Subnet IPv4 & CIDR Mask Calculator
Calculate subnets, network/broadcast addresses, usable IP ranges, and host counts from CIDR IP configurations.
Simplify Network Architecture Planning
Designing subnets for local networks, server configurations, or cloud systems like AWS/GCP requires precise IP address calculations. Our subnet calculator makes it easy to split network address blocks.
Calculate IP Allocations
Input a base IP address and subnet mask (in CIDR notation), and the calculator will determine the network mask, broadcast address, usable range, and maximum host capacity.
Key Benefits & Features
CIDR Block breakdowns
Displays subnet calculations from /1 to /32 masks.
Usable Range Margins
Excludes network and broadcast address overheads automatically.
Binary Calculations
Shows how IP segments map to binary blocks for network training.
How to Use the Subnet IPv4 Calculator Step-by-Step
This utility runs entirely inside your browser using client-side JavaScript. We prioritize your security: none of your inputted text is logged or stored.
- 1
Enter your base IP address (e.g. 192.168.1.1).
- 2
Select the subnet mask prefix limit (e.g. /24).
- 3
Click "Calculate Subnet".
- 4
Review network bounds, broadcast details, and host capacities.
Practical Examples
IP: 10.0.0.1, Mask: /24
Frequently Asked Questions (FAQ)
What is CIDR notation?▼
CIDR (Classless Inter-Domain Routing) notation represents a subnet mask using a slash followed by the number of bits set to 1, such as /24 for 255.255.255.0.
Why are there two less usable hosts than total IPs?▼
The first address in a subnet is reserved as the network address, and the last is reserved as the broadcast address, neither of which can be assigned to a host.
Ready to boost your productivity?
Browse our full list of free security & cryptography and make your daily content, coding, or math tasks easier.