Subnet Calculator
Calculate subnet ranges from an IP and CIDR prefix, an IP and subnet mask, or a required host count. This tool shows network boundaries, usable host range, subnet mask details, and related addressing information.
Subnet Results
What this tool does
Subnet Calculator helps you work out the boundaries of an IPv4 subnet from several starting points. You can enter an IP and CIDR prefix, an IP and dotted-decimal subnet mask, or an IP and required usable host count.
The tool returns the network address, broadcast address, usable host range, total address count, subnet mask, wildcard mask, and a few related networking details.
When this tool is useful
- Planning VLANs and small network segments
- Checking the valid host range for an existing subnet
- Converting subnet masks into CIDR notation
- Sizing a subnet based on required host count
- Working out reverse PTR zones for IPv4 ranges
Learn more
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How to Calculate a Subnet Range Step by Step
A practical guide to calculating network address, broadcast address, and usable host range from an IP address and subnet size.
What Is a Subnet Mask? Explained Clearly
Learn what a subnet mask does, how it separates network and host portions of an IPv4 address, and how it relates to CIDR and usable ranges.
CIDR Cheat Sheet for Common Subnet Sizes
Use this CIDR cheat sheet to quickly compare common subnet sizes, masks, block sizes, and usable host counts during subnet planning and troubleshooting.