IPv4 networking
IPv4 CIDR Range Calculator
Enter an IPv4 address followed by a CIDR prefix to calculate its complete subnet range.
Common prefixes
Calculated subnet
256 addresses192.168.1.0/24
Complete address range192.168.1.0192.168.1.255
- Host bits
- 8
- Total addresses
- 256
- Usable addresses
- 254
Traditional subnet: network and broadcast addresses are reserved.
Free Online IPv4 CIDR Subnet Range Calculator
Calculate the network address, broadcast address, usable host range, subnet mask, wildcard mask and total address count of any IPv4 block written in CIDR notation. Network engineers, cloud administrators and developers use these values to plan subnets, write firewall rules, size VPC ranges and document address allocations.
The calculator describes a block mathematically; it does not check whether the range is already in use, routed or permitted by your organization's addressing policy.
Instructions
How to calculate an IPv4 range
Type an IPv4 address followed by a slash and a prefix length in the input field, for example 192.168.1.10/24. Four octets from 0 to 255 and a prefix from /0 to /32 are accepted. The result is recalculated as you type, so there is no button to press: the network address, broadcast address, first and last usable host, subnet mask and wildcard mask appear immediately below the field.
Using the common prefixes
The "Common prefixes" row lets you switch the prefix length of the address you already typed with a single click. This is handy for comparing how much a block grows or shrinks: keeping the same address and moving from /26 to /24 shows the range expanding from 64 to 256 addresses without retyping anything.
Reading the results
The network address is the first address of the block and identifies the subnet itself. The broadcast address is the last address and reaches every host in the subnet. The usable range is what you can actually assign to interfaces. The subnet mask marks the network bits with ones, and the wildcard mask is its bitwise inverse, used by ACLs and routing protocols such as OSPF. Host bits tells you how many bits are left for addressing, and the total address count is two raised to that number.
Copying the result
Click "Copy result" to place the full calculation on your clipboard as text, ready to paste into documentation, a change request or a ticket. Everything is computed locally in your browser with plain bitwise arithmetic, so no address you type is ever sent anywhere.
How IPv4 CIDR ranges work
CIDR prefixes describe how many of the 32 IPv4 bits identify the network. A /24 leaves 8 host bits and contains 256 addresses. A /22 leaves 10 host bits and contains 1,024 addresses.
The network address is the first address in the calculated block and the broadcast address is the last. In traditional subnets from /0 through /30, those two addresses are reserved and the usable host range lies between them. /31 networks are commonly used for point-to-point links, while /32 identifies one individual host.