Subnet Calculator

IP Address: ...
# of bits used in network portion of address
Subnet Mask:

Number of Usable Addresses: 254
Network Address:
Broadcast Address:
First Host Address:
Last Host Address:

This Subnet Calculator can help you calculate subnet masks and ranges of IP addresses. Enter your IP address and click on the "Calculate" button above.

The current address range is

The first usable host address is Most admins assign this to the router that connects their site to their ISP. They then configure their client machines to use this address as a default gateway.

For this network, the administrator should only configure machines with IP addresses in the range -

If you do not need to further subnet your IP address range, you should set the subnet mask on all of your computers to

The network address is Routing tables store the "route" to this network using the network address. Routing tables are used by software such as RIP and OSPF.

Without using a NAT server or proxy server, you can setup up to 254 machines with unique addresses (you will probably need to use one of these addresses as your router address, depending on your setup).

The broadcast address is If you send a message to this address, it will be broadcasted to all of the machines in that subnet.


Click here for the Windows 10 version of the Subnet Calculator

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Copyright (c) 2013 Thatcher Development Software, LLC. All rights reserved. No claim to original U.S. Gov't works.