# Subnet Calculator — IPv6, CIDR, Cloud, Language Guides, Conversions & Definitions
For the full tool, see: [https://capytoolkit.com/tools/network/subnet-calculator/](https://capytoolkit.com/tools/network/subnet-calculator/)
## Calculator Guides
[IPv6 Subnet Calculator Guide](https://capytoolkit.com/tools/network/subnet-calculator/ipv6-subnet-calculator/): Calculate IPv6 subnet boundaries, host ranges, and prefix sizes. Covers /64, /48, /128 sizing with dual-stack planning for AWS, Azure, and home networks.
[CIDR Subnet Calculator Guide](https://capytoolkit.com/tools/network/subnet-calculator/cidr-calculator/): Convert CIDR notation to subnet masks and host ranges. Covers /8 through /32, cloud CIDR blocks, and common network planning scenarios.
[Subnet Calculator vs MXToolbox](https://capytoolkit.com/tools/network/subnet-calculator/subnet-calculator-vs-mxtoolbox/): Compare CapyToolkit Subnet Calculator and MXToolbox subnet features. See which tool fits your workflow for IPv4, IPv6, and CIDR subnet planning.
## Cloud & Use-Case Guides
[Variable Length Subnet Masking (VLSM) Calculator](https://capytoolkit.com/tools/network/subnet-calculator/vlsm-subnet-calculator/): Use VLSM to allocate different-sized subnets from one address block. Covers host count planning, prefix selection, and VLSM calculation steps.
[Subnet Calculator for AWS VPC](https://capytoolkit.com/tools/network/subnet-calculator/aws-vpc-subnet-calculator/): Plan AWS VPC CIDR blocks and subnet sizes. Covers reserved IPs per subnet, multi-AZ layout, public/private tiers, and recommended prefix lengths for EC2 and EKS.
[Subnet Calculator for Azure VNet](https://capytoolkit.com/tools/network/subnet-calculator/azure-vnet-subnet-calculator/): Plan Azure Virtual Network CIDR blocks and subnet sizes. Covers Azure reserved IPs, hub-spoke topologies, and recommended prefix lengths for AKS and Application Gateway.
[Kubernetes Pod and Node Subnet Planning](https://capytoolkit.com/tools/network/subnet-calculator/kubernetes-subnet-planning/): Plan Kubernetes pod CIDR, service CIDR, and node subnet allocations. Covers CNI plugin IP requirements, pod density, and avoiding RFC 1918 conflicts.
[Network Segmentation and Subnet Isolation](https://capytoolkit.com/tools/network/subnet-calculator/network-segmentation-guide/): Plan network segments with CIDR subnets to isolate traffic, enforce security zones, and reduce blast radius. Covers VLAN layout, DMZ, IoT, and jump host patterns.
[Look Up Your Subnet Mask and CIDR Prefix Fast](https://capytoolkit.com/tools/network/subnet-calculator/subnetting-cheat-sheet/): Skip the binary math: look up any prefix from /8 through /32 for host counts, usable addresses, wildcard masks, and block sizes, then confirm the exact value with the calculator above.
[How to Convert CIDR Notation to a Subnet Mask](https://capytoolkit.com/tools/network/subnet-calculator/cidr-to-subnet-mask/): Step-by-step guide to converting CIDR prefix lengths to dotted-decimal subnet masks. Covers the binary method and common CIDR-to-mask equivalents for IPv4.
[How to Convert a Subnet Mask to CIDR Notation](https://capytoolkit.com/tools/network/subnet-calculator/subnet-mask-to-cidr/): Step-by-step guide to converting dotted-decimal subnet masks to CIDR prefix notation. Covers the bit-counting method and common mask-to-CIDR equivalents for IPv4.
## IPv4 / IPv6 Subnet & CIDR Calculator: Code Examples
[CIDR Notation Explained: Subnet Masks and Host Counts](https://capytoolkit.com/tools/network/subnet-calculator/code-examples/#cidr-notation-explained): Understand CIDR notation like /24, /16, and /32. Learn what each subnet mask means and how to calculate the number of usable hosts in a subnet.
[Subnet Calculations in Python with ipaddress Module](https://capytoolkit.com/tools/network/subnet-calculator/code-examples/#subnetting-in-python): Use Python's built-in ipaddress module to calculate subnets, list hosts, find network addresses, and do supernetting. No external packages required.
[Subnet Calculations in Bash with ipcalc and sipcalc](https://capytoolkit.com/tools/network/subnet-calculator/code-examples/#subnetting-in-bash): Perform subnet calculations in Bash using ipcalc, sipcalc, or manual bit manipulation. Works on Linux, macOS, and WSL.
[IPv6 Subnetting Basics: /64, /48, /128 Explained](https://capytoolkit.com/tools/network/subnet-calculator/code-examples/#ipv6-subnetting-basics): Learn IPv6 subnet sizing: why /64 is the standard, how /48 and /128 fit into addressing, and how to calculate IPv6 subnet boundaries and host counts.
[Subnet Calculations in JavaScript / Node.js](https://capytoolkit.com/tools/network/subnet-calculator/code-examples/#subnetting-in-javascript): Perform IPv4 subnet math in JavaScript using bitwise operators. Covers Node.js CIDR parsing with the ip-cidr and netmask packages, and browser-compatible BigInt for IPv6.
[Subnet Calculations in PowerShell](https://capytoolkit.com/tools/network/subnet-calculator/code-examples/#subnetting-in-powershell): Calculate IPv4 subnets in PowerShell using the .NET System.Net namespace or manual bitwise arithmetic. Covers network ranges, broadcast addresses, and CIDR parsing for automation scripts.
[Subnet Calculations in Go with net and netip Packages](https://capytoolkit.com/tools/network/subnet-calculator/code-examples/#subnetting-in-go): Perform IPv4 and IPv6 subnet math in Go using the standard library's net and netip packages. Covers CIDR parsing, address iteration, and subnet containment checks.
## IPv4 / IPv6 Subnet & CIDR Calculator: Conversions
[Hosts to CIDR — Subnet Calculator](https://capytoolkit.com/tools/network/subnet-calculator/conversions/#hosts-to-cidr): Calculating the right CIDR prefix for your host count adds 2 to account for the network and broadcast addresses, then finds the smallest power of 2 that covers the result. The prefix is 32 minus the number of host bits required.1
[CIDR to host count — Subnet Calculator](https://capytoolkit.com/tools/network/subnet-calculator/conversions/#cidr-to-host-count): Calculating the usable host count from a CIDR prefix raises 2 to the power of the host bits (32 minus the prefix length), then subtracts 2 for the network and broadcast addresses.1
## IPv4 / IPv6 Subnet & CIDR Calculator Reference
[What Is CIDR Notation?](https://capytoolkit.com/tools/network/subnet-calculator/reference/#what-is-cidr): CIDR (Classless Inter-Domain Routing) notation combines an IP address and prefix length into a compact representation like 192.168.0.0/24. Learn how it works and why it replaced classful addressing.
[What Is a Subnet Mask?](https://capytoolkit.com/tools/network/subnet-calculator/reference/#what-is-a-subnet-mask): A subnet mask identifies which bits of an IP address are the network portion and which are the host portion. Learn how subnet masks work, how they relate to CIDR notation, and how to read them.
[What Are Private IP Address Ranges?](https://capytoolkit.com/tools/network/subnet-calculator/reference/#private-ip-address-ranges): RFC 1918 defines three private IPv4 address ranges: 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. Learn which ranges to use and why they are not routable on the internet.
[What Is a Broadcast Address?](https://capytoolkit.com/tools/network/subnet-calculator/reference/#what-is-a-broadcast-address): A broadcast address is the last address in an IPv4 subnet, used to send packets to all devices on the network simultaneously. Learn how it is calculated and why IPv6 eliminated it.
[What Is Network Address Translation (NAT)?](https://capytoolkit.com/tools/network/subnet-calculator/reference/#what-is-nat): NAT allows multiple devices on a private network to share one public IP address. Learn how NAT works, the difference between SNAT and DNAT, and why IPv6 reduces reliance on NAT.
## Device Guides
[TP-Link Archer BE900 Subnet Settings Guide](https://capytoolkit.com/tools/network/subnet-calculator/tp-link-archer-be900-subnetting/): View and change subnet settings on the TP-Link Archer BE900 Wi-Fi 7 router. Default LAN IP, DHCP pool, and step-by-step admin UI guide for subnet customization.
[TP-Link Deco BE63 Subnet Settings Guide](https://capytoolkit.com/tools/network/subnet-calculator/tp-link-deco-be63-subnetting/): View and configure subnet settings on the TP-Link Deco BE63 mesh Wi-Fi 7 system. Default LAN, DHCP pool, and steps to change subnet mask or set up IoT isolation.
[Netgear Nighthawk RS700S Subnet Settings Guide](https://capytoolkit.com/tools/network/subnet-calculator/netgear-nighthawk-rs700s-subnetting/): Configure subnet settings on the Netgear Nighthawk RS700S Wi-Fi 7 router. Default LAN IP, DHCP pool, and steps to change the subnet mask in the admin UI.
[Ubiquiti UDM-Pro 10G Cloud Gateway Subnet Settings Guide](https://capytoolkit.com/tools/network/subnet-calculator/ubiquiti-unifi-dream-machine-pro-subnetting/): Configure subnets and VLANs on the Ubiquiti UDM-Pro 10G Cloud Gateway. Default LAN, multiple network configuration, VLAN-backed networks, and inter-VLAN routing in UniFi OS.
[Amazon eero Pro 7 Subnet Settings Guide](https://capytoolkit.com/tools/network/subnet-calculator/eero-pro-7-subnetting/): View and change subnet settings on the Amazon eero Pro 7 mesh router. Default LAN, DHCP configuration, and network isolation options via the eero app.
[ASUS ROG Rapture GT-BE98 Pro Subnet Settings Guide](https://capytoolkit.com/tools/network/subnet-calculator/asus-rog-rapture-gt-be98-subnetting/): Configure subnet and VLAN settings on the ASUS ROG Rapture GT-BE98 Pro gaming router. Default LAN IP, DHCP pool, and steps to use gaming QoS features with custom subnets.