Subnet & CIDR IP Calculator
IPv4 NetworkingCalculate network addresses, broadcast addresses, usable host ranges, and wildcard masks from any IPv4 CIDR prefix.
Private by architecture:
All processing is 100% client-side memory. Your data never leaves this browser tab.
IPv4 Subnet Configuration
Presets:
| Network Address: | 192.168.1.0 |
|---|---|
| Broadcast Address: | 192.168.1.255 |
| Usable Host IP Range: | 192.168.1.1 to 192.168.1.254 |
| Total / Usable Hosts: | 256 total · 254 usable |
| Subnet Mask: | 255.255.255.0 |
| Wildcard Mask: | 0.0.0.255 |
| IP Class: | Class C |
| Binary Subnet Mask: | 11111111.11111111.11111111.00000000 |
IPv4 CIDR Reference Cheat Sheet
Click any row to test prefix in calculator immediately.
| CIDR | Subnet Mask | Total IPs | Usable Hosts |
|---|---|---|---|
/32 | 255.255.255.255 | 1 | 1 (Host) |
/31 | 255.255.255.254 | 2 | 2 (P2P Link) |
/30 | 255.255.255.252 | 4 | 2 |
/29 | 255.255.255.248 | 8 | 6 |
/28 | 255.255.255.240 | 16 | 14 |
/27 | 255.255.255.224 | 32 | 30 |
/26 | 255.255.255.192 | 64 | 62 |
/24 | 255.255.255.0 | 256 | 254 |
/23 | 255.255.254.0 | 512 | 510 |
/20 | 255.255.240.0 | 4,096 | 4,094 |
/16 | 255.255.0.0 | 65,536 | 65,534 |
/8 | 255.0.0.0 | 16,777,216 | 16,777,214 |
About This Tool
Takes an IPv4 address with a CIDR prefix (e.g. 192.168.1.100/24) and derives the network address, broadcast address, usable host range, netmask, wildcard mask, and binary bitmask. These calculations are essential for network planning, AWS VPC sizing, Docker networks, and firewall rule auditing.
Supports all IPv4 CIDR blocks from /0 through /32, including special point-to-point RFC 3021 /31 subnets and single host /32 routes.
Key Features
- Live calculation: Every result updates in real-time as you type, without page reloads or submit buttons.
- Interactive CIDR reference: Side-by-side CIDR cheat sheet lets you click any prefix to test network allocations.
- Eight-metric analysis: Calculates network, broadcast, usable range, host counts, netmask, wildcard mask, class, and binary mask.
- Binary bitmask visualizer: Visualizes all 32 bits showing network prefix bits and host address bits.
- RFC 3021 support: Correctly accounts for /31 point-to-point subnets where both addresses are usable hosts.
- 100% Client-side: All binary bitwise operations run in local browser memory with zero network latency.
Frequently Asked Questions
Does the host portion of the input IP address matter?
No. Enter any IP within the target block (e.g. 192.168.1.100/24). The calculator applies bitwise AND with the subnet mask to accurately derive the base network address.
How are edge prefixes /31 and /32 calculated?
/31 treats both addresses as usable hosts per RFC 3021 point-to-point links. /32 represents a single host route with no broadcast split.
What does the IP Class indicator represent?
The legacy Class A, B, C, D, or E label is derived from the first octet per pre-CIDR standards. It is provided for historical reference and does not restrict modern CIDR routing.
What is a wildcard mask and where is it used?
A wildcard mask is the bitwise inverse of the subnet mask (e.g. 0.0.0.255 for /24). It is commonly required in Cisco IOS Access Control Lists (ACLs) and OSPF routing configurations.
Is any network address or CIDR query transmitted over the internet?
No. All bitwise conversions execute entirely inside your local browser. No IP addresses or queries are ever sent to an external server.
