CIDR Subnet Calculator
Perform quick IP subnet calculations, inspect network masks, usable ranges, and binaries. Split subnets visually — running 100% locally in your web browser.
Subnet Details
Binary Representation
Visual Subnet Splitter
Split your CIDR block into smaller subnets.
How to Use
- 1
Enter base IP
Type standard IPv4 network address in the IP field.
- 2
Choose CIDR size
Select target prefix size (e.g. /24) to calculate subnets.
- 3
Analyze range
Check the Usable Range, Network, Broadcast, and Host totals below.
- 4
Visual Splitter
Choose a target prefix size to dynamically split your subnet range visually.
Frequently Asked Questions
Is my subnet architecture secure on this tool?+
Yes. All calculations process in Javascript inside your web browser. No network API calls are made — your network configuration never leaves your machine.
What is CIDR?+
Classless Inter-Domain Routing (CIDR) is a method for allocating IP addresses and IP routing. It replaces the legacy class-based IP system with custom subnet sizes (represented by a slash and prefix number).
What does a /24 subnet mean?+
A /24 subnet mask allocates 24 bits for the network prefix and 8 bits for host addresses. This is represented as 255.255.255.0 and allows up to 254 usable host addresses.