Network Tools
Fast, reliable networking utilities for planning, calculation, and troubleshooting
What's in this category
Network engineers spend a lot of their day translating between formats — subnet masks to CIDR, dotted-decimal to binary, prefix length to host count. These tools handle the math so you can focus on the design decision instead. Everything runs in your browser: no installation, no account, and your IP plans never leave the page you're working on.
Use the Subnet Calculator when you have an IP and a prefix and want the network, broadcast, and usable range. Use the Subnet Planner when you're designing a new network and need to carve a parent block into right-sized child subnets without overlap. The CIDR Converter translates between notation styles, especially when bouncing between Cisco wildcard masks and dotted netmasks. The MTU Calculator handles VPN, PPPoE, and tunneling work where Path MTU Discovery gets in the way. IPv6 variants are available for both subnet calculation and subnet planning.
Subnet Calculator
Calculate IPv4 network addresses, broadcast addresses, host ranges, and subnet details from IP/CIDR notation. Includes binary representation and subnet list visualization.
Open CalculatorIPv6 Subnet Calculator
Calculate IPv6 network addresses, prefix information, and address ranges. Full support for IPv6 CIDR notation and address compression.
Open CalculatorSubnet Planner
Plan and visualize subnetting schemes for IPv4 networks. Design hierarchical subnets, calculate required subnet sizes, and generate subnet lists with detailed information.
Open PlannerIPv6 Subnet Planner
Plan and visualize IPv6 subnet allocations with support for massive address spaces. Design hierarchical /64 subnets, assign VLANs, and export plans to CSV or JSON.
Open PlannerCIDR Notation Converter
Convert CIDR notation to IP ranges, detect overlaps between multiple networks, and convert IP ranges back to CIDR notation. Supports standard CIDR, subnet mask, and Cisco wildcard formats. Essential for firewall rules and ACL planning.
Open ConverterBit Calculator
Convert between bits, bytes, and larger units (KB, MB, GB, TB, etc.) with support for both legacy and IEEE notation. Perfect for network bandwidth and storage calculations.
Open CalculatorData Transfer Calculator
Calculate how long it takes to transfer data based on file size and transfer rate. Supports various units and displays results in seconds, minutes, hours, days, and weeks.
Open CalculatorJinja Template Builder
Build and test Jinja2 templates with syntax highlighting. Pre-built templates for network configs, Ansible playbooks, Docker Compose, and system configurations with live preview.
Open BuilderMTU Calculator
Calculate Maximum Transmission Unit (MTU) and Maximum Segment Size (MSS) with protocol overhead analysis. Includes VPN encryption overhead, PPPoE, VLAN tagging, and generates OS-specific Path MTU Discovery commands.
Open CalculatorIP Address Converter
Convert IPv4 addresses between dotted-decimal, binary, hexadecimal, and 32-bit integer representations. Two-way binding — edit any field and the rest update live. Essential for firewall rules, log parsing, and binary subnetting.
Open ConverterBuilt for network engineers
Every calculator here works offline once loaded, makes zero API calls, and stores nothing about your subnets or designs. The math is pure JavaScript — there's nothing to send to a server and no benefit to doing so. If we wanted to track you, we'd have to start now, and we're not going to.
Useful next: System Tools for credential generation, certificate parsing, and JWT decoding. Data Tools covers Base64, hashing, and JSON formatting — handy when working with payloads pulled out of packet captures.