IPv4 Subnet Calculator
Calculate IPv4 subnet details, CIDR ranges, subnet masks, wildcard masks, usable hosts, binary notation, and subnet splits directly in your browser.
Enter an IPv4 address with CIDR prefix such as 192.168.10.25/27, 10.0.0.0/24, or 172.16.5.128/26 to calculate network details.
Advanced Subnet Options
Split the input subnet into smaller subnets using a longer prefix.
Calculated Output
Subnet calculation output will appear here.
Calculating IPv4 Subnets for Network Planning
IPv4 subnetting is used to divide address space into smaller, manageable network ranges. It appears in firewall rules, route tables, VPN configurations, cloud VPCs, security groups, access control lists, DHCP scopes, and infrastructure documentation.
This advanced IPv4 Subnet Calculator takes an address with CIDR prefix and calculates the network address, broadcast address, usable host range, subnet mask, wildcard mask, binary notation, and optional subnet splits. It is designed for practical DevOps, networking, and security troubleshooting tasks.
Using the Advanced Subnet Calculator
- Enter an IPv4 address with CIDR prefix, such as 192.168.10.25/27.
- Choose whether you want summary, table text, or JSON output.
- Enable binary notation when you want to inspect subnet math.
- Enable subnet splits to divide the range into smaller CIDR blocks.
- Click Calculate Subnet and copy the generated output.
Common IPv4 Subnet Calculator Use Cases
- Calculating network and broadcast addresses from CIDR notation.
- Finding first and last usable host addresses.
- Converting prefix length into subnet mask and wildcard mask.
- Splitting a larger network into smaller subnets.
- Planning cloud VPC, firewall, VPN, or ACL network ranges.
- Documenting internal networks for operations and security teams.
Example IPv4 Subnet Calculation
Input: 192.168.10.25/27 Calculated subnet: CIDR: 192.168.10.0/27 Network: 192.168.10.0 Broadcast: 192.168.10.31 Subnet mask: 255.255.255.224 Wildcard mask: 0.0.0.31 First usable: 192.168.10.1 Last usable: 192.168.10.30 Total addresses: 32 Usable hosts: 30
Understanding Prefix Length and Subnet Masks
CIDR prefix length tells you how many bits belong to the network portion of an IPv4 address. A /24 prefix means 24 network bits and 8 host bits. The equivalent subnet mask is 255.255.255.0.
Smaller prefix numbers create larger networks. Larger prefix numbers create smaller networks. For example, /24 contains 256 total addresses, while /27 contains 32 total addresses.
Frequently Asked Questions
What is an IPv4 subnet calculator?
An IPv4 subnet calculator takes an IP address and CIDR prefix and calculates network details such as subnet mask, network address, broadcast address, usable host range, and address counts.
What does CIDR prefix length mean?
CIDR prefix length is the number after the slash, such as /24 or /27. It defines how many bits are used for the network portion of the IPv4 address.
What are usable hosts?
In traditional IPv4 subnetting, usable hosts are addresses between the network address and broadcast address. /31 and /32 ranges are treated specially because they are often used for point-to-point or single-host scenarios.
Can this split a subnet into smaller subnets?
Yes. You can split a subnet by choosing a longer prefix or by entering a desired subnet count. The preview is capped to keep the browser responsive.
Does this support IPv6?
This tool focuses on IPv4 subnet calculation. IPv6 subnetting has different address sizes and needs a separate interface.
Are my IP addresses uploaded anywhere?
No. The calculation happens directly in your browser, and your IP addresses are not uploaded to a server.