NETWORKING / ADDRESS PLANNING
Subnet Calculator
One IPv4 address and a prefix. A clearer view of the network around it.
YOUR NETWORK
- Network
- 192.168.50.0
- Subnet mask
- 255.255.255.0
- Wildcard mask
- 0.0.0.255
- Broadcast
- 192.168.50.255
- First host
- 192.168.50.1
- Last host
- 192.168.50.254
- Total addresses
- 256
- Usable endpoints
- 254
Conventional subnet arithmetic. Special-purpose address space and local allocation policies can further restrict assignment.
How the calculation works
An IPv4 address contains 32 bits. The prefix identifies how many belong to the network part; the remaining bits describe addresses within that block. The network address is the input address combined with the subnet mask using a bitwise AND.
For an ordinary subnet, the lowest address identifies the network and the highest is its directed broadcast address. Conventional host arithmetic subtracts those two from the total. It does not decide whether the address space is appropriate or available for your particular use.
A worked /24 example
For 192.168.50.10/24, the mask is 255.255.255.0, the network is 192.168.50.0, and the broadcast is 192.168.50.255. Conventional host addresses run from 192.168.50.1 to 192.168.50.254: 254 addresses.
Why /31 and /32 are different
Does a /31 have usable addresses?
For point-to-point links using RFC 3021 semantics, both addresses are endpoints and there is no subnet broadcast. This tool applies that interpretation; check that the devices and link design support it.
What does a /32 describe?
A /32 selects one IPv4 address. The result is shown as a host route with one endpoint, without a separate network/broadcast reservation.
Does this tell me which addresses are free?
No. Check DHCP leases, reservations, static allocations, and your address-management records. Mathematical membership in a subnet is different from an available address.
Put the result to work
Read Proxmox bridges and VLANs or plan a DHCP migration. Check the gateway, intended routing, and IPv6 separately before changing a live network.
Plan more than one network
Use the VLSM calculator to allocate several IPv4 networks by host count, IP Range to CIDR for an existing range, or the IPv6 subnet calculator for 128-bit prefixes.