IPv4 Subnet Calculator — Free Online Tool
Network, broadcast, masks, hex, IP class, binary map and a subnet splitter.
Quick:
Network Details
Binary Visualisation
■ network bits ■ host bits
IP Class & Address Type
Subnet Splitter
Special IPv4 Address Ranges
| Range | Type | Description |
|---|---|---|
| 10.0.0.0/8 | Private | Class A private (RFC 1918) |
| 172.16.0.0/12 | Private | Class B private (RFC 1918) |
| 192.168.0.0/16 | Private | Class C private (RFC 1918) |
| 127.0.0.0/8 | Loopback | Localhost |
| 169.254.0.0/16 | APIPA | Link-local / DHCP failure |
| 100.64.0.0/10 | Shared | Carrier-grade NAT (RFC 6598) |
| 224.0.0.0/4 | Multicast | Class D multicast |
| 240.0.0.0/4 | Reserved | Class E reserved |
| 192.0.2.0/24 | Docs | TEST-NET-1 (RFC 5737) |
| 255.255.255.255/32 | Broadcast | Limited broadcast |
About IPv4 Subnet Calculator
This complete IPv4 Subnet Calculator turns an IP address and CIDR prefix into everything you need to plan or troubleshoot a network: network and broadcast addresses, usable host range, subnet and wildcard masks, total and usable host counts, hexadecimal forms, the IP class, and the address type with its RFC and routing properties.
It also includes a binary bit-map that visualises which bits are network and which are host, plus a subnet splitter that divides a network into equal subnets — all running locally in your browser for instant, private results.
How to Use IPv4 Subnet Calculator
- Enter an IPv4 address (or use a quick preset).
- Choose the CIDR prefix.
- Click Calculate to see the full breakdown and binary map.
- Optionally use the subnet splitter to divide the network into equal subnets.
Key Features
Network, broadcast, first/last host and host counts
Subnet mask, wildcard mask, CIDR and hex forms
IP class and address type (private/public/special) detection
Binary bit-map with network/host highlighting
Subnet splitter into equal subnets
Special IP ranges and subnet mask reference tables
100% client-side — nothing is uploaded
Frequently Asked Questions
What does this subnet calculator show?
Enter an IPv4 address and a CIDR prefix to get the network and broadcast addresses, first and last usable hosts, subnet mask, wildcard mask, total and usable host counts, hex representations, IP class, address type (private/public/etc.), and a binary bit-map.
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) writes a network as address/prefix, e.g. 192.168.1.0/24, where the number is how many leading bits are the network portion. /24 equals subnet mask 255.255.255.0 with 254 usable hosts.
How does the subnet splitter work?
Choose how many equal subnets to divide your network into (a power of two). The tool calculates the new prefix length and lists each resulting subnet's network address and host range.
What is a wildcard mask?
A wildcard mask is the bitwise inverse of the subnet mask, used in Cisco ACLs and OSPF. For 255.255.255.0 the wildcard is 0.0.0.255.
Is my input sent anywhere?
No. Every calculation runs locally in your browser; nothing you enter is uploaded or stored.