What does /24 mean in CIDR?

A /24 prefix means the first 24 bits identify the network and the remaining 8 bits identify addresses inside that subnet. The equivalent subnet mask is 255.255.255.0.

What is the difference between network and broadcast address?

The network address identifies the subnet itself. The broadcast address is the highest address in a traditional IPv4 subnet and is used to reach all hosts on that subnet.

How many usable hosts are in a /24 subnet?

A traditional /24 has 256 total addresses and 254 usable host addresses after excluding the network and broadcast addresses.

Subnet Calculator — IPv4 CIDR, Mask & Host Range

Calculate an IPv4 subnet

Enter an IPv4 address. You can include the prefix directly, such as 192.168.1.10/24, or choose it separately.

IPv4 address and prefix

VALID IPv4 SUBNET—

Network address—

Broadcast address—

Subnet mask—

Wildcard mask—

First usable—

Last usable—

Total addresses—

Usable addresses—

Host bits—

Address position—

IP class—

Private range—

Binary view

IP—

Mask—

Network—

Split this network into smaller subnets

Choose a longer prefix. The tool will show the subnet count and a preview of the resulting networks.

New prefix

Preview is limited to the first 16 subnets for very large splits.

#	Network	First usable	Last usable	Broadcast

What is a subnet calculator?

A subnet calculator converts an IPv4 address and CIDR prefix into the key values used to plan and troubleshoot networks. It determines the network boundary, address range, broadcast address, mask, wildcard mask, and number of addresses in the subnet.

Understanding CIDR prefixes

CIDR prefixes range from /0 to /32. A /24 uses 24 network bits and leaves 8 host bits, which creates 256 total IPv4 addresses. A /30 leaves 2 host bits and creates 4 total addresses.

Special cases: /31 and /32

A /31 contains two addresses and is commonly used on point-to-point links under RFC 3021, where both addresses can be used as endpoints. A /32 identifies one exact IPv4 address rather than a multi-address subnet.

Subnet mask vs wildcard mask

The subnet mask has 1 bits for the network portion and 0 bits for the host portion. The wildcard mask is its inverse. Wildcard masks are commonly seen in routing, access-control, and network configuration syntax.

Subnet Calculator FAQ

What does /24 mean?

A /24 prefix means the first 24 bits identify the network. Its subnet mask is 255.255.255.0, leaving 8 bits for addresses inside that network.

How many usable addresses are in a /24?

A traditional /24 contains 256 total IPv4 addresses. After excluding the network and broadcast addresses, 254 are available for ordinary host assignment.

Why does /31 show two usable addresses?

/31 networks are commonly used for point-to-point links. RFC 3021 allows both addresses to be used as endpoints, so this calculator treats both as usable.

Does this calculator support IPv6?

This page is intentionally focused on IPv4 subnetting. IPv6 uses different addressing and subnet-planning conventions and is better handled with a dedicated IPv6 calculator.