Network & Security · Local-first
Subnet / CIDR Calculator Online
Calculate network, broadcast and host ranges.
Open Subnet / CIDR CalculatorFree · No sign-up · Browser-based processing
What Subnet / CIDR Calculator does
Turn an IPv4 address and prefix into the network address, subnet mask, wildcard mask, broadcast address, usable host range and capacity.
Common uses
- Plan VLAN and routed network ranges
- Verify firewall and access-control entries
- Check usable hosts before assigning an address block
How to use Subnet / CIDR Calculator
- Enter an IPv4 address with a CIDR prefix, such as 192.168.10.34/24.
- Run the calculator to derive the network boundaries and masks.
- Copy the values into router, firewall, IPAM or documentation workflows.
Privacy: Runs locally in your browser. Input is not uploaded to the DevNet Kit server.
Subnet / CIDR Calculator example
Try the tool with this representative input:
192.168.10.34/24Subnet / CIDR Calculator FAQ
What does /24 mean?
The prefix reserves 24 bits for the network and leaves 8 host bits, producing 256 total IPv4 addresses.
How are /31 and /32 handled?
A /31 is treated as a two-address point-to-point range and a /32 as one host route.
Does the calculator contact a network service?
No. CIDR arithmetic runs entirely in the browser.