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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.

Prefix/16
Addresses2^112
/64 networks2^48
Network
fc2a::/16
First address
fc2a::
Last address
fc2a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
5,192,296,858,534,827,628,530,496,329,220,096 (2^112)
/64 networks (LANs)
281,474,976,710,656 (2^48)
Full form
fc2a:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
a.2.c.f.ip6.arpa
Split into smaller subnets/28
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

fc2a::/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
1fc2a::/28fc2a:f:ffff:ffff:ffff:ffff:ffff:ffff
2fc2a:10::/28fc2a:1f:ffff:ffff:ffff:ffff:ffff:ffff
3fc2a:20::/28fc2a:2f:ffff:ffff:ffff:ffff:ffff:ffff
4fc2a:30::/28fc2a:3f:ffff:ffff:ffff:ffff:ffff:ffff
5fc2a:40::/28fc2a:4f:ffff:ffff:ffff:ffff:ffff:ffff
6fc2a:50::/28fc2a:5f:ffff:ffff:ffff:ffff:ffff:ffff
7fc2a:60::/28fc2a:6f:ffff:ffff:ffff:ffff:ffff:ffff
8fc2a:70::/28fc2a:7f:ffff:ffff:ffff:ffff:ffff:ffff
9fc2a:80::/28fc2a:8f:ffff:ffff:ffff:ffff:ffff:ffff
10fc2a:90::/28fc2a:9f:ffff:ffff:ffff:ffff:ffff:ffff
11fc2a:a0::/28fc2a:af:ffff:ffff:ffff:ffff:ffff:ffff
12fc2a:b0::/28fc2a:bf:ffff:ffff:ffff:ffff:ffff:ffff
13fc2a:c0::/28fc2a:cf:ffff:ffff:ffff:ffff:ffff:ffff
14fc2a:d0::/28fc2a:df:ffff:ffff:ffff:ffff:ffff:ffff
15fc2a:e0::/28fc2a:ef:ffff:ffff:ffff:ffff:ffff:ffff
16fc2a:f0::/28fc2a:ff:ffff:ffff:ffff:ffff:ffff:ffff
17fc2a:100::/28fc2a:10f:ffff:ffff:ffff:ffff:ffff:ffff
18fc2a:110::/28fc2a:11f:ffff:ffff:ffff:ffff:ffff:ffff
19fc2a:120::/28fc2a:12f:ffff:ffff:ffff:ffff:ffff:ffff
20fc2a:130::/28fc2a:13f:ffff:ffff:ffff:ffff:ffff:ffff
21fc2a:140::/28fc2a:14f:ffff:ffff:ffff:ffff:ffff:ffff
22fc2a:150::/28fc2a:15f:ffff:ffff:ffff:ffff:ffff:ffff
23fc2a:160::/28fc2a:16f:ffff:ffff:ffff:ffff:ffff:ffff
24fc2a:170::/28fc2a:17f:ffff:ffff:ffff:ffff:ffff:ffff
25fc2a:180::/28fc2a:18f:ffff:ffff:ffff:ffff:ffff:ffff
26fc2a:190::/28fc2a:19f:ffff:ffff:ffff:ffff:ffff:ffff
27fc2a:1a0::/28fc2a:1af:ffff:ffff:ffff:ffff:ffff:ffff
28fc2a:1b0::/28fc2a:1bf:ffff:ffff:ffff:ffff:ffff:ffff
29fc2a:1c0::/28fc2a:1cf:ffff:ffff:ffff:ffff:ffff:ffff
30fc2a:1d0::/28fc2a:1df:ffff:ffff:ffff:ffff:ffff:ffff
31fc2a:1e0::/28fc2a:1ef:ffff:ffff:ffff:ffff:ffff:ffff
32fc2a:1f0::/28fc2a:1ff:ffff:ffff:ffff:ffff:ffff:ffff
33fc2a:200::/28fc2a:20f:ffff:ffff:ffff:ffff:ffff:ffff
34fc2a:210::/28fc2a:21f:ffff:ffff:ffff:ffff:ffff:ffff
35fc2a:220::/28fc2a:22f:ffff:ffff:ffff:ffff:ffff:ffff
36fc2a:230::/28fc2a:23f:ffff:ffff:ffff:ffff:ffff:ffff
37fc2a:240::/28fc2a:24f:ffff:ffff:ffff:ffff:ffff:ffff
38fc2a:250::/28fc2a:25f:ffff:ffff:ffff:ffff:ffff:ffff
39fc2a:260::/28fc2a:26f:ffff:ffff:ffff:ffff:ffff:ffff
40fc2a:270::/28fc2a:27f:ffff:ffff:ffff:ffff:ffff:ffff
41fc2a:280::/28fc2a:28f:ffff:ffff:ffff:ffff:ffff:ffff
42fc2a:290::/28fc2a:29f:ffff:ffff:ffff:ffff:ffff:ffff
43fc2a:2a0::/28fc2a:2af:ffff:ffff:ffff:ffff:ffff:ffff
44fc2a:2b0::/28fc2a:2bf:ffff:ffff:ffff:ffff:ffff:ffff
45fc2a:2c0::/28fc2a:2cf:ffff:ffff:ffff:ffff:ffff:ffff
46fc2a:2d0::/28fc2a:2df:ffff:ffff:ffff:ffff:ffff:ffff
47fc2a:2e0::/28fc2a:2ef:ffff:ffff:ffff:ffff:ffff:ffff
48fc2a:2f0::/28fc2a:2ff:ffff:ffff:ffff:ffff:ffff:ffff
49fc2a:300::/28fc2a:30f:ffff:ffff:ffff:ffff:ffff:ffff
50fc2a:310::/28fc2a:31f:ffff:ffff:ffff:ffff:ffff:ffff
51fc2a:320::/28fc2a:32f:ffff:ffff:ffff:ffff:ffff:ffff
52fc2a:330::/28fc2a:33f:ffff:ffff:ffff:ffff:ffff:ffff
53fc2a:340::/28fc2a:34f:ffff:ffff:ffff:ffff:ffff:ffff
54fc2a:350::/28fc2a:35f:ffff:ffff:ffff:ffff:ffff:ffff
55fc2a:360::/28fc2a:36f:ffff:ffff:ffff:ffff:ffff:ffff
56fc2a:370::/28fc2a:37f:ffff:ffff:ffff:ffff:ffff:ffff
57fc2a:380::/28fc2a:38f:ffff:ffff:ffff:ffff:ffff:ffff
58fc2a:390::/28fc2a:39f:ffff:ffff:ffff:ffff:ffff:ffff
59fc2a:3a0::/28fc2a:3af:ffff:ffff:ffff:ffff:ffff:ffff
60fc2a:3b0::/28fc2a:3bf:ffff:ffff:ffff:ffff:ffff:ffff
61fc2a:3c0::/28fc2a:3cf:ffff:ffff:ffff:ffff:ffff:ffff
62fc2a:3d0::/28fc2a:3df:ffff:ffff:ffff:ffff:ffff:ffff
63fc2a:3e0::/28fc2a:3ef:ffff:ffff:ffff:ffff:ffff:ffff
64fc2a:3f0::/28fc2a:3ff:ffff:ffff:ffff:ffff:ffff:ffff
65fc2a:400::/28fc2a:40f:ffff:ffff:ffff:ffff:ffff:ffff
66fc2a:410::/28fc2a:41f:ffff:ffff:ffff:ffff:ffff:ffff
67fc2a:420::/28fc2a:42f:ffff:ffff:ffff:ffff:ffff:ffff
68fc2a:430::/28fc2a:43f:ffff:ffff:ffff:ffff:ffff:ffff
69fc2a:440::/28fc2a:44f:ffff:ffff:ffff:ffff:ffff:ffff
70fc2a:450::/28fc2a:45f:ffff:ffff:ffff:ffff:ffff:ffff
71fc2a:460::/28fc2a:46f:ffff:ffff:ffff:ffff:ffff:ffff
72fc2a:470::/28fc2a:47f:ffff:ffff:ffff:ffff:ffff:ffff
73fc2a:480::/28fc2a:48f:ffff:ffff:ffff:ffff:ffff:ffff
74fc2a:490::/28fc2a:49f:ffff:ffff:ffff:ffff:ffff:ffff
75fc2a:4a0::/28fc2a:4af:ffff:ffff:ffff:ffff:ffff:ffff
76fc2a:4b0::/28fc2a:4bf:ffff:ffff:ffff:ffff:ffff:ffff
77fc2a:4c0::/28fc2a:4cf:ffff:ffff:ffff:ffff:ffff:ffff
78fc2a:4d0::/28fc2a:4df:ffff:ffff:ffff:ffff:ffff:ffff
79fc2a:4e0::/28fc2a:4ef:ffff:ffff:ffff:ffff:ffff:ffff
80fc2a:4f0::/28fc2a:4ff:ffff:ffff:ffff:ffff:ffff:ffff
81fc2a:500::/28fc2a:50f:ffff:ffff:ffff:ffff:ffff:ffff
82fc2a:510::/28fc2a:51f:ffff:ffff:ffff:ffff:ffff:ffff
83fc2a:520::/28fc2a:52f:ffff:ffff:ffff:ffff:ffff:ffff
84fc2a:530::/28fc2a:53f:ffff:ffff:ffff:ffff:ffff:ffff
85fc2a:540::/28fc2a:54f:ffff:ffff:ffff:ffff:ffff:ffff
86fc2a:550::/28fc2a:55f:ffff:ffff:ffff:ffff:ffff:ffff
87fc2a:560::/28fc2a:56f:ffff:ffff:ffff:ffff:ffff:ffff
88fc2a:570::/28fc2a:57f:ffff:ffff:ffff:ffff:ffff:ffff
89fc2a:580::/28fc2a:58f:ffff:ffff:ffff:ffff:ffff:ffff
90fc2a:590::/28fc2a:59f:ffff:ffff:ffff:ffff:ffff:ffff
91fc2a:5a0::/28fc2a:5af:ffff:ffff:ffff:ffff:ffff:ffff
92fc2a:5b0::/28fc2a:5bf:ffff:ffff:ffff:ffff:ffff:ffff
93fc2a:5c0::/28fc2a:5cf:ffff:ffff:ffff:ffff:ffff:ffff
94fc2a:5d0::/28fc2a:5df:ffff:ffff:ffff:ffff:ffff:ffff
95fc2a:5e0::/28fc2a:5ef:ffff:ffff:ffff:ffff:ffff:ffff
96fc2a:5f0::/28fc2a:5ff:ffff:ffff:ffff:ffff:ffff:ffff
97fc2a:600::/28fc2a:60f:ffff:ffff:ffff:ffff:ffff:ffff
98fc2a:610::/28fc2a:61f:ffff:ffff:ffff:ffff:ffff:ffff
99fc2a:620::/28fc2a:62f:ffff:ffff:ffff:ffff:ffff:ffff
100fc2a:630::/28fc2a:63f:ffff:ffff:ffff:ffff:ffff:ffff
101fc2a:640::/28fc2a:64f:ffff:ffff:ffff:ffff:ffff:ffff
102fc2a:650::/28fc2a:65f:ffff:ffff:ffff:ffff:ffff:ffff
103fc2a:660::/28fc2a:66f:ffff:ffff:ffff:ffff:ffff:ffff
104fc2a:670::/28fc2a:67f:ffff:ffff:ffff:ffff:ffff:ffff
105fc2a:680::/28fc2a:68f:ffff:ffff:ffff:ffff:ffff:ffff
106fc2a:690::/28fc2a:69f:ffff:ffff:ffff:ffff:ffff:ffff
107fc2a:6a0::/28fc2a:6af:ffff:ffff:ffff:ffff:ffff:ffff
108fc2a:6b0::/28fc2a:6bf:ffff:ffff:ffff:ffff:ffff:ffff
109fc2a:6c0::/28fc2a:6cf:ffff:ffff:ffff:ffff:ffff:ffff
110fc2a:6d0::/28fc2a:6df:ffff:ffff:ffff:ffff:ffff:ffff
111fc2a:6e0::/28fc2a:6ef:ffff:ffff:ffff:ffff:ffff:ffff
112fc2a:6f0::/28fc2a:6ff:ffff:ffff:ffff:ffff:ffff:ffff
113fc2a:700::/28fc2a:70f:ffff:ffff:ffff:ffff:ffff:ffff
114fc2a:710::/28fc2a:71f:ffff:ffff:ffff:ffff:ffff:ffff
115fc2a:720::/28fc2a:72f:ffff:ffff:ffff:ffff:ffff:ffff
116fc2a:730::/28fc2a:73f:ffff:ffff:ffff:ffff:ffff:ffff
117fc2a:740::/28fc2a:74f:ffff:ffff:ffff:ffff:ffff:ffff
118fc2a:750::/28fc2a:75f:ffff:ffff:ffff:ffff:ffff:ffff
119fc2a:760::/28fc2a:76f:ffff:ffff:ffff:ffff:ffff:ffff
120fc2a:770::/28fc2a:77f:ffff:ffff:ffff:ffff:ffff:ffff
121fc2a:780::/28fc2a:78f:ffff:ffff:ffff:ffff:ffff:ffff
122fc2a:790::/28fc2a:79f:ffff:ffff:ffff:ffff:ffff:ffff
123fc2a:7a0::/28fc2a:7af:ffff:ffff:ffff:ffff:ffff:ffff
124fc2a:7b0::/28fc2a:7bf:ffff:ffff:ffff:ffff:ffff:ffff
125fc2a:7c0::/28fc2a:7cf:ffff:ffff:ffff:ffff:ffff:ffff
126fc2a:7d0::/28fc2a:7df:ffff:ffff:ffff:ffff:ffff:ffff
127fc2a:7e0::/28fc2a:7ef:ffff:ffff:ffff:ffff:ffff:ffff
128fc2a:7f0::/28fc2a:7ff:ffff:ffff:ffff:ffff:ffff:ffff
129fc2a:800::/28fc2a:80f:ffff:ffff:ffff:ffff:ffff:ffff
130fc2a:810::/28fc2a:81f:ffff:ffff:ffff:ffff:ffff:ffff
131fc2a:820::/28fc2a:82f:ffff:ffff:ffff:ffff:ffff:ffff
132fc2a:830::/28fc2a:83f:ffff:ffff:ffff:ffff:ffff:ffff
133fc2a:840::/28fc2a:84f:ffff:ffff:ffff:ffff:ffff:ffff
134fc2a:850::/28fc2a:85f:ffff:ffff:ffff:ffff:ffff:ffff
135fc2a:860::/28fc2a:86f:ffff:ffff:ffff:ffff:ffff:ffff
136fc2a:870::/28fc2a:87f:ffff:ffff:ffff:ffff:ffff:ffff
137fc2a:880::/28fc2a:88f:ffff:ffff:ffff:ffff:ffff:ffff
138fc2a:890::/28fc2a:89f:ffff:ffff:ffff:ffff:ffff:ffff
139fc2a:8a0::/28fc2a:8af:ffff:ffff:ffff:ffff:ffff:ffff
140fc2a:8b0::/28fc2a:8bf:ffff:ffff:ffff:ffff:ffff:ffff
141fc2a:8c0::/28fc2a:8cf:ffff:ffff:ffff:ffff:ffff:ffff
142fc2a:8d0::/28fc2a:8df:ffff:ffff:ffff:ffff:ffff:ffff
143fc2a:8e0::/28fc2a:8ef:ffff:ffff:ffff:ffff:ffff:ffff
144fc2a:8f0::/28fc2a:8ff:ffff:ffff:ffff:ffff:ffff:ffff
145fc2a:900::/28fc2a:90f:ffff:ffff:ffff:ffff:ffff:ffff
146fc2a:910::/28fc2a:91f:ffff:ffff:ffff:ffff:ffff:ffff
147fc2a:920::/28fc2a:92f:ffff:ffff:ffff:ffff:ffff:ffff
148fc2a:930::/28fc2a:93f:ffff:ffff:ffff:ffff:ffff:ffff
149fc2a:940::/28fc2a:94f:ffff:ffff:ffff:ffff:ffff:ffff
150fc2a:950::/28fc2a:95f:ffff:ffff:ffff:ffff:ffff:ffff
151fc2a:960::/28fc2a:96f:ffff:ffff:ffff:ffff:ffff:ffff
152fc2a:970::/28fc2a:97f:ffff:ffff:ffff:ffff:ffff:ffff
153fc2a:980::/28fc2a:98f:ffff:ffff:ffff:ffff:ffff:ffff
154fc2a:990::/28fc2a:99f:ffff:ffff:ffff:ffff:ffff:ffff
155fc2a:9a0::/28fc2a:9af:ffff:ffff:ffff:ffff:ffff:ffff
156fc2a:9b0::/28fc2a:9bf:ffff:ffff:ffff:ffff:ffff:ffff
157fc2a:9c0::/28fc2a:9cf:ffff:ffff:ffff:ffff:ffff:ffff
158fc2a:9d0::/28fc2a:9df:ffff:ffff:ffff:ffff:ffff:ffff
159fc2a:9e0::/28fc2a:9ef:ffff:ffff:ffff:ffff:ffff:ffff
160fc2a:9f0::/28fc2a:9ff:ffff:ffff:ffff:ffff:ffff:ffff
161fc2a:a00::/28fc2a:a0f:ffff:ffff:ffff:ffff:ffff:ffff
162fc2a:a10::/28fc2a:a1f:ffff:ffff:ffff:ffff:ffff:ffff
163fc2a:a20::/28fc2a:a2f:ffff:ffff:ffff:ffff:ffff:ffff
164fc2a:a30::/28fc2a:a3f:ffff:ffff:ffff:ffff:ffff:ffff
165fc2a:a40::/28fc2a:a4f:ffff:ffff:ffff:ffff:ffff:ffff
166fc2a:a50::/28fc2a:a5f:ffff:ffff:ffff:ffff:ffff:ffff
167fc2a:a60::/28fc2a:a6f:ffff:ffff:ffff:ffff:ffff:ffff
168fc2a:a70::/28fc2a:a7f:ffff:ffff:ffff:ffff:ffff:ffff
169fc2a:a80::/28fc2a:a8f:ffff:ffff:ffff:ffff:ffff:ffff
170fc2a:a90::/28fc2a:a9f:ffff:ffff:ffff:ffff:ffff:ffff
171fc2a:aa0::/28fc2a:aaf:ffff:ffff:ffff:ffff:ffff:ffff
172fc2a:ab0::/28fc2a:abf:ffff:ffff:ffff:ffff:ffff:ffff
173fc2a:ac0::/28fc2a:acf:ffff:ffff:ffff:ffff:ffff:ffff
174fc2a:ad0::/28fc2a:adf:ffff:ffff:ffff:ffff:ffff:ffff
175fc2a:ae0::/28fc2a:aef:ffff:ffff:ffff:ffff:ffff:ffff
176fc2a:af0::/28fc2a:aff:ffff:ffff:ffff:ffff:ffff:ffff
177fc2a:b00::/28fc2a:b0f:ffff:ffff:ffff:ffff:ffff:ffff
178fc2a:b10::/28fc2a:b1f:ffff:ffff:ffff:ffff:ffff:ffff
179fc2a:b20::/28fc2a:b2f:ffff:ffff:ffff:ffff:ffff:ffff
180fc2a:b30::/28fc2a:b3f:ffff:ffff:ffff:ffff:ffff:ffff
181fc2a:b40::/28fc2a:b4f:ffff:ffff:ffff:ffff:ffff:ffff
182fc2a:b50::/28fc2a:b5f:ffff:ffff:ffff:ffff:ffff:ffff
183fc2a:b60::/28fc2a:b6f:ffff:ffff:ffff:ffff:ffff:ffff
184fc2a:b70::/28fc2a:b7f:ffff:ffff:ffff:ffff:ffff:ffff
185fc2a:b80::/28fc2a:b8f:ffff:ffff:ffff:ffff:ffff:ffff
186fc2a:b90::/28fc2a:b9f:ffff:ffff:ffff:ffff:ffff:ffff
187fc2a:ba0::/28fc2a:baf:ffff:ffff:ffff:ffff:ffff:ffff
188fc2a:bb0::/28fc2a:bbf:ffff:ffff:ffff:ffff:ffff:ffff
189fc2a:bc0::/28fc2a:bcf:ffff:ffff:ffff:ffff:ffff:ffff
190fc2a:bd0::/28fc2a:bdf:ffff:ffff:ffff:ffff:ffff:ffff
191fc2a:be0::/28fc2a:bef:ffff:ffff:ffff:ffff:ffff:ffff
192fc2a:bf0::/28fc2a:bff:ffff:ffff:ffff:ffff:ffff:ffff
193fc2a:c00::/28fc2a:c0f:ffff:ffff:ffff:ffff:ffff:ffff
194fc2a:c10::/28fc2a:c1f:ffff:ffff:ffff:ffff:ffff:ffff
195fc2a:c20::/28fc2a:c2f:ffff:ffff:ffff:ffff:ffff:ffff
196fc2a:c30::/28fc2a:c3f:ffff:ffff:ffff:ffff:ffff:ffff
197fc2a:c40::/28fc2a:c4f:ffff:ffff:ffff:ffff:ffff:ffff
198fc2a:c50::/28fc2a:c5f:ffff:ffff:ffff:ffff:ffff:ffff
199fc2a:c60::/28fc2a:c6f:ffff:ffff:ffff:ffff:ffff:ffff
200fc2a:c70::/28fc2a:c7f:ffff:ffff:ffff:ffff:ffff:ffff
201fc2a:c80::/28fc2a:c8f:ffff:ffff:ffff:ffff:ffff:ffff
202fc2a:c90::/28fc2a:c9f:ffff:ffff:ffff:ffff:ffff:ffff
203fc2a:ca0::/28fc2a:caf:ffff:ffff:ffff:ffff:ffff:ffff
204fc2a:cb0::/28fc2a:cbf:ffff:ffff:ffff:ffff:ffff:ffff
205fc2a:cc0::/28fc2a:ccf:ffff:ffff:ffff:ffff:ffff:ffff
206fc2a:cd0::/28fc2a:cdf:ffff:ffff:ffff:ffff:ffff:ffff
207fc2a:ce0::/28fc2a:cef:ffff:ffff:ffff:ffff:ffff:ffff
208fc2a:cf0::/28fc2a:cff:ffff:ffff:ffff:ffff:ffff:ffff
209fc2a:d00::/28fc2a:d0f:ffff:ffff:ffff:ffff:ffff:ffff
210fc2a:d10::/28fc2a:d1f:ffff:ffff:ffff:ffff:ffff:ffff
211fc2a:d20::/28fc2a:d2f:ffff:ffff:ffff:ffff:ffff:ffff
212fc2a:d30::/28fc2a:d3f:ffff:ffff:ffff:ffff:ffff:ffff
213fc2a:d40::/28fc2a:d4f:ffff:ffff:ffff:ffff:ffff:ffff
214fc2a:d50::/28fc2a:d5f:ffff:ffff:ffff:ffff:ffff:ffff
215fc2a:d60::/28fc2a:d6f:ffff:ffff:ffff:ffff:ffff:ffff
216fc2a:d70::/28fc2a:d7f:ffff:ffff:ffff:ffff:ffff:ffff
217fc2a:d80::/28fc2a:d8f:ffff:ffff:ffff:ffff:ffff:ffff
218fc2a:d90::/28fc2a:d9f:ffff:ffff:ffff:ffff:ffff:ffff
219fc2a:da0::/28fc2a:daf:ffff:ffff:ffff:ffff:ffff:ffff
220fc2a:db0::/28fc2a:dbf:ffff:ffff:ffff:ffff:ffff:ffff
221fc2a:dc0::/28fc2a:dcf:ffff:ffff:ffff:ffff:ffff:ffff
222fc2a:dd0::/28fc2a:ddf:ffff:ffff:ffff:ffff:ffff:ffff
223fc2a:de0::/28fc2a:def:ffff:ffff:ffff:ffff:ffff:ffff
224fc2a:df0::/28fc2a:dff:ffff:ffff:ffff:ffff:ffff:ffff
225fc2a:e00::/28fc2a:e0f:ffff:ffff:ffff:ffff:ffff:ffff
226fc2a:e10::/28fc2a:e1f:ffff:ffff:ffff:ffff:ffff:ffff
227fc2a:e20::/28fc2a:e2f:ffff:ffff:ffff:ffff:ffff:ffff
228fc2a:e30::/28fc2a:e3f:ffff:ffff:ffff:ffff:ffff:ffff
229fc2a:e40::/28fc2a:e4f:ffff:ffff:ffff:ffff:ffff:ffff
230fc2a:e50::/28fc2a:e5f:ffff:ffff:ffff:ffff:ffff:ffff
231fc2a:e60::/28fc2a:e6f:ffff:ffff:ffff:ffff:ffff:ffff
232fc2a:e70::/28fc2a:e7f:ffff:ffff:ffff:ffff:ffff:ffff
233fc2a:e80::/28fc2a:e8f:ffff:ffff:ffff:ffff:ffff:ffff
234fc2a:e90::/28fc2a:e9f:ffff:ffff:ffff:ffff:ffff:ffff
235fc2a:ea0::/28fc2a:eaf:ffff:ffff:ffff:ffff:ffff:ffff
236fc2a:eb0::/28fc2a:ebf:ffff:ffff:ffff:ffff:ffff:ffff
237fc2a:ec0::/28fc2a:ecf:ffff:ffff:ffff:ffff:ffff:ffff
238fc2a:ed0::/28fc2a:edf:ffff:ffff:ffff:ffff:ffff:ffff
239fc2a:ee0::/28fc2a:eef:ffff:ffff:ffff:ffff:ffff:ffff
240fc2a:ef0::/28fc2a:eff:ffff:ffff:ffff:ffff:ffff:ffff
241fc2a:f00::/28fc2a:f0f:ffff:ffff:ffff:ffff:ffff:ffff
242fc2a:f10::/28fc2a:f1f:ffff:ffff:ffff:ffff:ffff:ffff
243fc2a:f20::/28fc2a:f2f:ffff:ffff:ffff:ffff:ffff:ffff
244fc2a:f30::/28fc2a:f3f:ffff:ffff:ffff:ffff:ffff:ffff
245fc2a:f40::/28fc2a:f4f:ffff:ffff:ffff:ffff:ffff:ffff
246fc2a:f50::/28fc2a:f5f:ffff:ffff:ffff:ffff:ffff:ffff
247fc2a:f60::/28fc2a:f6f:ffff:ffff:ffff:ffff:ffff:ffff
248fc2a:f70::/28fc2a:f7f:ffff:ffff:ffff:ffff:ffff:ffff
249fc2a:f80::/28fc2a:f8f:ffff:ffff:ffff:ffff:ffff:ffff
250fc2a:f90::/28fc2a:f9f:ffff:ffff:ffff:ffff:ffff:ffff
251fc2a:fa0::/28fc2a:faf:ffff:ffff:ffff:ffff:ffff:ffff
252fc2a:fb0::/28fc2a:fbf:ffff:ffff:ffff:ffff:ffff:ffff
253fc2a:fc0::/28fc2a:fcf:ffff:ffff:ffff:ffff:ffff:ffff
254fc2a:fd0::/28fc2a:fdf:ffff:ffff:ffff:ffff:ffff:ffff
255fc2a:fe0::/28fc2a:fef:ffff:ffff:ffff:ffff:ffff:ffff
256fc2a:ff0::/28fc2a:fff:ffff:ffff:ffff:ffff:ffff:ffff

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.