IPv4 CIDR Subnet Calculator

This IPv4 CIDR subnet calculator converts CIDR notation into a network address, broadcast address, subnet mask, usable IP range, and host count. Enter an IPv4 address with a prefix, such as 192.168.1.10/24, or calculate multiple subnets in an ordered batch with structured JSON results for scripts and AI agents.

All calculations are deterministic and run inside the Actor without contacting external IP lookup services.

CIDR to IP range, subnet mask, and host count

Convert CIDR to an IP address range

For 192.168.1.10/24, the complete IP range is 192.168.1.0 through 192.168.1.255; the usable host range is 192.168.1.1 through 192.168.1.254. The canonical network CIDR is 192.168.1.0/24, even when the input contains a host address.

Find the subnet mask and usable host count

Use the subnet mask calculator to translate a prefix length into dotted-decimal notation and check subnet capacity:

CIDR prefix	Subnet mask	Total addresses	Usable hosts
/24	255.255.255.0	256	254
/27	255.255.255.224	32	30
/30	255.255.255.252	4	2

These are standard IPv4 host counts; cloud providers may reserve additional addresses.

Subnet planning for DevOps, firewalls, and IP address management

• Plan AWS VPC, Azure VNet, Google Cloud, Kubernetes, and on-premises subnets.
• Check whether a subnet has enough usable IP addresses for servers or devices.
• Convert CIDR notation into IP ranges for firewall rules and access control lists.
• Validate network and broadcast addresses during infrastructure automation.
• Add deterministic IPv4 calculations to DevOps workflows, scripts, and AI agents.
• Process multiple CIDR blocks for IP address management and network audits.

How to calculate an IPv4 subnet

1. Open the Actor in Apify Console.
2. Enter an IPv4 address followed by a CIDR prefix, such as 192.168.1.10/24.
3. Click Start.
4. Open the run's Dataset to view or download the calculated subnet data.

Provide one of these input fields:

The input form prefills 192.168.1.10/24; clear it when using cidrs for a batch. If both fields are omitted (including input {}), the Actor calculates this example subnet automatically.

Field	Type	Description
cidr	string	One IPv4 address with a /0–/32 prefix, such as 10.0.0.5/24
cidrs	string array	Multiple IPv4 CIDRs to calculate as an ordered batch

Single CIDR input

{
  "cidr": "192.168.1.10/24"
}

Batch IPv4 subnet calculations

Submit an array to calculate multiple IPv4 subnets in the same order:

{
  "cidrs": [
    "192.168.1.10/24",
    "10.0.0.1/30",
    "172.16.5.100/16"
  ]
}

IPv4 subnet calculator output

Each input CIDR produces one item in the default dataset:

{
  "input": "192.168.1.10/24",
  "networkAddress": "192.168.1.0",
  "broadcastAddress": "192.168.1.255",
  "subnetMask": "255.255.255.0",
  "firstUsableHost": "192.168.1.1",
  "lastUsableHost": "192.168.1.254",
  "totalAddresses": 256,
  "usableHostCount": 254,
  "canonicalNetworkCidr": "192.168.1.0/24"
}

Field	Description
input	Original IPv4 CIDR submitted to the Actor
networkAddress	First address in the subnet
broadcastAddress	Last address in the subnet
subnetMask	Dotted-decimal IPv4 subnet mask
firstUsableHost	First usable host address
lastUsableHost	Last usable host address
totalAddresses	Total number of addresses in the CIDR block
usableHostCount	Number of usable host addresses
canonicalNetworkCidr	Normalized network address and prefix
error	Validation error code and message for an invalid batch entry
index	Zero-based position of an invalid entry in a batch

IPv4 /31 and /32 subnet calculation examples

The Actor accepts IPv4 CIDR notation only; IPv6 is not supported. Prefixes /0 through /30 reserve the network and broadcast addresses, /31 treats both addresses as usable according to RFC 3021, and /32 represents one host address.

Input	Network	Broadcast	First usable	Last usable	Total	Usable
10.0.0.0/31	10.0.0.0	10.0.0.1	10.0.0.0	10.0.0.1	2	2
8.8.8.8/32	8.8.8.8	8.8.8.8	8.8.8.8	8.8.8.8	1	1

Invalid CIDR input and batch errors

IPv6 addresses, missing prefixes, and prefixes outside /0–/32 are unsupported. Apify validates inputs against the input schema before starting a run.

Invalid entries that reach the calculator produce structured error items. In a batch, valid entries are still calculated and retain their input order, but the Actor run finishes with a nonzero status if any entry is invalid.