Last Host Calculator
Find the last usable host address in an IP subnet.
About Last Host Calculator
The last usable host address is the broadcast address minus one. The broadcast address (all host bits set to 1) is reserved for subnet-wide communication, so the address just before it is the last one assignable to a host device.
Formula
Last host
last_host = broadcast_address - 1
- broadcast_address
- Network address OR inverse mask
Worked example
With the default values below, Last Host Calculator returns Last Usable Host of 192.168.10.254. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Network Address
- 192.168.10.0
- Prefix Lengthaccepts 0–31
- 24
Results
- Last Usable Host
- 192.168.10.254
- Broadcast Address
- 192.168.10.255
- Prefix
- /24
Step by step
- 1Compute broadcast= 192.168.10.255
- 2Subtract 1 for last host= 192.168.10.254
Assumptions and limits
- The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
Why is the broadcast address not usable?
Packets sent to the broadcast address are delivered to every host on the subnet — assigning it to a specific device would break this fundamental networking mechanism and cause unpredictable behavior.
Is the last host commonly used for anything specific?
Some administrators assign the last usable host to the default gateway by convention (while others use the first). Either is valid — choose one convention and apply it consistently.