IPv6 prefix range, address count as a power of two, and /64 subnets per prefix
Runs in your browser. Nothing you type is sent anywhere. Updated on 25 Oct 2026.IPv6 prefixes are too large to count host by host, so this page gives the size as a power of two: a /48 holds 2^80 addresses and 65,536 subnets of /64, the size one LAN normally gets. Enter an address with its prefix to see the network and which kind of range it is.
Open the page with 2001:db8:abcd::/48 already calculated.
Type your IPv6 address with its prefix length.
Read the first and last address, the expanded network and the address count as a power of two.
Check the badge for the kind of range, with the RFC that defines it, then press Copy.
The first and last address are shown in canonical RFC 5952 form, the network also fully expanded.
This subnet calculator takes an IPv4 or IPv6 address with a prefix and shows everything that follows from it. For IPv4 you get the network address, broadcast address, first and last usable host, the number of hosts, the subnet mask, the wildcard mask used by Cisco access lists and OSPF, the address as hex and as a 32-bit integer, and a binary view where the network bits and host bits are split so you can see exactly where the boundary falls.
You can type the prefix as /26 or give a dotted mask such as 255.255.255.192 after the address. A bare address is read as a /32. The split panel divides the network into equal smaller subnets, for example a /24 into four /26 blocks, and lists each block's range. A host-count box suggests the smallest prefix that still fits that many machines.
For IPv6 the calculator shows the network, the first and last address in the canonical RFC 5952 form, the network also fully expanded, the size as a power of two, and how many /64 subnets fit inside.
The rest of the article, and all 6 questions about Subnet Calculator, are on the Subnet Calculator page.
A /24 has 256 addresses. The first is the network address and the last is the broadcast address, so 254 remain for hosts. The general rule is 2 to the power of (32 minus the prefix), minus 2, which gives 62 for a /26 and 14 for a /28.
Yes. Type the address, a space, then the dotted mask, such as 192.168.1.130 255.255.255.128, and the calculator converts it to /25. A mask whose 1 bits are not all at the front, such as 255.0.255.0, is rejected with a message, because no prefix length matches it.
Pick a longer prefix in the split panel. A /24 split into /26 gives four blocks of 64 addresses: .0, .64, .128 and .192, each with 62 hosts. Up to 256 blocks are listed with their ranges; the total count is always shown, even when the list is cut short.
IPv6 prefixes are huge: a /64 alone holds 2^64 addresses, about 18 quintillion. A power of two is easier to compare than a 20-digit number, so the page shows 2^(128 minus the prefix), the exact figure beneath it, and how many /64 networks the prefix contains.
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