The /26 prefix: 64 addresses, a quarter of a /24
A /26 leaves 6 host bits: 64 addresses under the mask 255.255.255.192. The last octet divides into quarters, with network addresses at .0, .64, .128, and .192 — four /26s to a /24.
This is the workhorse size for small but real segments: a DMZ, a management network, a VoIP island, or a branch-office LAN. Sixty-two usable hosts is enough for a complete small site with a firewall in front.
| Prefix length | /26 |
| Subnet mask | 255.255.255.192 |
| Wildcard mask | 0.0.0.63 |
| Total addresses | 64 |
| Usable hosts | 62 |
Where /26s earn their keep
DMZs are the textbook case: you want a handful of public-facing boxes on their own segment behind tight firewall rules, and a /26 gives you 62 addresses of room without burning a whole /24. Management networks — switches, PDUs, iLO and iDRAC interfaces — are the other classic tenant, small and static by nature.
The quarter-octet mental model
Memorize four numbers — 0, 64, 128, 192 — and you can do /26 math in your head. An address like 10.0.5.70 falls in the .64 network: usable .65 through .126, broadcast .127. The same rhythm repeats in every /26 you will ever meet; only the starting point shifts.
CIDR Calculator
Run the math on 10.0.0.0/26 — or any other block
Frequently asked questions
How many IP addresses are in a /26?
64 in total (2^6), with 62 usable for hosts.
What is the subnet mask of a /26?
255.255.255.192. The top two bits of the last octet are network bits, so the octet splits into four blocks of 64.
How many /26s fit in a /24?
Four, starting at .0, .64, .128, and .192.
What is a /26 typically used for?
Small dedicated segments: DMZs, out-of-band management networks, branch LANs, and voice VLANs — anywhere you need a few dozen addresses and a clean security boundary.