Networking
IPv4 and IPv6 subnet arithmetic, computed in your browser.
- CIDR & Subnet CalculatorWork out the network address, usable host range, netmask and size of any IPv4 or IPv6 block.
- IP Converter & ValidatorConvert addresses to and from integers, validate a list, and cover an arbitrary range with CIDR blocks.
- DNS Record Builder & ParserBuild and read zone-file records, with checks for the trailing-dot and CNAME traps.
- HTTP Status & Header ReferenceLook up status codes with their real-world behaviour, and format or review response headers.
- Subnet SplitterDivide a network into equal subnets of a chosen prefix length.
- CIDR SummarizerCollapse a list of networks into the smallest equivalent set, merging adjacent blocks.
Runs locally
CIDR & Subnet Calculator
Work out the network address, usable host range, netmask and size of any IPv4 or IPv6 block.
Runs locally
IP Converter & Validator
Convert addresses to and from integers, validate a list, and cover an arbitrary range with CIDR blocks.
Runs locally
DNS Record Builder & Parser
Build and read zone-file records, with checks for the trailing-dot and CNAME traps.
Runs locally
HTTP Status & Header Reference
Look up status codes with their real-world behaviour, and format or review response headers.
Runs locally
Subnet Splitter
Divide a network into equal subnets of a chosen prefix length.
Runs locally
CIDR Summarizer
Collapse a list of networks into the smallest equivalent set, merging adjacent blocks.