IPv4 Subnet Calculator

Subnet Calculator

Enter any IP address and CIDR prefix to instantly calculate network address, broadcast, host range, subnet mask, wildcard mask and binary breakdown.

Input

IPv4 Address

Subnet Mask

CIDR Prefix Length

/0 /32 /24

Results

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Network address

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Broadcast address

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First usable host

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Last usable host

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Usable hosts

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Total addresses

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Subnet mask

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Wildcard mask

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IP class

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IP type

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Short notation

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Integer value

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Binary representation

Blue = network bits · Grey = host bits

Split network into subnets

New prefix length

Show first N subnets

Calculate a subnet above to see the split.

CIDR quick reference

CIDR	Subnet mask	Usable hosts	Total IPs	Wildcard

Networking reference

What is a subnet?

A subnet is a logical subdivision of an IP network. Subnetting splits a network into smaller segments to improve performance, security, and address management.

What is CIDR notation?

CIDR (Classless Inter-Domain Routing) uses a slash followed by a prefix length (e.g. /24) to define a network, replacing the old Class A/B/C system.

Private IP ranges (RFC 1918)

10.0.0.0/8 · 172.16.0.0/12 · 192.168.0.0/16. These ranges are reserved for private networks and are not routable on the public internet.

Wildcard mask

The inverse of the subnet mask. Used in ACLs and OSPF to specify which bits of an IP address should be ignored during matching.