Does it support IPv6?

Yes. Both IPv4 and IPv6 CIDR notation are supported — a colon (:) in the input is automatically detected as IPv6.

Is the IP I enter sent to a server?

No. All calculations run inside your browser using BigInt arithmetic.

Are special prefixes like /31 and /32 supported?

Yes. Special ranges like /31 and /32, which have no or only one usable host, are calculated correctly.

Are /32 and /31 special?

Yes — /32 is a single host (firewall rules), /31 is point-to-point links with no broadcast.

What are the private ranges?

10.0.0.0/8 · 172.16.0.0/12 · 192.168.0.0/16 — internal ranges not routed on the internet.

📐 IPv4/IPv6 CIDR Calculator

Calculate the network range and usable IPs from CIDR notation.

CIDR input (e.g. 192.168.1.0/24 or 2001:db8::/32)

How to use

Enter CIDR notation (e.g. 192.168.1.0/24).
Network range info is calculated as you type.
Both IPv4 and IPv6 are supported.

🎯 Use Cases

Check usable IP range when designing subnets
Calculate ranges for firewall rules
Study for networking certifications (subnetting practice)

Example

Input

192.168.1.0/24

Output

Network address: 192.168.1.0
Broadcast address: 192.168.1.255
Subnet mask: 255.255.255.0
Wildcard mask: 0.0.0.255
Usable IPs: 192.168.1.1 – 192.168.1.254
Total addresses: 256

A /24 block holds 256 addresses; excluding the network and broadcast addresses, 192.168.1.1–192.168.1.254 (254 hosts) are assignable to devices.

Reading CIDR notation

CIDR packs a network's start address and prefix length (subnet) into one notation.

Item	Details
CIDR	`192.168.1.0/24` — address plus prefix bit count
Network address	First address of the range — not assigned to hosts
Broadcast	Last address — /31 and /32 handle this differently
Usable hosts	2^(32−prefix)−2 — /24 gives 254
Subnet mask	Dotted notation — /24 = 255.255.255.0

FAQ

Does it support IPv6?: Yes. Both IPv4 and IPv6 CIDR notation are supported — a colon (:) in the input is automatically detected as IPv6.
Is the IP I enter sent to a server?: No. All calculations run inside your browser using BigInt arithmetic.
Are special prefixes like /31 and /32 supported?: Yes. Special ranges like /31 and /32, which have no or only one usable host, are calculated correctly.
Are /32 and /31 special?: Yes — /32 is a single host (firewall rules), /31 is point-to-point links with no broadcast.
What are the private ranges?: 10.0.0.0/8 · 172.16.0.0/12 · 192.168.0.0/16 — internal ranges not routed on the internet.