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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/7
Addresses2^121
/64 networks2^57
Network
2a00::/7
First address
2a00::
Last address
2bff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
2,658,455,991,569,831,745,807,614,120,560,689,152 (2^121)
/64 networks (LANs)
144,115,188,075,855,872 (2^57)
Full form
2a00:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zones
a.2.ip6.arpa
b.2.ip6.arpa
/7 is not on a 4-bit boundary, so it takes 2 /8 zones.
Split into smaller subnets/16
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/16 (512)/20 (8,192)

2a00::/7 makes 512 subnets of /16; the first 256 are listed.

Subnets
#SubnetLast address
12a00::/162a00:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22a01::/162a01:ffff:ffff:ffff:ffff:ffff:ffff:ffff
32a02::/162a02:ffff:ffff:ffff:ffff:ffff:ffff:ffff
42a03::/162a03:ffff:ffff:ffff:ffff:ffff:ffff:ffff
52a04::/162a04:ffff:ffff:ffff:ffff:ffff:ffff:ffff
62a05::/162a05:ffff:ffff:ffff:ffff:ffff:ffff:ffff
72a06::/162a06:ffff:ffff:ffff:ffff:ffff:ffff:ffff
82a07::/162a07:ffff:ffff:ffff:ffff:ffff:ffff:ffff
92a08::/162a08:ffff:ffff:ffff:ffff:ffff:ffff:ffff
102a09::/162a09:ffff:ffff:ffff:ffff:ffff:ffff:ffff
112a0a::/162a0a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
122a0b::/162a0b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
132a0c::/162a0c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
142a0d::/162a0d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
152a0e::/162a0e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
162a0f::/162a0f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
172a10::/162a10:ffff:ffff:ffff:ffff:ffff:ffff:ffff
182a11::/162a11:ffff:ffff:ffff:ffff:ffff:ffff:ffff
192a12::/162a12:ffff:ffff:ffff:ffff:ffff:ffff:ffff
202a13::/162a13:ffff:ffff:ffff:ffff:ffff:ffff:ffff
212a14::/162a14:ffff:ffff:ffff:ffff:ffff:ffff:ffff
222a15::/162a15:ffff:ffff:ffff:ffff:ffff:ffff:ffff
232a16::/162a16:ffff:ffff:ffff:ffff:ffff:ffff:ffff
242a17::/162a17:ffff:ffff:ffff:ffff:ffff:ffff:ffff
252a18::/162a18:ffff:ffff:ffff:ffff:ffff:ffff:ffff
262a19::/162a19:ffff:ffff:ffff:ffff:ffff:ffff:ffff
272a1a::/162a1a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
282a1b::/162a1b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
292a1c::/162a1c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
302a1d::/162a1d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
312a1e::/162a1e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
322a1f::/162a1f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
332a20::/162a20:ffff:ffff:ffff:ffff:ffff:ffff:ffff
342a21::/162a21:ffff:ffff:ffff:ffff:ffff:ffff:ffff
352a22::/162a22:ffff:ffff:ffff:ffff:ffff:ffff:ffff
362a23::/162a23:ffff:ffff:ffff:ffff:ffff:ffff:ffff
372a24::/162a24:ffff:ffff:ffff:ffff:ffff:ffff:ffff
382a25::/162a25:ffff:ffff:ffff:ffff:ffff:ffff:ffff
392a26::/162a26:ffff:ffff:ffff:ffff:ffff:ffff:ffff
402a27::/162a27:ffff:ffff:ffff:ffff:ffff:ffff:ffff
412a28::/162a28:ffff:ffff:ffff:ffff:ffff:ffff:ffff
422a29::/162a29:ffff:ffff:ffff:ffff:ffff:ffff:ffff
432a2a::/162a2a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
442a2b::/162a2b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
452a2c::/162a2c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
462a2d::/162a2d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
472a2e::/162a2e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
482a2f::/162a2f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
492a30::/162a30:ffff:ffff:ffff:ffff:ffff:ffff:ffff
502a31::/162a31:ffff:ffff:ffff:ffff:ffff:ffff:ffff
512a32::/162a32:ffff:ffff:ffff:ffff:ffff:ffff:ffff
522a33::/162a33:ffff:ffff:ffff:ffff:ffff:ffff:ffff
532a34::/162a34:ffff:ffff:ffff:ffff:ffff:ffff:ffff
542a35::/162a35:ffff:ffff:ffff:ffff:ffff:ffff:ffff
552a36::/162a36:ffff:ffff:ffff:ffff:ffff:ffff:ffff
562a37::/162a37:ffff:ffff:ffff:ffff:ffff:ffff:ffff
572a38::/162a38:ffff:ffff:ffff:ffff:ffff:ffff:ffff
582a39::/162a39:ffff:ffff:ffff:ffff:ffff:ffff:ffff
592a3a::/162a3a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
602a3b::/162a3b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
612a3c::/162a3c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
622a3d::/162a3d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
632a3e::/162a3e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
642a3f::/162a3f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
652a40::/162a40:ffff:ffff:ffff:ffff:ffff:ffff:ffff
662a41::/162a41:ffff:ffff:ffff:ffff:ffff:ffff:ffff
672a42::/162a42:ffff:ffff:ffff:ffff:ffff:ffff:ffff
682a43::/162a43:ffff:ffff:ffff:ffff:ffff:ffff:ffff
692a44::/162a44:ffff:ffff:ffff:ffff:ffff:ffff:ffff
702a45::/162a45:ffff:ffff:ffff:ffff:ffff:ffff:ffff
712a46::/162a46:ffff:ffff:ffff:ffff:ffff:ffff:ffff
722a47::/162a47:ffff:ffff:ffff:ffff:ffff:ffff:ffff
732a48::/162a48:ffff:ffff:ffff:ffff:ffff:ffff:ffff
742a49::/162a49:ffff:ffff:ffff:ffff:ffff:ffff:ffff
752a4a::/162a4a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
762a4b::/162a4b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
772a4c::/162a4c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
782a4d::/162a4d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
792a4e::/162a4e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
802a4f::/162a4f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
812a50::/162a50:ffff:ffff:ffff:ffff:ffff:ffff:ffff
822a51::/162a51:ffff:ffff:ffff:ffff:ffff:ffff:ffff
832a52::/162a52:ffff:ffff:ffff:ffff:ffff:ffff:ffff
842a53::/162a53:ffff:ffff:ffff:ffff:ffff:ffff:ffff
852a54::/162a54:ffff:ffff:ffff:ffff:ffff:ffff:ffff
862a55::/162a55:ffff:ffff:ffff:ffff:ffff:ffff:ffff
872a56::/162a56:ffff:ffff:ffff:ffff:ffff:ffff:ffff
882a57::/162a57:ffff:ffff:ffff:ffff:ffff:ffff:ffff
892a58::/162a58:ffff:ffff:ffff:ffff:ffff:ffff:ffff
902a59::/162a59:ffff:ffff:ffff:ffff:ffff:ffff:ffff
912a5a::/162a5a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
922a5b::/162a5b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
932a5c::/162a5c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
942a5d::/162a5d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
952a5e::/162a5e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
962a5f::/162a5f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
972a60::/162a60:ffff:ffff:ffff:ffff:ffff:ffff:ffff
982a61::/162a61:ffff:ffff:ffff:ffff:ffff:ffff:ffff
992a62::/162a62:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1002a63::/162a63:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1012a64::/162a64:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1022a65::/162a65:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1032a66::/162a66:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1042a67::/162a67:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1052a68::/162a68:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1062a69::/162a69:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1072a6a::/162a6a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1082a6b::/162a6b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1092a6c::/162a6c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1102a6d::/162a6d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1112a6e::/162a6e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1122a6f::/162a6f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1132a70::/162a70:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1142a71::/162a71:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1152a72::/162a72:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1162a73::/162a73:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1172a74::/162a74:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1182a75::/162a75:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1192a76::/162a76:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1202a77::/162a77:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1212a78::/162a78:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1222a79::/162a79:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1232a7a::/162a7a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1242a7b::/162a7b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1252a7c::/162a7c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1262a7d::/162a7d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1272a7e::/162a7e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1282a7f::/162a7f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1292a80::/162a80:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1302a81::/162a81:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1312a82::/162a82:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1322a83::/162a83:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1332a84::/162a84:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1342a85::/162a85:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1352a86::/162a86:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1362a87::/162a87:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1372a88::/162a88:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1382a89::/162a89:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1392a8a::/162a8a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1402a8b::/162a8b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1412a8c::/162a8c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1422a8d::/162a8d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1432a8e::/162a8e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1442a8f::/162a8f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1452a90::/162a90:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1462a91::/162a91:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1472a92::/162a92:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1482a93::/162a93:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1492a94::/162a94:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1502a95::/162a95:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1512a96::/162a96:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1522a97::/162a97:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1532a98::/162a98:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1542a99::/162a99:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1552a9a::/162a9a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1562a9b::/162a9b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1572a9c::/162a9c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1582a9d::/162a9d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1592a9e::/162a9e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1602a9f::/162a9f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1612aa0::/162aa0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1622aa1::/162aa1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1632aa2::/162aa2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1642aa3::/162aa3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1652aa4::/162aa4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1662aa5::/162aa5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1672aa6::/162aa6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1682aa7::/162aa7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1692aa8::/162aa8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1702aa9::/162aa9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1712aaa::/162aaa:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1722aab::/162aab:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1732aac::/162aac:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1742aad::/162aad:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1752aae::/162aae:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1762aaf::/162aaf:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1772ab0::/162ab0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1782ab1::/162ab1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1792ab2::/162ab2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1802ab3::/162ab3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1812ab4::/162ab4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1822ab5::/162ab5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1832ab6::/162ab6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1842ab7::/162ab7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1852ab8::/162ab8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1862ab9::/162ab9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1872aba::/162aba:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1882abb::/162abb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1892abc::/162abc:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1902abd::/162abd:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1912abe::/162abe:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1922abf::/162abf:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1932ac0::/162ac0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1942ac1::/162ac1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1952ac2::/162ac2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1962ac3::/162ac3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1972ac4::/162ac4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1982ac5::/162ac5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1992ac6::/162ac6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2002ac7::/162ac7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2012ac8::/162ac8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2022ac9::/162ac9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2032aca::/162aca:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2042acb::/162acb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2052acc::/162acc:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2062acd::/162acd:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2072ace::/162ace:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2082acf::/162acf:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2092ad0::/162ad0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2102ad1::/162ad1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2112ad2::/162ad2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2122ad3::/162ad3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2132ad4::/162ad4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2142ad5::/162ad5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2152ad6::/162ad6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2162ad7::/162ad7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2172ad8::/162ad8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2182ad9::/162ad9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2192ada::/162ada:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2202adb::/162adb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2212adc::/162adc:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2222add::/162add:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2232ade::/162ade:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2242adf::/162adf:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2252ae0::/162ae0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2262ae1::/162ae1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2272ae2::/162ae2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2282ae3::/162ae3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2292ae4::/162ae4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2302ae5::/162ae5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2312ae6::/162ae6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2322ae7::/162ae7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2332ae8::/162ae8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2342ae9::/162ae9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2352aea::/162aea:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2362aeb::/162aeb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2372aec::/162aec:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2382aed::/162aed:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2392aee::/162aee:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2402aef::/162aef:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2412af0::/162af0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2422af1::/162af1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2432af2::/162af2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2442af3::/162af3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2452af4::/162af4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2462af5::/162af5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2472af6::/162af6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2482af7::/162af7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2492af8::/162af8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2502af9::/162af9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2512afa::/162afa:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2522afb::/162afb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2532afc::/162afc:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2542afd::/162afd:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2552afe::/162afe:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2562aff::/162aff:ffff: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.