IPv4 Subnet Calculator

Runs in browser

Calculate IPv4 subnets: network address, broadcast, host range, subnet mask.

Calculate IPv4 subnet masks, network addresses, broadcast addresses, host ranges, and more. Supports CIDR notation. Split subnets into N equal parts. Pure browser-based, no data sent to server.

IPv4 Subnet Calculator tool

/
Network address192.168.1.0
Subnet mask255.255.255.0
Wildcard mask0.0.0.255
Broadcast address192.168.1.255
First usable host192.168.1.1
Last usable host192.168.1.254
Total hosts256
Usable hosts254
CIDR notation192.168.1.0/24
IP classClass C
#NetworkFirst HostLast HostBroadcastHosts
1192.168.1.0/26192.168.1.1192.168.1.62192.168.1.6362
2192.168.1.64/26192.168.1.65192.168.1.126192.168.1.12762
3192.168.1.128/26192.168.1.129192.168.1.190192.168.1.19162
4192.168.1.192/26192.168.1.193192.168.1.254192.168.1.25562

Common Subnets Reference

CIDRUsable HostsExample
/816,777,21410.0.0.0/8
/1665,534192.168.0.0/16
/24254192.168.1.0/24
/25126192.168.1.0/25
/2662192.168.1.0/26
/2814192.168.1.0/28
/296192.168.1.0/29
/302192.168.1.0/30
/312 (no host/bcast)192.168.1.0/31
/321 (host route)192.168.1.1/32

Click a row to set the CIDR prefix.

🔒 Runs in your browser · No uploads · Your data never leaves your device

How to use

  1. Enter an IP and CIDR prefix

    Type any IPv4 address and select a prefix length from 0 to 32 using the dropdown.

  2. Read the results

    Network address, subnet mask, wildcard, broadcast, first/last usable host, and host count are shown instantly.

  3. Split into subnets

    Enter how many subnets to split into — the table shows each subnet's network, host range, and broadcast.

Common use cases

  • Planning a VPC or office network — Calculate usable host ranges for /24 or /16 blocks when designing network segments for cloud infrastructure or on-premises environments.
  • Splitting a network into subnets — Use the subnet split feature to divide a /20 block into equal /24 subnets for multi-team or multi-zone network layouts.

Examples

  • Office network

    Calculate 192.168.1.0/24.

    Output
    Network: 192.168.1.0 | Broadcast: 192.168.1.255 | Usable hosts: 254

Frequently asked questions

What is a subnet mask?
A subnet mask defines which portion of an IP address is the network and which is the host. /24 corresponds to 255.255.255.0 — the first 24 bits are the network.
What are /31 and /32 subnets?
/31 has 2 addresses with no broadcast — used for point-to-point links (RFC 3021). /32 is a single host route.
What is a wildcard mask?
The wildcard mask is the inverse of the subnet mask. It is used in ACL rules and OSPF configuration. For /24, the wildcard is 0.0.0.255.

Key concepts

CIDR
Classless Inter-Domain Routing — a notation like 192.168.1.0/24 that combines an IP address and a prefix length to define a network block.
Broadcast address
The last IP address in a subnet, used to send packets to all hosts in the network. It cannot be assigned to an individual host.

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