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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
fc7f::/16
First address
fc7f::
Last address
fc7f: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
fc7f:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
f.7.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)

fc7f::/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
1fc7f::/28fc7f:f:ffff:ffff:ffff:ffff:ffff:ffff
2fc7f:10::/28fc7f:1f:ffff:ffff:ffff:ffff:ffff:ffff
3fc7f:20::/28fc7f:2f:ffff:ffff:ffff:ffff:ffff:ffff
4fc7f:30::/28fc7f:3f:ffff:ffff:ffff:ffff:ffff:ffff
5fc7f:40::/28fc7f:4f:ffff:ffff:ffff:ffff:ffff:ffff
6fc7f:50::/28fc7f:5f:ffff:ffff:ffff:ffff:ffff:ffff
7fc7f:60::/28fc7f:6f:ffff:ffff:ffff:ffff:ffff:ffff
8fc7f:70::/28fc7f:7f:ffff:ffff:ffff:ffff:ffff:ffff
9fc7f:80::/28fc7f:8f:ffff:ffff:ffff:ffff:ffff:ffff
10fc7f:90::/28fc7f:9f:ffff:ffff:ffff:ffff:ffff:ffff
11fc7f:a0::/28fc7f:af:ffff:ffff:ffff:ffff:ffff:ffff
12fc7f:b0::/28fc7f:bf:ffff:ffff:ffff:ffff:ffff:ffff
13fc7f:c0::/28fc7f:cf:ffff:ffff:ffff:ffff:ffff:ffff
14fc7f:d0::/28fc7f:df:ffff:ffff:ffff:ffff:ffff:ffff
15fc7f:e0::/28fc7f:ef:ffff:ffff:ffff:ffff:ffff:ffff
16fc7f:f0::/28fc7f:ff:ffff:ffff:ffff:ffff:ffff:ffff
17fc7f:100::/28fc7f:10f:ffff:ffff:ffff:ffff:ffff:ffff
18fc7f:110::/28fc7f:11f:ffff:ffff:ffff:ffff:ffff:ffff
19fc7f:120::/28fc7f:12f:ffff:ffff:ffff:ffff:ffff:ffff
20fc7f:130::/28fc7f:13f:ffff:ffff:ffff:ffff:ffff:ffff
21fc7f:140::/28fc7f:14f:ffff:ffff:ffff:ffff:ffff:ffff
22fc7f:150::/28fc7f:15f:ffff:ffff:ffff:ffff:ffff:ffff
23fc7f:160::/28fc7f:16f:ffff:ffff:ffff:ffff:ffff:ffff
24fc7f:170::/28fc7f:17f:ffff:ffff:ffff:ffff:ffff:ffff
25fc7f:180::/28fc7f:18f:ffff:ffff:ffff:ffff:ffff:ffff
26fc7f:190::/28fc7f:19f:ffff:ffff:ffff:ffff:ffff:ffff
27fc7f:1a0::/28fc7f:1af:ffff:ffff:ffff:ffff:ffff:ffff
28fc7f:1b0::/28fc7f:1bf:ffff:ffff:ffff:ffff:ffff:ffff
29fc7f:1c0::/28fc7f:1cf:ffff:ffff:ffff:ffff:ffff:ffff
30fc7f:1d0::/28fc7f:1df:ffff:ffff:ffff:ffff:ffff:ffff
31fc7f:1e0::/28fc7f:1ef:ffff:ffff:ffff:ffff:ffff:ffff
32fc7f:1f0::/28fc7f:1ff:ffff:ffff:ffff:ffff:ffff:ffff
33fc7f:200::/28fc7f:20f:ffff:ffff:ffff:ffff:ffff:ffff
34fc7f:210::/28fc7f:21f:ffff:ffff:ffff:ffff:ffff:ffff
35fc7f:220::/28fc7f:22f:ffff:ffff:ffff:ffff:ffff:ffff
36fc7f:230::/28fc7f:23f:ffff:ffff:ffff:ffff:ffff:ffff
37fc7f:240::/28fc7f:24f:ffff:ffff:ffff:ffff:ffff:ffff
38fc7f:250::/28fc7f:25f:ffff:ffff:ffff:ffff:ffff:ffff
39fc7f:260::/28fc7f:26f:ffff:ffff:ffff:ffff:ffff:ffff
40fc7f:270::/28fc7f:27f:ffff:ffff:ffff:ffff:ffff:ffff
41fc7f:280::/28fc7f:28f:ffff:ffff:ffff:ffff:ffff:ffff
42fc7f:290::/28fc7f:29f:ffff:ffff:ffff:ffff:ffff:ffff
43fc7f:2a0::/28fc7f:2af:ffff:ffff:ffff:ffff:ffff:ffff
44fc7f:2b0::/28fc7f:2bf:ffff:ffff:ffff:ffff:ffff:ffff
45fc7f:2c0::/28fc7f:2cf:ffff:ffff:ffff:ffff:ffff:ffff
46fc7f:2d0::/28fc7f:2df:ffff:ffff:ffff:ffff:ffff:ffff
47fc7f:2e0::/28fc7f:2ef:ffff:ffff:ffff:ffff:ffff:ffff
48fc7f:2f0::/28fc7f:2ff:ffff:ffff:ffff:ffff:ffff:ffff
49fc7f:300::/28fc7f:30f:ffff:ffff:ffff:ffff:ffff:ffff
50fc7f:310::/28fc7f:31f:ffff:ffff:ffff:ffff:ffff:ffff
51fc7f:320::/28fc7f:32f:ffff:ffff:ffff:ffff:ffff:ffff
52fc7f:330::/28fc7f:33f:ffff:ffff:ffff:ffff:ffff:ffff
53fc7f:340::/28fc7f:34f:ffff:ffff:ffff:ffff:ffff:ffff
54fc7f:350::/28fc7f:35f:ffff:ffff:ffff:ffff:ffff:ffff
55fc7f:360::/28fc7f:36f:ffff:ffff:ffff:ffff:ffff:ffff
56fc7f:370::/28fc7f:37f:ffff:ffff:ffff:ffff:ffff:ffff
57fc7f:380::/28fc7f:38f:ffff:ffff:ffff:ffff:ffff:ffff
58fc7f:390::/28fc7f:39f:ffff:ffff:ffff:ffff:ffff:ffff
59fc7f:3a0::/28fc7f:3af:ffff:ffff:ffff:ffff:ffff:ffff
60fc7f:3b0::/28fc7f:3bf:ffff:ffff:ffff:ffff:ffff:ffff
61fc7f:3c0::/28fc7f:3cf:ffff:ffff:ffff:ffff:ffff:ffff
62fc7f:3d0::/28fc7f:3df:ffff:ffff:ffff:ffff:ffff:ffff
63fc7f:3e0::/28fc7f:3ef:ffff:ffff:ffff:ffff:ffff:ffff
64fc7f:3f0::/28fc7f:3ff:ffff:ffff:ffff:ffff:ffff:ffff
65fc7f:400::/28fc7f:40f:ffff:ffff:ffff:ffff:ffff:ffff
66fc7f:410::/28fc7f:41f:ffff:ffff:ffff:ffff:ffff:ffff
67fc7f:420::/28fc7f:42f:ffff:ffff:ffff:ffff:ffff:ffff
68fc7f:430::/28fc7f:43f:ffff:ffff:ffff:ffff:ffff:ffff
69fc7f:440::/28fc7f:44f:ffff:ffff:ffff:ffff:ffff:ffff
70fc7f:450::/28fc7f:45f:ffff:ffff:ffff:ffff:ffff:ffff
71fc7f:460::/28fc7f:46f:ffff:ffff:ffff:ffff:ffff:ffff
72fc7f:470::/28fc7f:47f:ffff:ffff:ffff:ffff:ffff:ffff
73fc7f:480::/28fc7f:48f:ffff:ffff:ffff:ffff:ffff:ffff
74fc7f:490::/28fc7f:49f:ffff:ffff:ffff:ffff:ffff:ffff
75fc7f:4a0::/28fc7f:4af:ffff:ffff:ffff:ffff:ffff:ffff
76fc7f:4b0::/28fc7f:4bf:ffff:ffff:ffff:ffff:ffff:ffff
77fc7f:4c0::/28fc7f:4cf:ffff:ffff:ffff:ffff:ffff:ffff
78fc7f:4d0::/28fc7f:4df:ffff:ffff:ffff:ffff:ffff:ffff
79fc7f:4e0::/28fc7f:4ef:ffff:ffff:ffff:ffff:ffff:ffff
80fc7f:4f0::/28fc7f:4ff:ffff:ffff:ffff:ffff:ffff:ffff
81fc7f:500::/28fc7f:50f:ffff:ffff:ffff:ffff:ffff:ffff
82fc7f:510::/28fc7f:51f:ffff:ffff:ffff:ffff:ffff:ffff
83fc7f:520::/28fc7f:52f:ffff:ffff:ffff:ffff:ffff:ffff
84fc7f:530::/28fc7f:53f:ffff:ffff:ffff:ffff:ffff:ffff
85fc7f:540::/28fc7f:54f:ffff:ffff:ffff:ffff:ffff:ffff
86fc7f:550::/28fc7f:55f:ffff:ffff:ffff:ffff:ffff:ffff
87fc7f:560::/28fc7f:56f:ffff:ffff:ffff:ffff:ffff:ffff
88fc7f:570::/28fc7f:57f:ffff:ffff:ffff:ffff:ffff:ffff
89fc7f:580::/28fc7f:58f:ffff:ffff:ffff:ffff:ffff:ffff
90fc7f:590::/28fc7f:59f:ffff:ffff:ffff:ffff:ffff:ffff
91fc7f:5a0::/28fc7f:5af:ffff:ffff:ffff:ffff:ffff:ffff
92fc7f:5b0::/28fc7f:5bf:ffff:ffff:ffff:ffff:ffff:ffff
93fc7f:5c0::/28fc7f:5cf:ffff:ffff:ffff:ffff:ffff:ffff
94fc7f:5d0::/28fc7f:5df:ffff:ffff:ffff:ffff:ffff:ffff
95fc7f:5e0::/28fc7f:5ef:ffff:ffff:ffff:ffff:ffff:ffff
96fc7f:5f0::/28fc7f:5ff:ffff:ffff:ffff:ffff:ffff:ffff
97fc7f:600::/28fc7f:60f:ffff:ffff:ffff:ffff:ffff:ffff
98fc7f:610::/28fc7f:61f:ffff:ffff:ffff:ffff:ffff:ffff
99fc7f:620::/28fc7f:62f:ffff:ffff:ffff:ffff:ffff:ffff
100fc7f:630::/28fc7f:63f:ffff:ffff:ffff:ffff:ffff:ffff
101fc7f:640::/28fc7f:64f:ffff:ffff:ffff:ffff:ffff:ffff
102fc7f:650::/28fc7f:65f:ffff:ffff:ffff:ffff:ffff:ffff
103fc7f:660::/28fc7f:66f:ffff:ffff:ffff:ffff:ffff:ffff
104fc7f:670::/28fc7f:67f:ffff:ffff:ffff:ffff:ffff:ffff
105fc7f:680::/28fc7f:68f:ffff:ffff:ffff:ffff:ffff:ffff
106fc7f:690::/28fc7f:69f:ffff:ffff:ffff:ffff:ffff:ffff
107fc7f:6a0::/28fc7f:6af:ffff:ffff:ffff:ffff:ffff:ffff
108fc7f:6b0::/28fc7f:6bf:ffff:ffff:ffff:ffff:ffff:ffff
109fc7f:6c0::/28fc7f:6cf:ffff:ffff:ffff:ffff:ffff:ffff
110fc7f:6d0::/28fc7f:6df:ffff:ffff:ffff:ffff:ffff:ffff
111fc7f:6e0::/28fc7f:6ef:ffff:ffff:ffff:ffff:ffff:ffff
112fc7f:6f0::/28fc7f:6ff:ffff:ffff:ffff:ffff:ffff:ffff
113fc7f:700::/28fc7f:70f:ffff:ffff:ffff:ffff:ffff:ffff
114fc7f:710::/28fc7f:71f:ffff:ffff:ffff:ffff:ffff:ffff
115fc7f:720::/28fc7f:72f:ffff:ffff:ffff:ffff:ffff:ffff
116fc7f:730::/28fc7f:73f:ffff:ffff:ffff:ffff:ffff:ffff
117fc7f:740::/28fc7f:74f:ffff:ffff:ffff:ffff:ffff:ffff
118fc7f:750::/28fc7f:75f:ffff:ffff:ffff:ffff:ffff:ffff
119fc7f:760::/28fc7f:76f:ffff:ffff:ffff:ffff:ffff:ffff
120fc7f:770::/28fc7f:77f:ffff:ffff:ffff:ffff:ffff:ffff
121fc7f:780::/28fc7f:78f:ffff:ffff:ffff:ffff:ffff:ffff
122fc7f:790::/28fc7f:79f:ffff:ffff:ffff:ffff:ffff:ffff
123fc7f:7a0::/28fc7f:7af:ffff:ffff:ffff:ffff:ffff:ffff
124fc7f:7b0::/28fc7f:7bf:ffff:ffff:ffff:ffff:ffff:ffff
125fc7f:7c0::/28fc7f:7cf:ffff:ffff:ffff:ffff:ffff:ffff
126fc7f:7d0::/28fc7f:7df:ffff:ffff:ffff:ffff:ffff:ffff
127fc7f:7e0::/28fc7f:7ef:ffff:ffff:ffff:ffff:ffff:ffff
128fc7f:7f0::/28fc7f:7ff:ffff:ffff:ffff:ffff:ffff:ffff
129fc7f:800::/28fc7f:80f:ffff:ffff:ffff:ffff:ffff:ffff
130fc7f:810::/28fc7f:81f:ffff:ffff:ffff:ffff:ffff:ffff
131fc7f:820::/28fc7f:82f:ffff:ffff:ffff:ffff:ffff:ffff
132fc7f:830::/28fc7f:83f:ffff:ffff:ffff:ffff:ffff:ffff
133fc7f:840::/28fc7f:84f:ffff:ffff:ffff:ffff:ffff:ffff
134fc7f:850::/28fc7f:85f:ffff:ffff:ffff:ffff:ffff:ffff
135fc7f:860::/28fc7f:86f:ffff:ffff:ffff:ffff:ffff:ffff
136fc7f:870::/28fc7f:87f:ffff:ffff:ffff:ffff:ffff:ffff
137fc7f:880::/28fc7f:88f:ffff:ffff:ffff:ffff:ffff:ffff
138fc7f:890::/28fc7f:89f:ffff:ffff:ffff:ffff:ffff:ffff
139fc7f:8a0::/28fc7f:8af:ffff:ffff:ffff:ffff:ffff:ffff
140fc7f:8b0::/28fc7f:8bf:ffff:ffff:ffff:ffff:ffff:ffff
141fc7f:8c0::/28fc7f:8cf:ffff:ffff:ffff:ffff:ffff:ffff
142fc7f:8d0::/28fc7f:8df:ffff:ffff:ffff:ffff:ffff:ffff
143fc7f:8e0::/28fc7f:8ef:ffff:ffff:ffff:ffff:ffff:ffff
144fc7f:8f0::/28fc7f:8ff:ffff:ffff:ffff:ffff:ffff:ffff
145fc7f:900::/28fc7f:90f:ffff:ffff:ffff:ffff:ffff:ffff
146fc7f:910::/28fc7f:91f:ffff:ffff:ffff:ffff:ffff:ffff
147fc7f:920::/28fc7f:92f:ffff:ffff:ffff:ffff:ffff:ffff
148fc7f:930::/28fc7f:93f:ffff:ffff:ffff:ffff:ffff:ffff
149fc7f:940::/28fc7f:94f:ffff:ffff:ffff:ffff:ffff:ffff
150fc7f:950::/28fc7f:95f:ffff:ffff:ffff:ffff:ffff:ffff
151fc7f:960::/28fc7f:96f:ffff:ffff:ffff:ffff:ffff:ffff
152fc7f:970::/28fc7f:97f:ffff:ffff:ffff:ffff:ffff:ffff
153fc7f:980::/28fc7f:98f:ffff:ffff:ffff:ffff:ffff:ffff
154fc7f:990::/28fc7f:99f:ffff:ffff:ffff:ffff:ffff:ffff
155fc7f:9a0::/28fc7f:9af:ffff:ffff:ffff:ffff:ffff:ffff
156fc7f:9b0::/28fc7f:9bf:ffff:ffff:ffff:ffff:ffff:ffff
157fc7f:9c0::/28fc7f:9cf:ffff:ffff:ffff:ffff:ffff:ffff
158fc7f:9d0::/28fc7f:9df:ffff:ffff:ffff:ffff:ffff:ffff
159fc7f:9e0::/28fc7f:9ef:ffff:ffff:ffff:ffff:ffff:ffff
160fc7f:9f0::/28fc7f:9ff:ffff:ffff:ffff:ffff:ffff:ffff
161fc7f:a00::/28fc7f:a0f:ffff:ffff:ffff:ffff:ffff:ffff
162fc7f:a10::/28fc7f:a1f:ffff:ffff:ffff:ffff:ffff:ffff
163fc7f:a20::/28fc7f:a2f:ffff:ffff:ffff:ffff:ffff:ffff
164fc7f:a30::/28fc7f:a3f:ffff:ffff:ffff:ffff:ffff:ffff
165fc7f:a40::/28fc7f:a4f:ffff:ffff:ffff:ffff:ffff:ffff
166fc7f:a50::/28fc7f:a5f:ffff:ffff:ffff:ffff:ffff:ffff
167fc7f:a60::/28fc7f:a6f:ffff:ffff:ffff:ffff:ffff:ffff
168fc7f:a70::/28fc7f:a7f:ffff:ffff:ffff:ffff:ffff:ffff
169fc7f:a80::/28fc7f:a8f:ffff:ffff:ffff:ffff:ffff:ffff
170fc7f:a90::/28fc7f:a9f:ffff:ffff:ffff:ffff:ffff:ffff
171fc7f:aa0::/28fc7f:aaf:ffff:ffff:ffff:ffff:ffff:ffff
172fc7f:ab0::/28fc7f:abf:ffff:ffff:ffff:ffff:ffff:ffff
173fc7f:ac0::/28fc7f:acf:ffff:ffff:ffff:ffff:ffff:ffff
174fc7f:ad0::/28fc7f:adf:ffff:ffff:ffff:ffff:ffff:ffff
175fc7f:ae0::/28fc7f:aef:ffff:ffff:ffff:ffff:ffff:ffff
176fc7f:af0::/28fc7f:aff:ffff:ffff:ffff:ffff:ffff:ffff
177fc7f:b00::/28fc7f:b0f:ffff:ffff:ffff:ffff:ffff:ffff
178fc7f:b10::/28fc7f:b1f:ffff:ffff:ffff:ffff:ffff:ffff
179fc7f:b20::/28fc7f:b2f:ffff:ffff:ffff:ffff:ffff:ffff
180fc7f:b30::/28fc7f:b3f:ffff:ffff:ffff:ffff:ffff:ffff
181fc7f:b40::/28fc7f:b4f:ffff:ffff:ffff:ffff:ffff:ffff
182fc7f:b50::/28fc7f:b5f:ffff:ffff:ffff:ffff:ffff:ffff
183fc7f:b60::/28fc7f:b6f:ffff:ffff:ffff:ffff:ffff:ffff
184fc7f:b70::/28fc7f:b7f:ffff:ffff:ffff:ffff:ffff:ffff
185fc7f:b80::/28fc7f:b8f:ffff:ffff:ffff:ffff:ffff:ffff
186fc7f:b90::/28fc7f:b9f:ffff:ffff:ffff:ffff:ffff:ffff
187fc7f:ba0::/28fc7f:baf:ffff:ffff:ffff:ffff:ffff:ffff
188fc7f:bb0::/28fc7f:bbf:ffff:ffff:ffff:ffff:ffff:ffff
189fc7f:bc0::/28fc7f:bcf:ffff:ffff:ffff:ffff:ffff:ffff
190fc7f:bd0::/28fc7f:bdf:ffff:ffff:ffff:ffff:ffff:ffff
191fc7f:be0::/28fc7f:bef:ffff:ffff:ffff:ffff:ffff:ffff
192fc7f:bf0::/28fc7f:bff:ffff:ffff:ffff:ffff:ffff:ffff
193fc7f:c00::/28fc7f:c0f:ffff:ffff:ffff:ffff:ffff:ffff
194fc7f:c10::/28fc7f:c1f:ffff:ffff:ffff:ffff:ffff:ffff
195fc7f:c20::/28fc7f:c2f:ffff:ffff:ffff:ffff:ffff:ffff
196fc7f:c30::/28fc7f:c3f:ffff:ffff:ffff:ffff:ffff:ffff
197fc7f:c40::/28fc7f:c4f:ffff:ffff:ffff:ffff:ffff:ffff
198fc7f:c50::/28fc7f:c5f:ffff:ffff:ffff:ffff:ffff:ffff
199fc7f:c60::/28fc7f:c6f:ffff:ffff:ffff:ffff:ffff:ffff
200fc7f:c70::/28fc7f:c7f:ffff:ffff:ffff:ffff:ffff:ffff
201fc7f:c80::/28fc7f:c8f:ffff:ffff:ffff:ffff:ffff:ffff
202fc7f:c90::/28fc7f:c9f:ffff:ffff:ffff:ffff:ffff:ffff
203fc7f:ca0::/28fc7f:caf:ffff:ffff:ffff:ffff:ffff:ffff
204fc7f:cb0::/28fc7f:cbf:ffff:ffff:ffff:ffff:ffff:ffff
205fc7f:cc0::/28fc7f:ccf:ffff:ffff:ffff:ffff:ffff:ffff
206fc7f:cd0::/28fc7f:cdf:ffff:ffff:ffff:ffff:ffff:ffff
207fc7f:ce0::/28fc7f:cef:ffff:ffff:ffff:ffff:ffff:ffff
208fc7f:cf0::/28fc7f:cff:ffff:ffff:ffff:ffff:ffff:ffff
209fc7f:d00::/28fc7f:d0f:ffff:ffff:ffff:ffff:ffff:ffff
210fc7f:d10::/28fc7f:d1f:ffff:ffff:ffff:ffff:ffff:ffff
211fc7f:d20::/28fc7f:d2f:ffff:ffff:ffff:ffff:ffff:ffff
212fc7f:d30::/28fc7f:d3f:ffff:ffff:ffff:ffff:ffff:ffff
213fc7f:d40::/28fc7f:d4f:ffff:ffff:ffff:ffff:ffff:ffff
214fc7f:d50::/28fc7f:d5f:ffff:ffff:ffff:ffff:ffff:ffff
215fc7f:d60::/28fc7f:d6f:ffff:ffff:ffff:ffff:ffff:ffff
216fc7f:d70::/28fc7f:d7f:ffff:ffff:ffff:ffff:ffff:ffff
217fc7f:d80::/28fc7f:d8f:ffff:ffff:ffff:ffff:ffff:ffff
218fc7f:d90::/28fc7f:d9f:ffff:ffff:ffff:ffff:ffff:ffff
219fc7f:da0::/28fc7f:daf:ffff:ffff:ffff:ffff:ffff:ffff
220fc7f:db0::/28fc7f:dbf:ffff:ffff:ffff:ffff:ffff:ffff
221fc7f:dc0::/28fc7f:dcf:ffff:ffff:ffff:ffff:ffff:ffff
222fc7f:dd0::/28fc7f:ddf:ffff:ffff:ffff:ffff:ffff:ffff
223fc7f:de0::/28fc7f:def:ffff:ffff:ffff:ffff:ffff:ffff
224fc7f:df0::/28fc7f:dff:ffff:ffff:ffff:ffff:ffff:ffff
225fc7f:e00::/28fc7f:e0f:ffff:ffff:ffff:ffff:ffff:ffff
226fc7f:e10::/28fc7f:e1f:ffff:ffff:ffff:ffff:ffff:ffff
227fc7f:e20::/28fc7f:e2f:ffff:ffff:ffff:ffff:ffff:ffff
228fc7f:e30::/28fc7f:e3f:ffff:ffff:ffff:ffff:ffff:ffff
229fc7f:e40::/28fc7f:e4f:ffff:ffff:ffff:ffff:ffff:ffff
230fc7f:e50::/28fc7f:e5f:ffff:ffff:ffff:ffff:ffff:ffff
231fc7f:e60::/28fc7f:e6f:ffff:ffff:ffff:ffff:ffff:ffff
232fc7f:e70::/28fc7f:e7f:ffff:ffff:ffff:ffff:ffff:ffff
233fc7f:e80::/28fc7f:e8f:ffff:ffff:ffff:ffff:ffff:ffff
234fc7f:e90::/28fc7f:e9f:ffff:ffff:ffff:ffff:ffff:ffff
235fc7f:ea0::/28fc7f:eaf:ffff:ffff:ffff:ffff:ffff:ffff
236fc7f:eb0::/28fc7f:ebf:ffff:ffff:ffff:ffff:ffff:ffff
237fc7f:ec0::/28fc7f:ecf:ffff:ffff:ffff:ffff:ffff:ffff
238fc7f:ed0::/28fc7f:edf:ffff:ffff:ffff:ffff:ffff:ffff
239fc7f:ee0::/28fc7f:eef:ffff:ffff:ffff:ffff:ffff:ffff
240fc7f:ef0::/28fc7f:eff:ffff:ffff:ffff:ffff:ffff:ffff
241fc7f:f00::/28fc7f:f0f:ffff:ffff:ffff:ffff:ffff:ffff
242fc7f:f10::/28fc7f:f1f:ffff:ffff:ffff:ffff:ffff:ffff
243fc7f:f20::/28fc7f:f2f:ffff:ffff:ffff:ffff:ffff:ffff
244fc7f:f30::/28fc7f:f3f:ffff:ffff:ffff:ffff:ffff:ffff
245fc7f:f40::/28fc7f:f4f:ffff:ffff:ffff:ffff:ffff:ffff
246fc7f:f50::/28fc7f:f5f:ffff:ffff:ffff:ffff:ffff:ffff
247fc7f:f60::/28fc7f:f6f:ffff:ffff:ffff:ffff:ffff:ffff
248fc7f:f70::/28fc7f:f7f:ffff:ffff:ffff:ffff:ffff:ffff
249fc7f:f80::/28fc7f:f8f:ffff:ffff:ffff:ffff:ffff:ffff
250fc7f:f90::/28fc7f:f9f:ffff:ffff:ffff:ffff:ffff:ffff
251fc7f:fa0::/28fc7f:faf:ffff:ffff:ffff:ffff:ffff:ffff
252fc7f:fb0::/28fc7f:fbf:ffff:ffff:ffff:ffff:ffff:ffff
253fc7f:fc0::/28fc7f:fcf:ffff:ffff:ffff:ffff:ffff:ffff
254fc7f:fd0::/28fc7f:fdf:ffff:ffff:ffff:ffff:ffff:ffff
255fc7f:fe0::/28fc7f:fef:ffff:ffff:ffff:ffff:ffff:ffff
256fc7f:ff0::/28fc7f: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.