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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
fc4d::/16
First address
fc4d::
Last address
fc4d: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
fc4d:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
d.4.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)

fc4d::/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
1fc4d::/28fc4d:f:ffff:ffff:ffff:ffff:ffff:ffff
2fc4d:10::/28fc4d:1f:ffff:ffff:ffff:ffff:ffff:ffff
3fc4d:20::/28fc4d:2f:ffff:ffff:ffff:ffff:ffff:ffff
4fc4d:30::/28fc4d:3f:ffff:ffff:ffff:ffff:ffff:ffff
5fc4d:40::/28fc4d:4f:ffff:ffff:ffff:ffff:ffff:ffff
6fc4d:50::/28fc4d:5f:ffff:ffff:ffff:ffff:ffff:ffff
7fc4d:60::/28fc4d:6f:ffff:ffff:ffff:ffff:ffff:ffff
8fc4d:70::/28fc4d:7f:ffff:ffff:ffff:ffff:ffff:ffff
9fc4d:80::/28fc4d:8f:ffff:ffff:ffff:ffff:ffff:ffff
10fc4d:90::/28fc4d:9f:ffff:ffff:ffff:ffff:ffff:ffff
11fc4d:a0::/28fc4d:af:ffff:ffff:ffff:ffff:ffff:ffff
12fc4d:b0::/28fc4d:bf:ffff:ffff:ffff:ffff:ffff:ffff
13fc4d:c0::/28fc4d:cf:ffff:ffff:ffff:ffff:ffff:ffff
14fc4d:d0::/28fc4d:df:ffff:ffff:ffff:ffff:ffff:ffff
15fc4d:e0::/28fc4d:ef:ffff:ffff:ffff:ffff:ffff:ffff
16fc4d:f0::/28fc4d:ff:ffff:ffff:ffff:ffff:ffff:ffff
17fc4d:100::/28fc4d:10f:ffff:ffff:ffff:ffff:ffff:ffff
18fc4d:110::/28fc4d:11f:ffff:ffff:ffff:ffff:ffff:ffff
19fc4d:120::/28fc4d:12f:ffff:ffff:ffff:ffff:ffff:ffff
20fc4d:130::/28fc4d:13f:ffff:ffff:ffff:ffff:ffff:ffff
21fc4d:140::/28fc4d:14f:ffff:ffff:ffff:ffff:ffff:ffff
22fc4d:150::/28fc4d:15f:ffff:ffff:ffff:ffff:ffff:ffff
23fc4d:160::/28fc4d:16f:ffff:ffff:ffff:ffff:ffff:ffff
24fc4d:170::/28fc4d:17f:ffff:ffff:ffff:ffff:ffff:ffff
25fc4d:180::/28fc4d:18f:ffff:ffff:ffff:ffff:ffff:ffff
26fc4d:190::/28fc4d:19f:ffff:ffff:ffff:ffff:ffff:ffff
27fc4d:1a0::/28fc4d:1af:ffff:ffff:ffff:ffff:ffff:ffff
28fc4d:1b0::/28fc4d:1bf:ffff:ffff:ffff:ffff:ffff:ffff
29fc4d:1c0::/28fc4d:1cf:ffff:ffff:ffff:ffff:ffff:ffff
30fc4d:1d0::/28fc4d:1df:ffff:ffff:ffff:ffff:ffff:ffff
31fc4d:1e0::/28fc4d:1ef:ffff:ffff:ffff:ffff:ffff:ffff
32fc4d:1f0::/28fc4d:1ff:ffff:ffff:ffff:ffff:ffff:ffff
33fc4d:200::/28fc4d:20f:ffff:ffff:ffff:ffff:ffff:ffff
34fc4d:210::/28fc4d:21f:ffff:ffff:ffff:ffff:ffff:ffff
35fc4d:220::/28fc4d:22f:ffff:ffff:ffff:ffff:ffff:ffff
36fc4d:230::/28fc4d:23f:ffff:ffff:ffff:ffff:ffff:ffff
37fc4d:240::/28fc4d:24f:ffff:ffff:ffff:ffff:ffff:ffff
38fc4d:250::/28fc4d:25f:ffff:ffff:ffff:ffff:ffff:ffff
39fc4d:260::/28fc4d:26f:ffff:ffff:ffff:ffff:ffff:ffff
40fc4d:270::/28fc4d:27f:ffff:ffff:ffff:ffff:ffff:ffff
41fc4d:280::/28fc4d:28f:ffff:ffff:ffff:ffff:ffff:ffff
42fc4d:290::/28fc4d:29f:ffff:ffff:ffff:ffff:ffff:ffff
43fc4d:2a0::/28fc4d:2af:ffff:ffff:ffff:ffff:ffff:ffff
44fc4d:2b0::/28fc4d:2bf:ffff:ffff:ffff:ffff:ffff:ffff
45fc4d:2c0::/28fc4d:2cf:ffff:ffff:ffff:ffff:ffff:ffff
46fc4d:2d0::/28fc4d:2df:ffff:ffff:ffff:ffff:ffff:ffff
47fc4d:2e0::/28fc4d:2ef:ffff:ffff:ffff:ffff:ffff:ffff
48fc4d:2f0::/28fc4d:2ff:ffff:ffff:ffff:ffff:ffff:ffff
49fc4d:300::/28fc4d:30f:ffff:ffff:ffff:ffff:ffff:ffff
50fc4d:310::/28fc4d:31f:ffff:ffff:ffff:ffff:ffff:ffff
51fc4d:320::/28fc4d:32f:ffff:ffff:ffff:ffff:ffff:ffff
52fc4d:330::/28fc4d:33f:ffff:ffff:ffff:ffff:ffff:ffff
53fc4d:340::/28fc4d:34f:ffff:ffff:ffff:ffff:ffff:ffff
54fc4d:350::/28fc4d:35f:ffff:ffff:ffff:ffff:ffff:ffff
55fc4d:360::/28fc4d:36f:ffff:ffff:ffff:ffff:ffff:ffff
56fc4d:370::/28fc4d:37f:ffff:ffff:ffff:ffff:ffff:ffff
57fc4d:380::/28fc4d:38f:ffff:ffff:ffff:ffff:ffff:ffff
58fc4d:390::/28fc4d:39f:ffff:ffff:ffff:ffff:ffff:ffff
59fc4d:3a0::/28fc4d:3af:ffff:ffff:ffff:ffff:ffff:ffff
60fc4d:3b0::/28fc4d:3bf:ffff:ffff:ffff:ffff:ffff:ffff
61fc4d:3c0::/28fc4d:3cf:ffff:ffff:ffff:ffff:ffff:ffff
62fc4d:3d0::/28fc4d:3df:ffff:ffff:ffff:ffff:ffff:ffff
63fc4d:3e0::/28fc4d:3ef:ffff:ffff:ffff:ffff:ffff:ffff
64fc4d:3f0::/28fc4d:3ff:ffff:ffff:ffff:ffff:ffff:ffff
65fc4d:400::/28fc4d:40f:ffff:ffff:ffff:ffff:ffff:ffff
66fc4d:410::/28fc4d:41f:ffff:ffff:ffff:ffff:ffff:ffff
67fc4d:420::/28fc4d:42f:ffff:ffff:ffff:ffff:ffff:ffff
68fc4d:430::/28fc4d:43f:ffff:ffff:ffff:ffff:ffff:ffff
69fc4d:440::/28fc4d:44f:ffff:ffff:ffff:ffff:ffff:ffff
70fc4d:450::/28fc4d:45f:ffff:ffff:ffff:ffff:ffff:ffff
71fc4d:460::/28fc4d:46f:ffff:ffff:ffff:ffff:ffff:ffff
72fc4d:470::/28fc4d:47f:ffff:ffff:ffff:ffff:ffff:ffff
73fc4d:480::/28fc4d:48f:ffff:ffff:ffff:ffff:ffff:ffff
74fc4d:490::/28fc4d:49f:ffff:ffff:ffff:ffff:ffff:ffff
75fc4d:4a0::/28fc4d:4af:ffff:ffff:ffff:ffff:ffff:ffff
76fc4d:4b0::/28fc4d:4bf:ffff:ffff:ffff:ffff:ffff:ffff
77fc4d:4c0::/28fc4d:4cf:ffff:ffff:ffff:ffff:ffff:ffff
78fc4d:4d0::/28fc4d:4df:ffff:ffff:ffff:ffff:ffff:ffff
79fc4d:4e0::/28fc4d:4ef:ffff:ffff:ffff:ffff:ffff:ffff
80fc4d:4f0::/28fc4d:4ff:ffff:ffff:ffff:ffff:ffff:ffff
81fc4d:500::/28fc4d:50f:ffff:ffff:ffff:ffff:ffff:ffff
82fc4d:510::/28fc4d:51f:ffff:ffff:ffff:ffff:ffff:ffff
83fc4d:520::/28fc4d:52f:ffff:ffff:ffff:ffff:ffff:ffff
84fc4d:530::/28fc4d:53f:ffff:ffff:ffff:ffff:ffff:ffff
85fc4d:540::/28fc4d:54f:ffff:ffff:ffff:ffff:ffff:ffff
86fc4d:550::/28fc4d:55f:ffff:ffff:ffff:ffff:ffff:ffff
87fc4d:560::/28fc4d:56f:ffff:ffff:ffff:ffff:ffff:ffff
88fc4d:570::/28fc4d:57f:ffff:ffff:ffff:ffff:ffff:ffff
89fc4d:580::/28fc4d:58f:ffff:ffff:ffff:ffff:ffff:ffff
90fc4d:590::/28fc4d:59f:ffff:ffff:ffff:ffff:ffff:ffff
91fc4d:5a0::/28fc4d:5af:ffff:ffff:ffff:ffff:ffff:ffff
92fc4d:5b0::/28fc4d:5bf:ffff:ffff:ffff:ffff:ffff:ffff
93fc4d:5c0::/28fc4d:5cf:ffff:ffff:ffff:ffff:ffff:ffff
94fc4d:5d0::/28fc4d:5df:ffff:ffff:ffff:ffff:ffff:ffff
95fc4d:5e0::/28fc4d:5ef:ffff:ffff:ffff:ffff:ffff:ffff
96fc4d:5f0::/28fc4d:5ff:ffff:ffff:ffff:ffff:ffff:ffff
97fc4d:600::/28fc4d:60f:ffff:ffff:ffff:ffff:ffff:ffff
98fc4d:610::/28fc4d:61f:ffff:ffff:ffff:ffff:ffff:ffff
99fc4d:620::/28fc4d:62f:ffff:ffff:ffff:ffff:ffff:ffff
100fc4d:630::/28fc4d:63f:ffff:ffff:ffff:ffff:ffff:ffff
101fc4d:640::/28fc4d:64f:ffff:ffff:ffff:ffff:ffff:ffff
102fc4d:650::/28fc4d:65f:ffff:ffff:ffff:ffff:ffff:ffff
103fc4d:660::/28fc4d:66f:ffff:ffff:ffff:ffff:ffff:ffff
104fc4d:670::/28fc4d:67f:ffff:ffff:ffff:ffff:ffff:ffff
105fc4d:680::/28fc4d:68f:ffff:ffff:ffff:ffff:ffff:ffff
106fc4d:690::/28fc4d:69f:ffff:ffff:ffff:ffff:ffff:ffff
107fc4d:6a0::/28fc4d:6af:ffff:ffff:ffff:ffff:ffff:ffff
108fc4d:6b0::/28fc4d:6bf:ffff:ffff:ffff:ffff:ffff:ffff
109fc4d:6c0::/28fc4d:6cf:ffff:ffff:ffff:ffff:ffff:ffff
110fc4d:6d0::/28fc4d:6df:ffff:ffff:ffff:ffff:ffff:ffff
111fc4d:6e0::/28fc4d:6ef:ffff:ffff:ffff:ffff:ffff:ffff
112fc4d:6f0::/28fc4d:6ff:ffff:ffff:ffff:ffff:ffff:ffff
113fc4d:700::/28fc4d:70f:ffff:ffff:ffff:ffff:ffff:ffff
114fc4d:710::/28fc4d:71f:ffff:ffff:ffff:ffff:ffff:ffff
115fc4d:720::/28fc4d:72f:ffff:ffff:ffff:ffff:ffff:ffff
116fc4d:730::/28fc4d:73f:ffff:ffff:ffff:ffff:ffff:ffff
117fc4d:740::/28fc4d:74f:ffff:ffff:ffff:ffff:ffff:ffff
118fc4d:750::/28fc4d:75f:ffff:ffff:ffff:ffff:ffff:ffff
119fc4d:760::/28fc4d:76f:ffff:ffff:ffff:ffff:ffff:ffff
120fc4d:770::/28fc4d:77f:ffff:ffff:ffff:ffff:ffff:ffff
121fc4d:780::/28fc4d:78f:ffff:ffff:ffff:ffff:ffff:ffff
122fc4d:790::/28fc4d:79f:ffff:ffff:ffff:ffff:ffff:ffff
123fc4d:7a0::/28fc4d:7af:ffff:ffff:ffff:ffff:ffff:ffff
124fc4d:7b0::/28fc4d:7bf:ffff:ffff:ffff:ffff:ffff:ffff
125fc4d:7c0::/28fc4d:7cf:ffff:ffff:ffff:ffff:ffff:ffff
126fc4d:7d0::/28fc4d:7df:ffff:ffff:ffff:ffff:ffff:ffff
127fc4d:7e0::/28fc4d:7ef:ffff:ffff:ffff:ffff:ffff:ffff
128fc4d:7f0::/28fc4d:7ff:ffff:ffff:ffff:ffff:ffff:ffff
129fc4d:800::/28fc4d:80f:ffff:ffff:ffff:ffff:ffff:ffff
130fc4d:810::/28fc4d:81f:ffff:ffff:ffff:ffff:ffff:ffff
131fc4d:820::/28fc4d:82f:ffff:ffff:ffff:ffff:ffff:ffff
132fc4d:830::/28fc4d:83f:ffff:ffff:ffff:ffff:ffff:ffff
133fc4d:840::/28fc4d:84f:ffff:ffff:ffff:ffff:ffff:ffff
134fc4d:850::/28fc4d:85f:ffff:ffff:ffff:ffff:ffff:ffff
135fc4d:860::/28fc4d:86f:ffff:ffff:ffff:ffff:ffff:ffff
136fc4d:870::/28fc4d:87f:ffff:ffff:ffff:ffff:ffff:ffff
137fc4d:880::/28fc4d:88f:ffff:ffff:ffff:ffff:ffff:ffff
138fc4d:890::/28fc4d:89f:ffff:ffff:ffff:ffff:ffff:ffff
139fc4d:8a0::/28fc4d:8af:ffff:ffff:ffff:ffff:ffff:ffff
140fc4d:8b0::/28fc4d:8bf:ffff:ffff:ffff:ffff:ffff:ffff
141fc4d:8c0::/28fc4d:8cf:ffff:ffff:ffff:ffff:ffff:ffff
142fc4d:8d0::/28fc4d:8df:ffff:ffff:ffff:ffff:ffff:ffff
143fc4d:8e0::/28fc4d:8ef:ffff:ffff:ffff:ffff:ffff:ffff
144fc4d:8f0::/28fc4d:8ff:ffff:ffff:ffff:ffff:ffff:ffff
145fc4d:900::/28fc4d:90f:ffff:ffff:ffff:ffff:ffff:ffff
146fc4d:910::/28fc4d:91f:ffff:ffff:ffff:ffff:ffff:ffff
147fc4d:920::/28fc4d:92f:ffff:ffff:ffff:ffff:ffff:ffff
148fc4d:930::/28fc4d:93f:ffff:ffff:ffff:ffff:ffff:ffff
149fc4d:940::/28fc4d:94f:ffff:ffff:ffff:ffff:ffff:ffff
150fc4d:950::/28fc4d:95f:ffff:ffff:ffff:ffff:ffff:ffff
151fc4d:960::/28fc4d:96f:ffff:ffff:ffff:ffff:ffff:ffff
152fc4d:970::/28fc4d:97f:ffff:ffff:ffff:ffff:ffff:ffff
153fc4d:980::/28fc4d:98f:ffff:ffff:ffff:ffff:ffff:ffff
154fc4d:990::/28fc4d:99f:ffff:ffff:ffff:ffff:ffff:ffff
155fc4d:9a0::/28fc4d:9af:ffff:ffff:ffff:ffff:ffff:ffff
156fc4d:9b0::/28fc4d:9bf:ffff:ffff:ffff:ffff:ffff:ffff
157fc4d:9c0::/28fc4d:9cf:ffff:ffff:ffff:ffff:ffff:ffff
158fc4d:9d0::/28fc4d:9df:ffff:ffff:ffff:ffff:ffff:ffff
159fc4d:9e0::/28fc4d:9ef:ffff:ffff:ffff:ffff:ffff:ffff
160fc4d:9f0::/28fc4d:9ff:ffff:ffff:ffff:ffff:ffff:ffff
161fc4d:a00::/28fc4d:a0f:ffff:ffff:ffff:ffff:ffff:ffff
162fc4d:a10::/28fc4d:a1f:ffff:ffff:ffff:ffff:ffff:ffff
163fc4d:a20::/28fc4d:a2f:ffff:ffff:ffff:ffff:ffff:ffff
164fc4d:a30::/28fc4d:a3f:ffff:ffff:ffff:ffff:ffff:ffff
165fc4d:a40::/28fc4d:a4f:ffff:ffff:ffff:ffff:ffff:ffff
166fc4d:a50::/28fc4d:a5f:ffff:ffff:ffff:ffff:ffff:ffff
167fc4d:a60::/28fc4d:a6f:ffff:ffff:ffff:ffff:ffff:ffff
168fc4d:a70::/28fc4d:a7f:ffff:ffff:ffff:ffff:ffff:ffff
169fc4d:a80::/28fc4d:a8f:ffff:ffff:ffff:ffff:ffff:ffff
170fc4d:a90::/28fc4d:a9f:ffff:ffff:ffff:ffff:ffff:ffff
171fc4d:aa0::/28fc4d:aaf:ffff:ffff:ffff:ffff:ffff:ffff
172fc4d:ab0::/28fc4d:abf:ffff:ffff:ffff:ffff:ffff:ffff
173fc4d:ac0::/28fc4d:acf:ffff:ffff:ffff:ffff:ffff:ffff
174fc4d:ad0::/28fc4d:adf:ffff:ffff:ffff:ffff:ffff:ffff
175fc4d:ae0::/28fc4d:aef:ffff:ffff:ffff:ffff:ffff:ffff
176fc4d:af0::/28fc4d:aff:ffff:ffff:ffff:ffff:ffff:ffff
177fc4d:b00::/28fc4d:b0f:ffff:ffff:ffff:ffff:ffff:ffff
178fc4d:b10::/28fc4d:b1f:ffff:ffff:ffff:ffff:ffff:ffff
179fc4d:b20::/28fc4d:b2f:ffff:ffff:ffff:ffff:ffff:ffff
180fc4d:b30::/28fc4d:b3f:ffff:ffff:ffff:ffff:ffff:ffff
181fc4d:b40::/28fc4d:b4f:ffff:ffff:ffff:ffff:ffff:ffff
182fc4d:b50::/28fc4d:b5f:ffff:ffff:ffff:ffff:ffff:ffff
183fc4d:b60::/28fc4d:b6f:ffff:ffff:ffff:ffff:ffff:ffff
184fc4d:b70::/28fc4d:b7f:ffff:ffff:ffff:ffff:ffff:ffff
185fc4d:b80::/28fc4d:b8f:ffff:ffff:ffff:ffff:ffff:ffff
186fc4d:b90::/28fc4d:b9f:ffff:ffff:ffff:ffff:ffff:ffff
187fc4d:ba0::/28fc4d:baf:ffff:ffff:ffff:ffff:ffff:ffff
188fc4d:bb0::/28fc4d:bbf:ffff:ffff:ffff:ffff:ffff:ffff
189fc4d:bc0::/28fc4d:bcf:ffff:ffff:ffff:ffff:ffff:ffff
190fc4d:bd0::/28fc4d:bdf:ffff:ffff:ffff:ffff:ffff:ffff
191fc4d:be0::/28fc4d:bef:ffff:ffff:ffff:ffff:ffff:ffff
192fc4d:bf0::/28fc4d:bff:ffff:ffff:ffff:ffff:ffff:ffff
193fc4d:c00::/28fc4d:c0f:ffff:ffff:ffff:ffff:ffff:ffff
194fc4d:c10::/28fc4d:c1f:ffff:ffff:ffff:ffff:ffff:ffff
195fc4d:c20::/28fc4d:c2f:ffff:ffff:ffff:ffff:ffff:ffff
196fc4d:c30::/28fc4d:c3f:ffff:ffff:ffff:ffff:ffff:ffff
197fc4d:c40::/28fc4d:c4f:ffff:ffff:ffff:ffff:ffff:ffff
198fc4d:c50::/28fc4d:c5f:ffff:ffff:ffff:ffff:ffff:ffff
199fc4d:c60::/28fc4d:c6f:ffff:ffff:ffff:ffff:ffff:ffff
200fc4d:c70::/28fc4d:c7f:ffff:ffff:ffff:ffff:ffff:ffff
201fc4d:c80::/28fc4d:c8f:ffff:ffff:ffff:ffff:ffff:ffff
202fc4d:c90::/28fc4d:c9f:ffff:ffff:ffff:ffff:ffff:ffff
203fc4d:ca0::/28fc4d:caf:ffff:ffff:ffff:ffff:ffff:ffff
204fc4d:cb0::/28fc4d:cbf:ffff:ffff:ffff:ffff:ffff:ffff
205fc4d:cc0::/28fc4d:ccf:ffff:ffff:ffff:ffff:ffff:ffff
206fc4d:cd0::/28fc4d:cdf:ffff:ffff:ffff:ffff:ffff:ffff
207fc4d:ce0::/28fc4d:cef:ffff:ffff:ffff:ffff:ffff:ffff
208fc4d:cf0::/28fc4d:cff:ffff:ffff:ffff:ffff:ffff:ffff
209fc4d:d00::/28fc4d:d0f:ffff:ffff:ffff:ffff:ffff:ffff
210fc4d:d10::/28fc4d:d1f:ffff:ffff:ffff:ffff:ffff:ffff
211fc4d:d20::/28fc4d:d2f:ffff:ffff:ffff:ffff:ffff:ffff
212fc4d:d30::/28fc4d:d3f:ffff:ffff:ffff:ffff:ffff:ffff
213fc4d:d40::/28fc4d:d4f:ffff:ffff:ffff:ffff:ffff:ffff
214fc4d:d50::/28fc4d:d5f:ffff:ffff:ffff:ffff:ffff:ffff
215fc4d:d60::/28fc4d:d6f:ffff:ffff:ffff:ffff:ffff:ffff
216fc4d:d70::/28fc4d:d7f:ffff:ffff:ffff:ffff:ffff:ffff
217fc4d:d80::/28fc4d:d8f:ffff:ffff:ffff:ffff:ffff:ffff
218fc4d:d90::/28fc4d:d9f:ffff:ffff:ffff:ffff:ffff:ffff
219fc4d:da0::/28fc4d:daf:ffff:ffff:ffff:ffff:ffff:ffff
220fc4d:db0::/28fc4d:dbf:ffff:ffff:ffff:ffff:ffff:ffff
221fc4d:dc0::/28fc4d:dcf:ffff:ffff:ffff:ffff:ffff:ffff
222fc4d:dd0::/28fc4d:ddf:ffff:ffff:ffff:ffff:ffff:ffff
223fc4d:de0::/28fc4d:def:ffff:ffff:ffff:ffff:ffff:ffff
224fc4d:df0::/28fc4d:dff:ffff:ffff:ffff:ffff:ffff:ffff
225fc4d:e00::/28fc4d:e0f:ffff:ffff:ffff:ffff:ffff:ffff
226fc4d:e10::/28fc4d:e1f:ffff:ffff:ffff:ffff:ffff:ffff
227fc4d:e20::/28fc4d:e2f:ffff:ffff:ffff:ffff:ffff:ffff
228fc4d:e30::/28fc4d:e3f:ffff:ffff:ffff:ffff:ffff:ffff
229fc4d:e40::/28fc4d:e4f:ffff:ffff:ffff:ffff:ffff:ffff
230fc4d:e50::/28fc4d:e5f:ffff:ffff:ffff:ffff:ffff:ffff
231fc4d:e60::/28fc4d:e6f:ffff:ffff:ffff:ffff:ffff:ffff
232fc4d:e70::/28fc4d:e7f:ffff:ffff:ffff:ffff:ffff:ffff
233fc4d:e80::/28fc4d:e8f:ffff:ffff:ffff:ffff:ffff:ffff
234fc4d:e90::/28fc4d:e9f:ffff:ffff:ffff:ffff:ffff:ffff
235fc4d:ea0::/28fc4d:eaf:ffff:ffff:ffff:ffff:ffff:ffff
236fc4d:eb0::/28fc4d:ebf:ffff:ffff:ffff:ffff:ffff:ffff
237fc4d:ec0::/28fc4d:ecf:ffff:ffff:ffff:ffff:ffff:ffff
238fc4d:ed0::/28fc4d:edf:ffff:ffff:ffff:ffff:ffff:ffff
239fc4d:ee0::/28fc4d:eef:ffff:ffff:ffff:ffff:ffff:ffff
240fc4d:ef0::/28fc4d:eff:ffff:ffff:ffff:ffff:ffff:ffff
241fc4d:f00::/28fc4d:f0f:ffff:ffff:ffff:ffff:ffff:ffff
242fc4d:f10::/28fc4d:f1f:ffff:ffff:ffff:ffff:ffff:ffff
243fc4d:f20::/28fc4d:f2f:ffff:ffff:ffff:ffff:ffff:ffff
244fc4d:f30::/28fc4d:f3f:ffff:ffff:ffff:ffff:ffff:ffff
245fc4d:f40::/28fc4d:f4f:ffff:ffff:ffff:ffff:ffff:ffff
246fc4d:f50::/28fc4d:f5f:ffff:ffff:ffff:ffff:ffff:ffff
247fc4d:f60::/28fc4d:f6f:ffff:ffff:ffff:ffff:ffff:ffff
248fc4d:f70::/28fc4d:f7f:ffff:ffff:ffff:ffff:ffff:ffff
249fc4d:f80::/28fc4d:f8f:ffff:ffff:ffff:ffff:ffff:ffff
250fc4d:f90::/28fc4d:f9f:ffff:ffff:ffff:ffff:ffff:ffff
251fc4d:fa0::/28fc4d:faf:ffff:ffff:ffff:ffff:ffff:ffff
252fc4d:fb0::/28fc4d:fbf:ffff:ffff:ffff:ffff:ffff:ffff
253fc4d:fc0::/28fc4d:fcf:ffff:ffff:ffff:ffff:ffff:ffff
254fc4d:fd0::/28fc4d:fdf:ffff:ffff:ffff:ffff:ffff:ffff
255fc4d:fe0::/28fc4d:fef:ffff:ffff:ffff:ffff:ffff:ffff
256fc4d:ff0::/28fc4d: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.