Subnet Calculator
Calculate IPv4 subnet details from an address and subnet mask or prefix with network address, broadcast address, usable host range, wildcard mask, and binary views. Perfect for network planning, router configuration, and infrastructure debugging.
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What is Subnet Calculator?
The Subnet Calculator takes an IPv4 address and subnet mask or CIDR prefix length and computes all subnet details. It derives the network address, broadcast address, usable host range, wildcard mask, total host count, and usable host count. The tool also displays binary representations for educational purposes. All processing happens in the browser.
How does Subnet Calculator work?
This tool performs bitwise AND operations between the IP address and subnet mask to derive the network address, then calculates the broadcast address, host range, and address counts. It supports both dotted-decimal mask notation and CIDR prefix notation.
Key Features
- Calculates network and broadcast addresses
- Shows usable host IP range
- Displays wildcard mask
- Supports CIDR and dotted-decimal notation
- Shows binary representations
- Calculates total and usable host counts
- Real-time calculation
- Runs in the browser with no uploads
Common Use Cases
Planning network segmentation
Calculate subnet ranges when dividing a network into smaller subnets.
Configuring routers and firewalls
Determine network and broadcast addresses for access control rules.
Troubleshooting connectivity
Verify whether two IP addresses belong to the same subnet.
Learning networking concepts
Understand subnetting with binary representations and detailed breakdowns.
How to Use This Tool
Enter an IP address
Type an IPv4 address such as 192.168.1.100.
Enter the subnet mask or prefix
Type a mask like 255.255.255.0 or a CIDR prefix like /24.
View results
The tool displays network address, broadcast, host range, and counts.
Pro Tips
- 1
A /24 subnet has 256 total addresses and 254 usable hosts.
- 2
The first address in a subnet is the network address. The last is the broadcast.
- 3
Usable host addresses exclude the network and broadcast addresses.
- 4
CIDR notation (/prefix) is more compact than writing the full dotted-decimal mask.
Frequently Asked Questions
What CIDR prefixes are supported?
The tool supports all valid IPv4 CIDR prefixes from /0 to /32.
Is my content sent to a server?
No. All calculations happen in your browser. Nothing is transmitted.
What is the wildcard mask?
The wildcard mask is the inverse of the subnet mask. It is used in some routing and ACL configurations.
Can I enter private IP ranges?
Yes. The tool works with any valid IPv4 address including private ranges (10.x, 172.16-31.x, 192.168.x).
Does it support IPv6?
No. This tool only supports IPv4 addresses and subnet masks.