🔢 CIDR Calculator - IPv4 Subnet & Network Tool

🌐 Network Input

Enter CIDR notation, IP with subnet mask, or single IP address

📋 Quick Examples
⚠️

Calculation Failed

🌐 Network Information

CIDR Notation:

{{ results.calculations.cidr_notation }}

Network Class:

{{ results.calculations.network_class }}

Network Address:

{{ results.calculations.network_address }}

Broadcast Address:

{{ results.calculations.broadcast_address }}

Subnet Mask:

{{ results.calculations.subnet_mask }}

Wildcard Mask:

{{ results.calculations.wildcard_mask }}

🏠 Host Information

First Host:

{{ results.calculations.first_host }}

Last Host:

{{ results.calculations.last_host }}

Total Addresses:

{{ results.calculations.total_addresses.toLocaleString() }}

Usable Hosts:

{{ results.calculations.usable_hosts.toLocaleString() }}

🔍 Network Properties

Network Type: {{ results.calculations.is_private ?'Private' :'Public' }}
Network Size: {{ results.calculations.summary.network_size }}
Subnet Type: {{ results.calculations.summary.subnet_type }}
Common Use:

{{ results.calculations.summary.common_use }}

⚠️ Loopback Network (127.0.0.0/8)
📡 Multicast Network (224.0.0.0/4)
🔗 Link-Local Network (169.254.0.0/16)

🔢 Binary Representation

Network Address:

{{ results.calculations.binary.network_address }}

Subnet Mask:

{{ results.calculations.binary.subnet_mask }}

Wildcard Mask:

{{ results.calculations.binary.wildcard_mask }}

🔗 Possible Subnets (Next Level)

{{ subnet.cidr }}
{{ subnet.network }} - {{ subnet.broadcast }} {{ subnet.hosts }} hosts

No network calculated yet

Enter a network address and click"Calculate Network" to analyze CIDR subnet information.

⚠️

ℹ️ About CIDR Calculator

CIDR notation for IPv4 subnet planning

CIDR, short for Classless Inter-Domain Routing, writes an IPv4 network as an address plus a prefix length such as 192.168.10.0/24. The prefix length says how many leading bits belong to the network; the remaining bits identify hosts inside that block. CIDR replaced classful A/B/C routing and address allocation, as described in RFC 4632, while the IPv4 address format itself is defined by RFC 791.

What this CIDR calculator returns

Network fields

  • Network address: the first address in the block, with host bits set to zero.
  • Broadcast address: the last address in traditional IPv4 subnets.
  • Subnet mask: the dotted-decimal form of the CIDR prefix length.
  • Wildcard mask: the inverse mask often used in ACL and routing configuration.

Host and range fields

  • First and last host: the usual assignable IPv4 range for the subnet.
  • Total addresses: the full block size, including reserved boundary addresses.
  • Usable hosts: addresses normally available for interfaces or virtual machines.
  • Network type: quick identification of private, public, loopback, or special-use space.

Common use cases

  • Plan VLANs, VPN ranges, cloud VPC subnets, and lab networks without overlapping address space.
  • Convert between CIDR notation and subnet masks for routers, firewalls, DHCP scopes, and access lists.
  • Check the network, broadcast, and usable host range before assigning static IPv4 addresses.
  • Document route summaries and IPAM records with consistent prefix lengths and address counts.

Worked example

For 192.168.10.0/26, the first 26 bits identify the network and 6 bits remain for host addresses.

  • Subnet mask: 255.255.255.192
  • Total addresses: 64
  • Usable host range: 192.168.10.1 through 192.168.10.62
  • Broadcast address: 192.168.10.63

Common IPv4 CIDR prefixes

/24

254 usual hosts

255.255.255.0

/26

62 usual hosts

255.255.255.192

/30

2 usual hosts

255.255.255.252

/32

single address

255.255.255.255

Limits and edge cases

  • This page calculates IPv4 CIDR blocks. IPv6 uses prefix notation too, but it does not use IPv4 broadcast addresses.
  • /31 point-to-point links are a special case: RFC 3021 allows both addresses on those links instead of reserving network and broadcast addresses.
  • /32 represents one host route or one exact IPv4 address, so there is no multi-host range to allocate.
  • Private ranges from RFC 1918 and special-purpose ranges from the IANA IPv4 Special-Purpose Address Registry may not be globally routable.
  • Large prefixes such as 10.0.0.0/8 contain millions of addresses; use summarized counts instead of expanding every host in operational documents.

Supported input formats

  • CIDR notation: 192.168.1.0/24 or 10.0.0.0/8
  • IP with subnet mask: 192.168.1.0 255.255.255.0
  • Single IPv4 address: 192.168.1.1, interpreted as a /32 host route

API Usage Example:

POST /api/tools/network/cidr-calculator
Content-Type: application/json

{
    "input": "192.168.1.0/24"
}
Ready