IPv4 Subnet Calculator
Calculate IPv4 subnets from an address and CIDR or subnet mask with classification and mask conversion.
Subnet mask ↔ CIDR conversion
Mode
CIDR → Mask
Input
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Result
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What is IPv4 Subnet Calculator?
A subnet calculator converts between CIDR prefixes, masks, and usable host ranges so network engineers can plan addressing without spreadsheet errors.
How it works
Enter an IPv4 address and prefix length (or mask). PacketWizard computes network, broadcast, and host range details entirely in your browser.
Common issues
Off-by-one usable hosts
Remember network and broadcast addresses are reserved in typical IPv4 subnets (except special cases like /31 point-to-point).
Frequently asked questions
Should I use CIDR or dotted masks?
CIDR notation (like /24) is the modern default. The calculator accepts both so you can translate older documentation.
Related tools
Continue with these related PacketWizard tools for adjacent diagnostics.
CIDR CalculatorCalculate IPv4 network, broadcast, host ranges, masks, and binary representation from CIDR notation.IPv6 Subnet CalculatorExpand, compress, and analyze IPv6 subnets with prefix information and address classification.What Is My IPSee the public IPv4 or IPv6 address internet services observe for your current browser session.