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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/18
Addresses2^110
/64 networks2^46
Network
fc7c::/18
First address
fc7c::
Last address
fc7c:3fff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
1,298,074,214,633,706,907,132,624,082,305,024 (2^110)
/64 networks (LANs)
70,368,744,177,664 (2^46)
Full form
fc7c:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zones
0.c.7.c.f.ip6.arpa
1.c.7.c.f.ip6.arpa
2.c.7.c.f.ip6.arpa
3.c.7.c.f.ip6.arpa
/18 is not on a 4-bit boundary, so it takes 4 /20 zones.
Split into smaller subnets/28
/19 (2)/20 (4)/21 (8)/22 (16)/24 (64)/28 (1,024)/32 (16,384)

fc7c::/18 makes 1,024 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
1fc7c::/28fc7c:f:ffff:ffff:ffff:ffff:ffff:ffff
2fc7c:10::/28fc7c:1f:ffff:ffff:ffff:ffff:ffff:ffff
3fc7c:20::/28fc7c:2f:ffff:ffff:ffff:ffff:ffff:ffff
4fc7c:30::/28fc7c:3f:ffff:ffff:ffff:ffff:ffff:ffff
5fc7c:40::/28fc7c:4f:ffff:ffff:ffff:ffff:ffff:ffff
6fc7c:50::/28fc7c:5f:ffff:ffff:ffff:ffff:ffff:ffff
7fc7c:60::/28fc7c:6f:ffff:ffff:ffff:ffff:ffff:ffff
8fc7c:70::/28fc7c:7f:ffff:ffff:ffff:ffff:ffff:ffff
9fc7c:80::/28fc7c:8f:ffff:ffff:ffff:ffff:ffff:ffff
10fc7c:90::/28fc7c:9f:ffff:ffff:ffff:ffff:ffff:ffff
11fc7c:a0::/28fc7c:af:ffff:ffff:ffff:ffff:ffff:ffff
12fc7c:b0::/28fc7c:bf:ffff:ffff:ffff:ffff:ffff:ffff
13fc7c:c0::/28fc7c:cf:ffff:ffff:ffff:ffff:ffff:ffff
14fc7c:d0::/28fc7c:df:ffff:ffff:ffff:ffff:ffff:ffff
15fc7c:e0::/28fc7c:ef:ffff:ffff:ffff:ffff:ffff:ffff
16fc7c:f0::/28fc7c:ff:ffff:ffff:ffff:ffff:ffff:ffff
17fc7c:100::/28fc7c:10f:ffff:ffff:ffff:ffff:ffff:ffff
18fc7c:110::/28fc7c:11f:ffff:ffff:ffff:ffff:ffff:ffff
19fc7c:120::/28fc7c:12f:ffff:ffff:ffff:ffff:ffff:ffff
20fc7c:130::/28fc7c:13f:ffff:ffff:ffff:ffff:ffff:ffff
21fc7c:140::/28fc7c:14f:ffff:ffff:ffff:ffff:ffff:ffff
22fc7c:150::/28fc7c:15f:ffff:ffff:ffff:ffff:ffff:ffff
23fc7c:160::/28fc7c:16f:ffff:ffff:ffff:ffff:ffff:ffff
24fc7c:170::/28fc7c:17f:ffff:ffff:ffff:ffff:ffff:ffff
25fc7c:180::/28fc7c:18f:ffff:ffff:ffff:ffff:ffff:ffff
26fc7c:190::/28fc7c:19f:ffff:ffff:ffff:ffff:ffff:ffff
27fc7c:1a0::/28fc7c:1af:ffff:ffff:ffff:ffff:ffff:ffff
28fc7c:1b0::/28fc7c:1bf:ffff:ffff:ffff:ffff:ffff:ffff
29fc7c:1c0::/28fc7c:1cf:ffff:ffff:ffff:ffff:ffff:ffff
30fc7c:1d0::/28fc7c:1df:ffff:ffff:ffff:ffff:ffff:ffff
31fc7c:1e0::/28fc7c:1ef:ffff:ffff:ffff:ffff:ffff:ffff
32fc7c:1f0::/28fc7c:1ff:ffff:ffff:ffff:ffff:ffff:ffff
33fc7c:200::/28fc7c:20f:ffff:ffff:ffff:ffff:ffff:ffff
34fc7c:210::/28fc7c:21f:ffff:ffff:ffff:ffff:ffff:ffff
35fc7c:220::/28fc7c:22f:ffff:ffff:ffff:ffff:ffff:ffff
36fc7c:230::/28fc7c:23f:ffff:ffff:ffff:ffff:ffff:ffff
37fc7c:240::/28fc7c:24f:ffff:ffff:ffff:ffff:ffff:ffff
38fc7c:250::/28fc7c:25f:ffff:ffff:ffff:ffff:ffff:ffff
39fc7c:260::/28fc7c:26f:ffff:ffff:ffff:ffff:ffff:ffff
40fc7c:270::/28fc7c:27f:ffff:ffff:ffff:ffff:ffff:ffff
41fc7c:280::/28fc7c:28f:ffff:ffff:ffff:ffff:ffff:ffff
42fc7c:290::/28fc7c:29f:ffff:ffff:ffff:ffff:ffff:ffff
43fc7c:2a0::/28fc7c:2af:ffff:ffff:ffff:ffff:ffff:ffff
44fc7c:2b0::/28fc7c:2bf:ffff:ffff:ffff:ffff:ffff:ffff
45fc7c:2c0::/28fc7c:2cf:ffff:ffff:ffff:ffff:ffff:ffff
46fc7c:2d0::/28fc7c:2df:ffff:ffff:ffff:ffff:ffff:ffff
47fc7c:2e0::/28fc7c:2ef:ffff:ffff:ffff:ffff:ffff:ffff
48fc7c:2f0::/28fc7c:2ff:ffff:ffff:ffff:ffff:ffff:ffff
49fc7c:300::/28fc7c:30f:ffff:ffff:ffff:ffff:ffff:ffff
50fc7c:310::/28fc7c:31f:ffff:ffff:ffff:ffff:ffff:ffff
51fc7c:320::/28fc7c:32f:ffff:ffff:ffff:ffff:ffff:ffff
52fc7c:330::/28fc7c:33f:ffff:ffff:ffff:ffff:ffff:ffff
53fc7c:340::/28fc7c:34f:ffff:ffff:ffff:ffff:ffff:ffff
54fc7c:350::/28fc7c:35f:ffff:ffff:ffff:ffff:ffff:ffff
55fc7c:360::/28fc7c:36f:ffff:ffff:ffff:ffff:ffff:ffff
56fc7c:370::/28fc7c:37f:ffff:ffff:ffff:ffff:ffff:ffff
57fc7c:380::/28fc7c:38f:ffff:ffff:ffff:ffff:ffff:ffff
58fc7c:390::/28fc7c:39f:ffff:ffff:ffff:ffff:ffff:ffff
59fc7c:3a0::/28fc7c:3af:ffff:ffff:ffff:ffff:ffff:ffff
60fc7c:3b0::/28fc7c:3bf:ffff:ffff:ffff:ffff:ffff:ffff
61fc7c:3c0::/28fc7c:3cf:ffff:ffff:ffff:ffff:ffff:ffff
62fc7c:3d0::/28fc7c:3df:ffff:ffff:ffff:ffff:ffff:ffff
63fc7c:3e0::/28fc7c:3ef:ffff:ffff:ffff:ffff:ffff:ffff
64fc7c:3f0::/28fc7c:3ff:ffff:ffff:ffff:ffff:ffff:ffff
65fc7c:400::/28fc7c:40f:ffff:ffff:ffff:ffff:ffff:ffff
66fc7c:410::/28fc7c:41f:ffff:ffff:ffff:ffff:ffff:ffff
67fc7c:420::/28fc7c:42f:ffff:ffff:ffff:ffff:ffff:ffff
68fc7c:430::/28fc7c:43f:ffff:ffff:ffff:ffff:ffff:ffff
69fc7c:440::/28fc7c:44f:ffff:ffff:ffff:ffff:ffff:ffff
70fc7c:450::/28fc7c:45f:ffff:ffff:ffff:ffff:ffff:ffff
71fc7c:460::/28fc7c:46f:ffff:ffff:ffff:ffff:ffff:ffff
72fc7c:470::/28fc7c:47f:ffff:ffff:ffff:ffff:ffff:ffff
73fc7c:480::/28fc7c:48f:ffff:ffff:ffff:ffff:ffff:ffff
74fc7c:490::/28fc7c:49f:ffff:ffff:ffff:ffff:ffff:ffff
75fc7c:4a0::/28fc7c:4af:ffff:ffff:ffff:ffff:ffff:ffff
76fc7c:4b0::/28fc7c:4bf:ffff:ffff:ffff:ffff:ffff:ffff
77fc7c:4c0::/28fc7c:4cf:ffff:ffff:ffff:ffff:ffff:ffff
78fc7c:4d0::/28fc7c:4df:ffff:ffff:ffff:ffff:ffff:ffff
79fc7c:4e0::/28fc7c:4ef:ffff:ffff:ffff:ffff:ffff:ffff
80fc7c:4f0::/28fc7c:4ff:ffff:ffff:ffff:ffff:ffff:ffff
81fc7c:500::/28fc7c:50f:ffff:ffff:ffff:ffff:ffff:ffff
82fc7c:510::/28fc7c:51f:ffff:ffff:ffff:ffff:ffff:ffff
83fc7c:520::/28fc7c:52f:ffff:ffff:ffff:ffff:ffff:ffff
84fc7c:530::/28fc7c:53f:ffff:ffff:ffff:ffff:ffff:ffff
85fc7c:540::/28fc7c:54f:ffff:ffff:ffff:ffff:ffff:ffff
86fc7c:550::/28fc7c:55f:ffff:ffff:ffff:ffff:ffff:ffff
87fc7c:560::/28fc7c:56f:ffff:ffff:ffff:ffff:ffff:ffff
88fc7c:570::/28fc7c:57f:ffff:ffff:ffff:ffff:ffff:ffff
89fc7c:580::/28fc7c:58f:ffff:ffff:ffff:ffff:ffff:ffff
90fc7c:590::/28fc7c:59f:ffff:ffff:ffff:ffff:ffff:ffff
91fc7c:5a0::/28fc7c:5af:ffff:ffff:ffff:ffff:ffff:ffff
92fc7c:5b0::/28fc7c:5bf:ffff:ffff:ffff:ffff:ffff:ffff
93fc7c:5c0::/28fc7c:5cf:ffff:ffff:ffff:ffff:ffff:ffff
94fc7c:5d0::/28fc7c:5df:ffff:ffff:ffff:ffff:ffff:ffff
95fc7c:5e0::/28fc7c:5ef:ffff:ffff:ffff:ffff:ffff:ffff
96fc7c:5f0::/28fc7c:5ff:ffff:ffff:ffff:ffff:ffff:ffff
97fc7c:600::/28fc7c:60f:ffff:ffff:ffff:ffff:ffff:ffff
98fc7c:610::/28fc7c:61f:ffff:ffff:ffff:ffff:ffff:ffff
99fc7c:620::/28fc7c:62f:ffff:ffff:ffff:ffff:ffff:ffff
100fc7c:630::/28fc7c:63f:ffff:ffff:ffff:ffff:ffff:ffff
101fc7c:640::/28fc7c:64f:ffff:ffff:ffff:ffff:ffff:ffff
102fc7c:650::/28fc7c:65f:ffff:ffff:ffff:ffff:ffff:ffff
103fc7c:660::/28fc7c:66f:ffff:ffff:ffff:ffff:ffff:ffff
104fc7c:670::/28fc7c:67f:ffff:ffff:ffff:ffff:ffff:ffff
105fc7c:680::/28fc7c:68f:ffff:ffff:ffff:ffff:ffff:ffff
106fc7c:690::/28fc7c:69f:ffff:ffff:ffff:ffff:ffff:ffff
107fc7c:6a0::/28fc7c:6af:ffff:ffff:ffff:ffff:ffff:ffff
108fc7c:6b0::/28fc7c:6bf:ffff:ffff:ffff:ffff:ffff:ffff
109fc7c:6c0::/28fc7c:6cf:ffff:ffff:ffff:ffff:ffff:ffff
110fc7c:6d0::/28fc7c:6df:ffff:ffff:ffff:ffff:ffff:ffff
111fc7c:6e0::/28fc7c:6ef:ffff:ffff:ffff:ffff:ffff:ffff
112fc7c:6f0::/28fc7c:6ff:ffff:ffff:ffff:ffff:ffff:ffff
113fc7c:700::/28fc7c:70f:ffff:ffff:ffff:ffff:ffff:ffff
114fc7c:710::/28fc7c:71f:ffff:ffff:ffff:ffff:ffff:ffff
115fc7c:720::/28fc7c:72f:ffff:ffff:ffff:ffff:ffff:ffff
116fc7c:730::/28fc7c:73f:ffff:ffff:ffff:ffff:ffff:ffff
117fc7c:740::/28fc7c:74f:ffff:ffff:ffff:ffff:ffff:ffff
118fc7c:750::/28fc7c:75f:ffff:ffff:ffff:ffff:ffff:ffff
119fc7c:760::/28fc7c:76f:ffff:ffff:ffff:ffff:ffff:ffff
120fc7c:770::/28fc7c:77f:ffff:ffff:ffff:ffff:ffff:ffff
121fc7c:780::/28fc7c:78f:ffff:ffff:ffff:ffff:ffff:ffff
122fc7c:790::/28fc7c:79f:ffff:ffff:ffff:ffff:ffff:ffff
123fc7c:7a0::/28fc7c:7af:ffff:ffff:ffff:ffff:ffff:ffff
124fc7c:7b0::/28fc7c:7bf:ffff:ffff:ffff:ffff:ffff:ffff
125fc7c:7c0::/28fc7c:7cf:ffff:ffff:ffff:ffff:ffff:ffff
126fc7c:7d0::/28fc7c:7df:ffff:ffff:ffff:ffff:ffff:ffff
127fc7c:7e0::/28fc7c:7ef:ffff:ffff:ffff:ffff:ffff:ffff
128fc7c:7f0::/28fc7c:7ff:ffff:ffff:ffff:ffff:ffff:ffff
129fc7c:800::/28fc7c:80f:ffff:ffff:ffff:ffff:ffff:ffff
130fc7c:810::/28fc7c:81f:ffff:ffff:ffff:ffff:ffff:ffff
131fc7c:820::/28fc7c:82f:ffff:ffff:ffff:ffff:ffff:ffff
132fc7c:830::/28fc7c:83f:ffff:ffff:ffff:ffff:ffff:ffff
133fc7c:840::/28fc7c:84f:ffff:ffff:ffff:ffff:ffff:ffff
134fc7c:850::/28fc7c:85f:ffff:ffff:ffff:ffff:ffff:ffff
135fc7c:860::/28fc7c:86f:ffff:ffff:ffff:ffff:ffff:ffff
136fc7c:870::/28fc7c:87f:ffff:ffff:ffff:ffff:ffff:ffff
137fc7c:880::/28fc7c:88f:ffff:ffff:ffff:ffff:ffff:ffff
138fc7c:890::/28fc7c:89f:ffff:ffff:ffff:ffff:ffff:ffff
139fc7c:8a0::/28fc7c:8af:ffff:ffff:ffff:ffff:ffff:ffff
140fc7c:8b0::/28fc7c:8bf:ffff:ffff:ffff:ffff:ffff:ffff
141fc7c:8c0::/28fc7c:8cf:ffff:ffff:ffff:ffff:ffff:ffff
142fc7c:8d0::/28fc7c:8df:ffff:ffff:ffff:ffff:ffff:ffff
143fc7c:8e0::/28fc7c:8ef:ffff:ffff:ffff:ffff:ffff:ffff
144fc7c:8f0::/28fc7c:8ff:ffff:ffff:ffff:ffff:ffff:ffff
145fc7c:900::/28fc7c:90f:ffff:ffff:ffff:ffff:ffff:ffff
146fc7c:910::/28fc7c:91f:ffff:ffff:ffff:ffff:ffff:ffff
147fc7c:920::/28fc7c:92f:ffff:ffff:ffff:ffff:ffff:ffff
148fc7c:930::/28fc7c:93f:ffff:ffff:ffff:ffff:ffff:ffff
149fc7c:940::/28fc7c:94f:ffff:ffff:ffff:ffff:ffff:ffff
150fc7c:950::/28fc7c:95f:ffff:ffff:ffff:ffff:ffff:ffff
151fc7c:960::/28fc7c:96f:ffff:ffff:ffff:ffff:ffff:ffff
152fc7c:970::/28fc7c:97f:ffff:ffff:ffff:ffff:ffff:ffff
153fc7c:980::/28fc7c:98f:ffff:ffff:ffff:ffff:ffff:ffff
154fc7c:990::/28fc7c:99f:ffff:ffff:ffff:ffff:ffff:ffff
155fc7c:9a0::/28fc7c:9af:ffff:ffff:ffff:ffff:ffff:ffff
156fc7c:9b0::/28fc7c:9bf:ffff:ffff:ffff:ffff:ffff:ffff
157fc7c:9c0::/28fc7c:9cf:ffff:ffff:ffff:ffff:ffff:ffff
158fc7c:9d0::/28fc7c:9df:ffff:ffff:ffff:ffff:ffff:ffff
159fc7c:9e0::/28fc7c:9ef:ffff:ffff:ffff:ffff:ffff:ffff
160fc7c:9f0::/28fc7c:9ff:ffff:ffff:ffff:ffff:ffff:ffff
161fc7c:a00::/28fc7c:a0f:ffff:ffff:ffff:ffff:ffff:ffff
162fc7c:a10::/28fc7c:a1f:ffff:ffff:ffff:ffff:ffff:ffff
163fc7c:a20::/28fc7c:a2f:ffff:ffff:ffff:ffff:ffff:ffff
164fc7c:a30::/28fc7c:a3f:ffff:ffff:ffff:ffff:ffff:ffff
165fc7c:a40::/28fc7c:a4f:ffff:ffff:ffff:ffff:ffff:ffff
166fc7c:a50::/28fc7c:a5f:ffff:ffff:ffff:ffff:ffff:ffff
167fc7c:a60::/28fc7c:a6f:ffff:ffff:ffff:ffff:ffff:ffff
168fc7c:a70::/28fc7c:a7f:ffff:ffff:ffff:ffff:ffff:ffff
169fc7c:a80::/28fc7c:a8f:ffff:ffff:ffff:ffff:ffff:ffff
170fc7c:a90::/28fc7c:a9f:ffff:ffff:ffff:ffff:ffff:ffff
171fc7c:aa0::/28fc7c:aaf:ffff:ffff:ffff:ffff:ffff:ffff
172fc7c:ab0::/28fc7c:abf:ffff:ffff:ffff:ffff:ffff:ffff
173fc7c:ac0::/28fc7c:acf:ffff:ffff:ffff:ffff:ffff:ffff
174fc7c:ad0::/28fc7c:adf:ffff:ffff:ffff:ffff:ffff:ffff
175fc7c:ae0::/28fc7c:aef:ffff:ffff:ffff:ffff:ffff:ffff
176fc7c:af0::/28fc7c:aff:ffff:ffff:ffff:ffff:ffff:ffff
177fc7c:b00::/28fc7c:b0f:ffff:ffff:ffff:ffff:ffff:ffff
178fc7c:b10::/28fc7c:b1f:ffff:ffff:ffff:ffff:ffff:ffff
179fc7c:b20::/28fc7c:b2f:ffff:ffff:ffff:ffff:ffff:ffff
180fc7c:b30::/28fc7c:b3f:ffff:ffff:ffff:ffff:ffff:ffff
181fc7c:b40::/28fc7c:b4f:ffff:ffff:ffff:ffff:ffff:ffff
182fc7c:b50::/28fc7c:b5f:ffff:ffff:ffff:ffff:ffff:ffff
183fc7c:b60::/28fc7c:b6f:ffff:ffff:ffff:ffff:ffff:ffff
184fc7c:b70::/28fc7c:b7f:ffff:ffff:ffff:ffff:ffff:ffff
185fc7c:b80::/28fc7c:b8f:ffff:ffff:ffff:ffff:ffff:ffff
186fc7c:b90::/28fc7c:b9f:ffff:ffff:ffff:ffff:ffff:ffff
187fc7c:ba0::/28fc7c:baf:ffff:ffff:ffff:ffff:ffff:ffff
188fc7c:bb0::/28fc7c:bbf:ffff:ffff:ffff:ffff:ffff:ffff
189fc7c:bc0::/28fc7c:bcf:ffff:ffff:ffff:ffff:ffff:ffff
190fc7c:bd0::/28fc7c:bdf:ffff:ffff:ffff:ffff:ffff:ffff
191fc7c:be0::/28fc7c:bef:ffff:ffff:ffff:ffff:ffff:ffff
192fc7c:bf0::/28fc7c:bff:ffff:ffff:ffff:ffff:ffff:ffff
193fc7c:c00::/28fc7c:c0f:ffff:ffff:ffff:ffff:ffff:ffff
194fc7c:c10::/28fc7c:c1f:ffff:ffff:ffff:ffff:ffff:ffff
195fc7c:c20::/28fc7c:c2f:ffff:ffff:ffff:ffff:ffff:ffff
196fc7c:c30::/28fc7c:c3f:ffff:ffff:ffff:ffff:ffff:ffff
197fc7c:c40::/28fc7c:c4f:ffff:ffff:ffff:ffff:ffff:ffff
198fc7c:c50::/28fc7c:c5f:ffff:ffff:ffff:ffff:ffff:ffff
199fc7c:c60::/28fc7c:c6f:ffff:ffff:ffff:ffff:ffff:ffff
200fc7c:c70::/28fc7c:c7f:ffff:ffff:ffff:ffff:ffff:ffff
201fc7c:c80::/28fc7c:c8f:ffff:ffff:ffff:ffff:ffff:ffff
202fc7c:c90::/28fc7c:c9f:ffff:ffff:ffff:ffff:ffff:ffff
203fc7c:ca0::/28fc7c:caf:ffff:ffff:ffff:ffff:ffff:ffff
204fc7c:cb0::/28fc7c:cbf:ffff:ffff:ffff:ffff:ffff:ffff
205fc7c:cc0::/28fc7c:ccf:ffff:ffff:ffff:ffff:ffff:ffff
206fc7c:cd0::/28fc7c:cdf:ffff:ffff:ffff:ffff:ffff:ffff
207fc7c:ce0::/28fc7c:cef:ffff:ffff:ffff:ffff:ffff:ffff
208fc7c:cf0::/28fc7c:cff:ffff:ffff:ffff:ffff:ffff:ffff
209fc7c:d00::/28fc7c:d0f:ffff:ffff:ffff:ffff:ffff:ffff
210fc7c:d10::/28fc7c:d1f:ffff:ffff:ffff:ffff:ffff:ffff
211fc7c:d20::/28fc7c:d2f:ffff:ffff:ffff:ffff:ffff:ffff
212fc7c:d30::/28fc7c:d3f:ffff:ffff:ffff:ffff:ffff:ffff
213fc7c:d40::/28fc7c:d4f:ffff:ffff:ffff:ffff:ffff:ffff
214fc7c:d50::/28fc7c:d5f:ffff:ffff:ffff:ffff:ffff:ffff
215fc7c:d60::/28fc7c:d6f:ffff:ffff:ffff:ffff:ffff:ffff
216fc7c:d70::/28fc7c:d7f:ffff:ffff:ffff:ffff:ffff:ffff
217fc7c:d80::/28fc7c:d8f:ffff:ffff:ffff:ffff:ffff:ffff
218fc7c:d90::/28fc7c:d9f:ffff:ffff:ffff:ffff:ffff:ffff
219fc7c:da0::/28fc7c:daf:ffff:ffff:ffff:ffff:ffff:ffff
220fc7c:db0::/28fc7c:dbf:ffff:ffff:ffff:ffff:ffff:ffff
221fc7c:dc0::/28fc7c:dcf:ffff:ffff:ffff:ffff:ffff:ffff
222fc7c:dd0::/28fc7c:ddf:ffff:ffff:ffff:ffff:ffff:ffff
223fc7c:de0::/28fc7c:def:ffff:ffff:ffff:ffff:ffff:ffff
224fc7c:df0::/28fc7c:dff:ffff:ffff:ffff:ffff:ffff:ffff
225fc7c:e00::/28fc7c:e0f:ffff:ffff:ffff:ffff:ffff:ffff
226fc7c:e10::/28fc7c:e1f:ffff:ffff:ffff:ffff:ffff:ffff
227fc7c:e20::/28fc7c:e2f:ffff:ffff:ffff:ffff:ffff:ffff
228fc7c:e30::/28fc7c:e3f:ffff:ffff:ffff:ffff:ffff:ffff
229fc7c:e40::/28fc7c:e4f:ffff:ffff:ffff:ffff:ffff:ffff
230fc7c:e50::/28fc7c:e5f:ffff:ffff:ffff:ffff:ffff:ffff
231fc7c:e60::/28fc7c:e6f:ffff:ffff:ffff:ffff:ffff:ffff
232fc7c:e70::/28fc7c:e7f:ffff:ffff:ffff:ffff:ffff:ffff
233fc7c:e80::/28fc7c:e8f:ffff:ffff:ffff:ffff:ffff:ffff
234fc7c:e90::/28fc7c:e9f:ffff:ffff:ffff:ffff:ffff:ffff
235fc7c:ea0::/28fc7c:eaf:ffff:ffff:ffff:ffff:ffff:ffff
236fc7c:eb0::/28fc7c:ebf:ffff:ffff:ffff:ffff:ffff:ffff
237fc7c:ec0::/28fc7c:ecf:ffff:ffff:ffff:ffff:ffff:ffff
238fc7c:ed0::/28fc7c:edf:ffff:ffff:ffff:ffff:ffff:ffff
239fc7c:ee0::/28fc7c:eef:ffff:ffff:ffff:ffff:ffff:ffff
240fc7c:ef0::/28fc7c:eff:ffff:ffff:ffff:ffff:ffff:ffff
241fc7c:f00::/28fc7c:f0f:ffff:ffff:ffff:ffff:ffff:ffff
242fc7c:f10::/28fc7c:f1f:ffff:ffff:ffff:ffff:ffff:ffff
243fc7c:f20::/28fc7c:f2f:ffff:ffff:ffff:ffff:ffff:ffff
244fc7c:f30::/28fc7c:f3f:ffff:ffff:ffff:ffff:ffff:ffff
245fc7c:f40::/28fc7c:f4f:ffff:ffff:ffff:ffff:ffff:ffff
246fc7c:f50::/28fc7c:f5f:ffff:ffff:ffff:ffff:ffff:ffff
247fc7c:f60::/28fc7c:f6f:ffff:ffff:ffff:ffff:ffff:ffff
248fc7c:f70::/28fc7c:f7f:ffff:ffff:ffff:ffff:ffff:ffff
249fc7c:f80::/28fc7c:f8f:ffff:ffff:ffff:ffff:ffff:ffff
250fc7c:f90::/28fc7c:f9f:ffff:ffff:ffff:ffff:ffff:ffff
251fc7c:fa0::/28fc7c:faf:ffff:ffff:ffff:ffff:ffff:ffff
252fc7c:fb0::/28fc7c:fbf:ffff:ffff:ffff:ffff:ffff:ffff
253fc7c:fc0::/28fc7c:fcf:ffff:ffff:ffff:ffff:ffff:ffff
254fc7c:fd0::/28fc7c:fdf:ffff:ffff:ffff:ffff:ffff:ffff
255fc7c:fe0::/28fc7c:fef:ffff:ffff:ffff:ffff:ffff:ffff
256fc7c:ff0::/28fc7c: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.