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Networking Tools & Calculators

Deterministic IP address calculators compliant with RFC 791, RFC 4632, RFC 4291, and RFC 5952. Fast bitwise calculations for subnetting, broadcast addresses, and host bounds.

Networking tools here are deterministic bitwise calculators: given an IP and prefix, they derive network address, broadcast, usable host range, and wildcard mask exactly as the math dictates — no approximations. IPv4 subnetting follows RFC 4632 (CIDR); IPv6 notation is normalized per RFC 4291 and RFC 5952.

Networkingpopular

IPv4 Subnet Calculator

Bitwise IPv4 subnetting calculations with full network, broadcast, wildcard, and binary breakdowns.

All Networking

Networking

CIDR to Subnet Mask Calculator

Bidirectional converter between CIDR prefix notation (/24) and dotted-decimal subnet masks.

Networking

IP Range Calculator

Calculate span and total quantity of addresses between start and end IPv4 addresses.

Networking

IPv4 Address Converter

Transform IPv4 addresses into raw 32-bit decimal, binary octets, and hex notation.

Networking

IPv6 Validator & Notation Tool

Validate IPv6 syntax, expand collapsed colons, and inspect address scopes.

Which tool for which job

  • Subnet Calculator — the everyday tool: enter CIDR like 192.168.1.0/26 and get the full breakdown.
  • IP Range to CIDR — the reverse direction: you have a start and end address and need the minimal set of prefixes covering it (e.g. writing a firewall rule).
  • IPv4/IPv6 tools — when working across address families, including compressed IPv6 forms like ::1 and 2001:db8::/32.

Reading a result correctly

A /26 on 192.168.1.0 gives network 192.168.1.0, broadcast 192.168.1.63, and 62 usable hosts — the first and last addresses are reserved. Special cases matter: /31 is valid for point-to-point links per RFC 3021 (2 addresses, both usable), and /32 is a single-host route. If the calculator reports "0 usable hosts" for a /32, that reflects classic conventions — check what your equipment actually allows.

Common mistakes

  • Off-by-one subnets: /25 splits a /24 into exactly two networks (0–127 and 128–255), not one with a "half range".
  • Using the broadcast address as a host, or the network address as a gateway.
  • Mixing decimal thinking with binary reality — 255.255.255.240 is /28 (16 addresses, 14 hosts), not "a /28 plus a bit".