Calculate IPv4 and IPv6 network ranges, subnet masks, usable addresses, network boundaries, and other CIDR information.
CIDR notation combines an IP address with a prefix length. For example,192.168.1.0/24represents a network where the first 24 bits identify the network portion.
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A CIDR Calculator helps you analyze IPv4 and IPv6 networks from a CIDR address such as 192.168.1.0/24 or 2001:db8::/32. It calculates network information including the prefix length, network address, address range, broadcast address where applicable, subnet mask, wildcard mask, and the number of available addresses.
CIDR stands for Classless Inter-Domain Routing. It is a notation and addressing method used to describe IP networks using an address followed by a prefix length, such as 10.0.0.0/16.
The prefix length indicates how many bits of the IP address belong to the network portion. The remaining bits represent addresses within that network.
CIDR replaced the older class-based network model and allows networks to be sized more precisely according to their requirements.
Enter an IPv4 or IPv6 address followed by a prefix length. For example, enter 192.168.1.0/24 for a typical private IPv4 subnet.
Click Calculate to analyze the network. You can also use the provided IPv4 and IPv6 examples to quickly test the calculator.
The result cards show the most important network values individually, and each value can be copied directly.
The prefix length determines the size of the network. In IPv4, /24 means that the first 24 bits are used for the network portion and the remaining 8 bits are available for addresses.
For example, a /24 IPv4 network contains 256 total addresses. In a traditional subnetting context, 254 of those addresses are normally considered usable host addresses because the network and broadcast addresses are reserved.
Larger prefixes such as /28 represent smaller IPv4 networks, while smaller prefixes such as /16 represent larger networks.
CIDR notation is widely used in cloud networking and infrastructure configuration. AWS VPCs, subnets, Kubernetes networking, VPN configurations, firewall rules, routing tables, and many other systems use CIDR ranges.
When designing infrastructure, selecting an appropriate CIDR range is important because overlapping networks can make routing, peering, VPN connectivity, and future expansion more difficult.
CIDR applies to both IPv4 and IPv6. IPv4 addresses contain 32 bits, while IPv6 addresses contain 128 bits.
IPv6 networks commonly use prefixes such as /32, /48, /56, /64, and others depending on the network design. Because IPv6 has a much larger address space, the meaning of a prefix length should always be considered relative to the 128-bit address size.
For IPv4, the network address identifies the subnet itself and the broadcast address identifies the broadcast destination for that subnet. Traditional host addressing normally excludes both from the usable host range.
The exact handling of special addresses can vary between systems and network technologies. The calculator provides the calculated range so you can use the values as a planning reference.
The CIDR calculation is performed locally in your browser. The IP addresses and CIDR ranges entered into the calculator are not sent to a ToolTunnel backend for processing.
This makes the calculator suitable for quickly checking private infrastructure ranges, internal network designs, Kubernetes CIDRs, and other network information without uploading the input.
A /24 prefix means that the first 24 bits of an IPv4 address identify the network. This leaves 8 bits for addresses, resulting in 256 total IPv4 addresses in the range.
An IPv4 /24 network contains 256 total addresses. In traditional subnetting, 254 are normally usable as host addresses because the network and broadcast addresses are reserved.
CIDR expresses the network boundary using a prefix length such as /24, while a subnet mask expresses the same boundary in dotted-decimal form, such as 255.255.255.0.
Yes. The calculator accepts IPv6 CIDR notation such as 2001:db8::/32 and calculates the corresponding network information supported by the underlying calculator.
A wildcard mask is the inverse of a subnet mask. It is commonly used in network access-control rules, routing configurations, and other systems where matching bits need to be represented.
No. CIDR calculations are performed locally in your browser. The entered IP address and CIDR range are not uploaded to or stored by ToolTunnel.