Network Engineering Tools

Free, fast, and accurate tools for subnet calculation, IP planning, VLAN management, and network configuration generation. No account needed.

Quick Subnet Calculator

Try it out, or use the full Subnet Calculator for detailed results.

All Tools

Learning Hub

Interactive tutorials and courses to master subnetting, CIDR, and networking fundamentals.

Subnet Calculator

Calculate network address, broadcast, host range, and more from any IPv4/IPv6 CIDR.

IPv4 Subnet Calculator

Classful and classless IPv4 subnetting with full breakdown.

IPv6 Subnet Calculator

Expand, shorten, and analyze IPv6 addresses and prefixes.

Wildcard Mask Calculator

Convert CIDR to wildcard masks for ACL configurations.

Binary Converter

Convert IP addresses between binary, hex, and decimal formats.

IP Planner

Plan subnets based on device counts per segment with growth margin.

Supernet Calculator

Aggregate multiple CIDR blocks into the smallest supernet.

Overlap Detector

Check multiple CIDR ranges for IP address collisions.

VLAN Planner

Plan VLAN IDs with subnet assignments and descriptions.

Config Generator

Generate router/switch configs for Cisco, Juniper, Huawei, Arista, and more.

Cloud IP Planner

Design VPC subnets for AWS, Azure, and GCP across availability zones.

VPC Peering Check

Verify non-overlapping CIDRs before establishing VPC peering connections.

Subnetting Cheat Sheet

Quick reference tables for CIDR prefixes, subnet masks, and host counts.

Subnetting Quiz

Test your subnetting skills with interactive practice questions.

Transit Gateway Planner

Design AWS Transit Gateway topologies with route tables and overlap detection.

Bandwidth Calculator

Calculate throughput, transfer times, and compare link types.

DNS Lookup

Look up A, AAAA, MX, NS, CNAME, TXT, and other DNS records.

MAC Address Lookup

Look up OUI vendor, identify MAC type, and convert to EUI-64.

BGP Prefix Filter Builder

Generate Cisco and Juniper prefix-list and route-map configurations.

Subnet Randomizer

Generate random subnetting questions to practice your skills.

SSL/TLS Checker

Inspect SSL/TLS certificate details, expiry dates, and SANs for any domain.

Port Scanner

Check which TCP ports are open on any host with service identification.

Subnet Splitter

Split any CIDR block into equal-sized subnets for network planning.

Why NetworkTools?

NetworkTools is a comprehensive suite of free online tools designed for network engineers, system administrators, and IT students. Whether you are calculating subnets for a new deployment, planning IP allocations across multiple segments, designing VLANs for your campus network, or preparing for certification exams like CCNA or JNCIA, NetworkTools provides accurate results instantly.

Unlike traditional IP address management (IPAM) solutions that require installation, configuration, and ongoing maintenance, NetworkTools runs entirely in your browser. Every tool is a standalone page with its own URL, making it easy to bookmark, share, and reference later. There is no login required, no software to install, and no data leaves your browser for core calculations.

Our tools support the full spectrum of network engineering tasks: from basic binary conversion and wildcard mask calculation to advanced multi-region cloud IP planning and vendor-specific configuration generation. We support Cisco IOS, Juniper JunOS, Huawei VRP, Arista EOS, MikroTik RouterOS, and Fortinet FortiOS — with Terraform export for infrastructure-as-code workflows.