.77.15.254255.77.15.2554,094
210255.77.16.0/20255.77.16.1 to 255.77.31.254255.77.31.2554,094
211255.77.32.0/20255.77.32.1 to 255.77.47.254255.77.47.2554,094
212255.77.48.0/20255.77.48.1 to 255.77.63.254255.77.63.2554,094
213255.77.64.0/20255.77.64.1 to 255.77.79.254255.77.79.2554,094
214255.77.80.0/20255.77.80.1 to 255.77.95.254255.77.95.2554,094
215255.77.96.0/20255.77.96.1 to 255.77.111.254255.77.111.2554,094
216255.77.112.0/20255.77.112.1 to 255.77.127.254255.77.127.2554,094
217255.77.128.0/20255.77.128.1 to 255.77.143.254255.77.143.2554,094
218255.77.144.0/20255.77.144.1 to 255.77.159.254255.77.159.2554,094
219255.77.160.0/20255.77.160.1 to 255.77.175.254255.77.175.2554,094
220255.77.176.0/20255.77.176.1 to 255.77.191.254255.77.191.2554,094
221255.77.192.0/20255.77.192.1 to 255.77.207.254255.77.207.2554,094
222255.77.208.0/20255.77.208.1 to 255.77.223.254255.77.223.2554,094
223255.77.224.0/20255.77.224.1 to 255.77.239.254255.77.239.2554,094
224255.77.240.0/20255.77.240.1 to 255.77.255.254255.77.255.2554,094
225255.78.0.0/20255.78.0.1 to 255.78.15.254255.78.15.2554,094
226255.78.16.0/20255.78.16.1 to 255.78.31.254255.78.31.2554,094
227255.78.32.0/20255.78.32.1 to 255.78.47.254255.78.47.2554,094
228255.78.48.0/20255.78.48.1 to 255.78.63.254255.78.63.2554,094
229255.78.64.0/20255.78.64.1 to 255.78.79.254255.78.79.2554,094
230255.78.80.0/20255.78.80.1 to 255.78.95.254255.78.95.2554,094
231255.78.96.0/20255.78.96.1 to 255.78.111.254255.78.111.2554,094
232255.78.112.0/20255.78.112.1 to 255.78.127.254255.78.127.2554,094
233255.78.128.0/20255.78.128.1 to 255.78.143.254255.78.143.2554,094
234255.78.144.0/20255.78.144.1 to 255.78.159.254255.78.159.2554,094
235255.78.160.0/20255.78.160.1 to 255.78.175.254255.78.175.2554,094
236255.78.176.0/20255.78.176.1 to 255.78.191.254255.78.191.2554,094
237255.78.192.0/20255.78.192.1 to 255.78.207.254255.78.207.2554,094
238255.78.208.0/20255.78.208.1 to 255.78.223.254255.78.223.2554,094
239255.78.224.0/20255.78.224.1 to 255.78.239.254255.78.239.2554,094
240255.78.240.0/20255.78.240.1 to 255.78.255.254255.78.255.2554,094
241255.79.0.0/20255.79.0.1 to 255.79.15.254255.79.15.2554,094
242255.79.16.0/20255.79.16.1 to 255.79.31.254255.79.31.2554,094
243255.79.32.0/20255.79.32.1 to 255.79.47.254255.79.47.2554,094
244255.79.48.0/20255.79.48.1 to 255.79.63.254255.79.63.2554,094
245255.79.64.0/20255.79.64.1 to 255.79.79.254255.79.79.2554,094
246255.79.80.0/20255.79.80.1 to 255.79.95.254255.79.95.2554,094
247255.79.96.0/20255.79.96.1 to 255.79.111.254255.79.111.2554,094
248255.79.112.0/20255.79.112.1 to 255.79.127.254255.79.127.2554,094
249255.79.128.0/20255.79.128.1 to 255.79.143.254255.79.143.2554,094
250255.79.144.0/20255.79.144.1 to 255.79.159.254255.79.159.2554,094
251255.79.160.0/20255.79.160.1 to 255.79.175.254255.79.175.2554,094
252255.79.176.0/20255.79.176.1 to 255.79.191.254255.79.191.2554,094
253255.79.192.0/20255.79.192.1 to 255.79.207.254255.79.207.2554,094
254255.79.208.0/20255.79.208.1 to 255.79.223.254255.79.223.2554,094
255255.79.224.0/20255.79.224.1 to 255.79.239.254255.79.239.2554,094
256255.79.240.0/20255.79.240.1 to 255.79.255.254255.79.255.2554,094

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.