Administrator utilities

IP / Subnet Calculator

Calculate subnet boundaries and address ranges for an IPv4 or IPv6 address.

Calculator All utilities

Subnet input

Enter an address and prefix

CIDR notation can also be pasted into the address field.

Calculated values

Subnet details

FamilyIPv4

Network—

Addresses—

FAQ

What does the CIDR prefix mean in 192.168.1.42/24?

The number after the slash tells you how many leading address bits belong to the network. For IPv4, /24 corresponds to mask 255.255.255.0, and 192.168.1.42 belongs to 192.168.1.0/24.

What does the calculator show for IPv4?

It calculates the network address, subnet mask, wildcard mask, broadcast address, first and last usable addresses, and address counts. Results appear after you press the calculate button.

Why is there no broadcast address for IPv6?

IPv6 does not use broadcast addresses. The calculator therefore shows the first and last addresses in the subnet without an IPv4-style broadcast field.

How are IPv4 /31 and /32 subnets counted?

For /31, the calculator treats both addresses as usable; this prefix is often used for point-to-point links. A /32 contains one address. In wider subnets, the network and broadcast addresses are normally excluded from usable host counts.

Is the entered IP address sent to a server?

No. Calculation runs locally in your browser when you press the button. The calculator does not check whether an address is assigned to a real host or whether the network is reachable.