Subnet Calculator
What network does 192.168.1.130/26 belong to, and which addresses can hosts actually use? Enter any IPv4 address and CIDR prefix to get the network, broadcast, usable range, masks, and the binary math behind them.
Network address
192.168.1.128
/26
Broadcast address
192.168.1.191
Usable hosts
62
2^(32−26) − 2
First usable
192.168.1.129
Last usable
192.168.1.190
Total addresses
64
Subnet mask
255.255.255.192
Wildcard mask
0.0.0.63
Address type
Private (RFC 1918 — 192.168.0.0/16)
192.168.1.130 in binary — network bits │ host bits
11000000.10101000.00000001.10 │ 000010
The network address is the IP bitwise-ANDed with the mask; the broadcast address sets all host bits to 1. Subnets of /30 and larger lose those two addresses, which is why a /26 offers 62 hosts, not 64. Wildcard masks (the mask inverted) appear in Cisco ACLs and OSPF configs.
How Subnetting Math Works
A /26 prefix means the first 26 bits identify the network and the last 6 identify the host. Bitwise-AND the address with the mask 255.255.255.192 and 192.168.1.130 lands in network 192.168.1.128; set the 6 host bits to 1 and you get the broadcast address 192.168.1.191. That leaves 2⁶ − 2 = 62 usable hosts, .129 through .190 — the −2 removes the network and broadcast addresses. The same arithmetic scales: 10.10.20.5/8 sits in network 10.0.0.0 with broadcast 10.255.255.255 and 16,777,214 usable hosts.
Worked example: 192.168.1.130/26
Mask 255.255.255.192 Wildcard 0.0.0.63 Network 192.168.1.128 Broadcast 192.168.1.191 Usable 192.168.1.129 – 192.168.1.190 (62 hosts) Usable hosts = 2^(32−prefix) − 2 /24 = 254 /26 = 62 /30 = 2 /31 = 2 (RFC 3021, point-to-point) /32 = 1 (host route) Private (RFC 1918): 10/8, 172.16/12, 192.168/16
Frequently Asked Questions
How many usable hosts are in a /24?
A /24 has 2^(32−24) = 256 total addresses, minus the network address and the broadcast address, leaving 254 usable hosts. The same formula gives a /26 62 hosts, a /27 30, and a /30 just 2 — which is why /30s (and now /31s) are used for router-to-router links.
How do I find the network address from an IP and subnet mask?
Bitwise-AND the address with the mask. For 192.168.1.130/26 the mask is 255.255.255.192; the last octet 130 (10000010) AND 192 (11000000) = 128, so the network is 192.168.1.128 and the broadcast is 192.168.1.191. Hosts can use .129 through .190.
Why do /31 and /32 subnets break the usable-host formula?
The −2 in 2^(32−p) − 2 removes the network and broadcast addresses, but RFC 3021 lets point-to-point /31 links use both of their addresses — 2 usable hosts with no broadcast at all. A /32 is a host route: one address identifying a single interface, common for loopbacks on routers.
Which IPv4 ranges are private?
RFC 1918 reserves 10.0.0.0/8 (16.7M addresses), 172.16.0.0/12, and 192.168.0.0/16 for private networks — they're not routable on the public internet, which is why every home router can use 192.168.1.0/24. Also special: 127.0.0.0/8 (loopback) and 169.254.0.0/16 (link-local, what you get when DHCP fails).