Free Online Network Calculator - CIDR, VLAN & Routing
Comprehensive network calculator for CIDR subnets, subnet splitting, VLAN 802.1Q tags, and route summarization. Free IPv4 networking tool for engineers.
What is a Network Calculator?
A network calculator is an essential tool for network engineers and administrators to quickly compute IPv4 subnetting details, split networks into smaller subnets, analyze VLAN 802.1Q tagging, and summarize multiple routes into a supernet. Instead of manually applying bitwise arithmetic, this tool instantly produces network address, broadcast address, host ranges, subnet masks, and binary representations.
How to Use the Network Calculator
- CIDR Calculator: Enter an IP address with CIDR prefix (e.g. 192.168.1.0/24) to get full subnet details.
- Subnet Splitter: Enter a network and choose how many equal subnets to divide it into — a table lists every resulting subnet.
- VLAN Calculator: Enter a VLAN ID (1–4094) to view its 802.1Q tag fields in decimal and binary.
- Route Summarization: Paste multiple CIDR routes (one per line) and get the smallest supernet that covers them all.
Network Calculator Features
- Full CIDR subnet breakdown — network, broadcast, host range, mask, wildcard
- Binary view of IP, mask, and network address for learning and verification
- Subnet splitter supports up to 64 equal sub-networks at a glance
- VLAN 802.1Q tag field breakdown with PCP, DEI, and VID in binary
- Route summarization finds the tightest supernet for a list of CIDRs
Network Calculator FAQ
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation expresses an IP address combined with its subnet prefix length, e.g. 192.168.1.0/24. The number after the slash indicates how many bits are used for the network portion.
How does subnet splitting work?
Splitting a /24 into 4 equal subnets produces four /26 networks. Each split doubles the prefix length by one bit, halving the address space. This tool calculates all resulting networks automatically.
What is route summarization?
Route summarization (supernetting) aggregates multiple contiguous subnets into a single, shorter-prefix route. This reduces routing table size and simplifies network management.
What is a VLAN 802.1Q tag?
IEEE 802.1Q adds a 4-byte tag to Ethernet frames to carry VLAN information. The tag contains a 12-bit VLAN ID (VID), a 3-bit Priority Code Point (PCP), and a 1-bit Drop Eligible Indicator (DEI).