CIDR Calculator

Use this IPv4 CIDR calculator to calculate subnet masks, network ranges, broadcast addresses, usable host counts, and CIDR-to-subnet-mask conversions.

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CIDR Input

Enter an IPv4 block like 192.168.1.0/24 to inspect subnet details, calculate CIDR ranges, and convert CIDR to a subnet mask.

CIDR block

Quick examples

Notes

This calculator is IPv4-only and normalizes the block to its network address.

For /31 the two addresses are treated as usable point-to-point peers. For /32 the single address is treated as the host.

Subnet Results

192.168.1.0/24

Subnet details calculated successfully

Normalized CIDR

192.168.1.0/24

Subnet Mask

255.255.255.0

Wildcard Mask

0.0.0.255

Network Address

192.168.1.0

Broadcast Address

192.168.1.255

First Usable Host

192.168.1.1

Last Usable Host

192.168.1.254

Total Addresses

256

Usable Hosts

254

Address Class

Class C

Scope

Private / loopback range

Mask Bits

11111111.11111111.11111111.00000000

Network Bits

11000000.10101000.00000001.00000000

How To Use

Paste a CIDR block to see the normalized subnet, its usable IPv4 range, and the exact mask values used for routing or firewall rules.

This is useful when checking whether an address belongs to a network, sizing a subnet, converting CIDR to subnet mask form, or confirming the host range for an allow-list.

CtrlshiftCcopy subnet summaryEscreset

Calculate IPv4 CIDR ranges and subnet details

Enter an IPv4 address with a CIDR prefix to calculate the subnet mask, network address, broadcast address, and usable host range. Use it to verify a network plan or quickly interpret a CIDR block in configuration.

How it works

Enter an IPv4 address and prefix length, such as /24.
The calculator derives the network boundaries from the prefix bits.
Copy the resulting mask, range, and host information into documentation or configuration review.

Capabilities and limits

Calculates IPv4 network and broadcast addresses.
Shows subnet masks and usable host counts for conventional host subnets.
Is an IPv4 calculator; IPv6 notation has different addressing rules.

Examples

Typical office subnet

192.168.10.42/24

Network: 192.168.10.0, broadcast: 192.168.10.255.

Small point-to-point range

10.0.0.9/30

A /30 has four addresses and is often used where two usable host addresses are required.

Frequently asked questions

What does /24 mean?

It means the first 24 bits identify the network. In IPv4, that corresponds to the mask 255.255.255.0.

Why are network and broadcast addresses excluded?

In traditional IPv4 subnets, those addresses identify the subnet and broadcast traffic rather than individual hosts.