Tools / API
CIDR Calculator
IPv4/IPv6 subnets, scope, binary view, split, contains, range → CIDR. Free, runs entirely in your browser—nothing is uploaded.
What you can do
- IPv4/IPv6 subnets
- Scope
- Binary view
- Split
- Contains
- Range → CIDR
Private by design
CIDR Calculator runs entirely in your browser. Your input is never uploaded, there is no sign-up, and the tool keeps working offline after the first visit.
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- URL Inspector — Parse/build URLs, edit query, encode components.
- Base Converters — Text, hex, Base64/32/58, binary, data URI, hex dump, number bases.