IP Subnet Splitter & Merger Tool

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IPv4 Subnet Splitter & Merger

Split any network into subnets • Merge subnets into supernets • Instant CIDR calculations

subnet splitter • subnet merger • CIDR calculator • IPv4 subnet tool • network calculator

✉️  Split a Network into Subnets

Enter a network in CIDR notation and choose the new prefix length to split into.

Network Address (CIDR) Format: x.x.x.x/prefix (e.g. 172.16.0.0/16)

New Prefix Length Must be larger than network prefix

💡 Quick Examples

Parent Network

Subnet Size

Total Subnets

Hosts per Subnet

📊  Subnet Results

#	Network / CIDR	Subnet Mask	First Host	Last Host	Broadcast	Hosts

🔗  Merge Subnets into Supernets

Enter multiple subnets (one per line) to find the smallest possible supernet(s) that cover them all.

Subnets to Merge (one per line, CIDR notation) 192.168.0.0/24 192.168.1.0/24 192.168.2.0/24 192.168.3.0/24 Supports IPv4 CIDR notation. Duplicate entries are removed automatically.

⚙️ Merge Options Summarize into fewest supernets Only merge contiguous subnets Load Example:

📊  Merge Results

✅ Input Subnets

⭐ Merged Supernet(s)

Supernet	Subnet Mask	Network	Broadcast	Total IPs	Covers Inputs

🏻  Subnet Calculator

Enter an IP address and prefix length (or subnet mask) to calculate all network details instantly.

IP Address or CIDR

Prefix

💡 Quick Examples:

🏻  Network Details

IP Address Network Address Broadcast Address First Usable Host Last Usable Host

CIDR Notation Subnet Mask Wildcard Mask Total IP Addresses Usable Host Count

💻  Binary Representation

IP Address

Subnet Mask

About This Subnet Tool

This free IPv4 Subnet Splitter & Merger allows network engineers, system administrators, and IT professionals to divide (split) large IP address blocks into smaller subnets and consolidate (merge) multiple smaller subnets into their covering supernets — all with instant CIDR calculations and no server-side processing.

✉️ Subnet Splitter Takes any CIDR block and divides it into equal-sized subnets of a specified prefix length. Shows network, broadcast, and host ranges for each.

🔗 Subnet Merger Aggregates multiple subnets into the fewest possible supernets. Useful for route summarization and simplifying routing tables in BGP and OSPF.

🏻 Subnet Calculator Full network details: network address, broadcast, first/last host, mask, wildcard, binary representation, IP class, and usable host count.

Frequently Asked Questions

What is CIDR notation? CIDR (Classless Inter-Domain Routing) notation expresses an IP address and its associated network prefix length. For example, 192.168.1.0/24 means the network has a 24-bit prefix, giving 256 total addresses (254 usable hosts). The /24 corresponds to a subnet mask of 255.255.255.0.

How does subnet splitting work? Splitting a network means increasing the prefix length. A /22 network split into /24 subnets produces 4 subnets (2^(24-22) = 4). Each subnet is one-quarter the size of the original, with its own network address, broadcast address, and host range. This is called subnetting.

What is route summarization (supernetting)? Route summarization combines multiple contiguous subnets into a single larger supernet route advertisement. Instead of advertising 4 × /24 routes, a router can advertise one /22 route. This reduces routing table size, speeds up routing decisions, and improves network stability. Our merger tool automates this calculation.

🔒 All calculations are performed entirely in your browser — no data is sent to any server. • IPv4 only • Supports CIDR /1 through /32