Subnet Calculator - CIDR
Calculate subnets from any IP and CIDR. Network, broadcast, host ranges and more.
Tool Interface
IP address & subnet
Results (tap a value to copy it)
How to use
- Enter any IPv4 address.
- Set the subnet size with the CIDR prefix (slider, number, or dotted mask — they stay in sync).
- Press Calculate to see the network, broadcast, usable range, host counts, wildcard mask, binary form and IP class.
- Tap any result value to copy it to the clipboard.
100% private — all math runs in your browser. Nothing is uploaded or stored.
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About This Tool
Complete Subnet Details for Any IPv4 Address
The Subnet Calculator breaks down any IPv4 address into its full subnet details. Enter an address, set the subnet size with the CIDR prefix slider, number input or dotted mask (all three stay in sync), and press Calculate. You get the network address, broadcast address, first and last usable hosts, usable and total host counts, subnet mask, wildcard mask, binary form and IP class.
Tap any result value to copy it to the clipboard. All math runs in your browser, so nothing is uploaded or stored. It is perfect for network admins, students studying for certifications and developers configuring infrastructure. The tool is free and needs no signup.
How to Use the Subnet Calculator
Three steps to full subnet details.
- Enter an IPv4 address: Type any address, for example 192.168.1.10.
- Set the subnet size: Use the CIDR prefix slider, type the prefix number, or enter a dotted mask. They stay in sync.
- Click Calculate: See every subnet value. Tap any value to copy it.
Understanding the Results
- Network and broadcast: The first and last addresses of the subnet, not assignable to hosts.
- Usable range: First to last host addresses you can actually assign.
- Host counts: Total addresses minus network and broadcast gives usable hosts.
- Wildcard mask: The inverse of the subnet mask, used in access lists.
- IP class: The traditional A, B or C classification of the address.
Key Features
- Three input styles: CIDR slider, prefix number or dotted mask.
- Complete breakdown: Network, broadcast, ranges, counts, masks, binary and class.
- Tap to copy: Every result value copies with one tap.
- 100 percent private: All math runs in your browser. Nothing is uploaded or stored.
- Free for everyone: No signup, no cost, unlimited calculations.
Frequently Asked Questions (FAQ)
Is the Subnet Calculator free? Yes. It is completely free with no signup.
What is CIDR notation? The slash plus number after an address, like /24, showing how many bits are the network portion.
How many hosts fit in a /24? 254 usable hosts, from a total of 256 addresses minus network and broadcast.
What is a wildcard mask? The inverse of the subnet mask, used in router access control lists.
Does it support IPv6? This calculator handles IPv4. IPv6 subnetting follows different conventions.
Is my input stored? No. All math runs in your browser and nothing is uploaded or stored.
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