IPv4 Subnet Calculation

Enter IP Address and Netmask

IP Address:
IP Type:
IP Class:
Netmask:
Binary Netmask:
Wildcard Mask:
CIDR Notation:
Network Prefix (Decimal):
Subnet Bits:
Host Bits:
Subnet ID (Network Address):
Broadcast Address:
Network Address (Binary):
Broadcast Address (Binary):
First Usable Host:
Last Usable Host:
Usable Host Range:
Total number of hosts:
Number of usable hosts:
IP in Hex:
Network in Hex:
Broadcast in Hex:
Subnet Increment (Block Size):
Number of Subnets for Hosts:

Example IP Address Inputs

IP Version Example Input Format / Description
IPv4 172.31.170.140 255.255.252.0 Subnet Mask
IPv4 192.168.4.215/28 CIDR Notation
IPv4 172.16.45.45 0.0.15.255 Wildcard Mask
IPv4 10.45.50.60 #52 Calculates a network with 52 hosts

Tip: Enter IPv4 in dotted decimal format, with optional CIDR or subnet mask. IPv6 requires prefix length. Ipv6 - analysis coming soon..

🧮 Manual Calculation Guide

IP Address Start with the IP address you want to analyze, e.g., 192.168.1.10. This identifies a host in a network.
Netmask Determines which portion of the IP is the network and which is host. Example: 255.255.255.0. Formula: Network bits = count of consecutive 1s in binary netmask. Host bits = remaining bits.
Binary IP Convert each octet to 8-bit binary. Example: 192.168.1.10 → 11000000.10101000.00000001.00001010.
Binary Netmask Convert netmask to binary to visualize network vs host bits. Example: 255.255.255.0 → 11111111.11111111.11111111.00000000.
Wildcard Mask Inverse of netmask: Wildcard = 255.255.255.255 - Netmask. Example: 255.255.255.0 → 0.0.0.255. Used in ACLs/firewalls.
CIDR Notation Count number of 1s in netmask: /24 means 24 network bits. Example formula: 255.255.255.0 → 11111111.11111111.11111111.00000000 → /24.
Subnet Bits Extra bits borrowed from host portion to create subnets. Example: original /24, borrow 2 bits → subnet mask /26 → 4 subnets.
Host Bits Remaining bits after network & subnet bits. Determines hosts per subnet. Formula: Host bits = 32 - Network bits - Subnet bits.
Subnet ID / Network Address Logical AND between IP and netmask:
IP: 192.168.1.130 → 11000000.10101000.00000001.10000010
Netmask: 255.255.255.192 → 11111111.11111111.11111111.11000000
Network: 192.168.1.128 → 11000000.10101000.00000001.10000000
First Usable Host Add 1 to network address: 192.168.1.128 + 1 → 192.168.1.129
Last Usable Host Subtract 1 from broadcast address: 192.168.1.191 - 1 → 192.168.1.190
Broadcast Address Set all host bits to 1:
Network: 192.168.1.128 → 11000000.10101000.00000001.10000000
Broadcast: 192.168.1.191 → 11000000.10101000.00000001.10111111
Total / Usable Hosts Total hosts = 2^(host bits).
Usable hosts = Total - 2 (network & broadcast).
Example: host bits = 6 → total 64, usable 62.
IP Class Based on first octet:
Class A: 1-126, B: 128-191, C: 192-223, D: 224-239 (Multicast), E: 240-254 (Experimental)
IP Type Determine if IP is Private (RFC1918), Public, Loopback (127.0.0.0/8), or Link-Local (169.254.0.0/16)
Network / Broadcast in Binary Convert network and broadcast addresses to binary for visualization. Useful for ACLs and firewall rules.
IP / Network / Broadcast Hex Convert each octet to hexadecimal. Example: 192.168.1.10 → 0xC0A8010A
Subnet Increment / Block Size Number of IPs in each subnet = 2^(host bits). Example: /26 → 2^(32-26) = 64 addresses per subnet
Number of Subnets for Hosts Maximum subnets you can create = 2^(borrowed subnet bits). Example: borrow 2 bits → 4 subnets
Host Allocation Planning Helps plan which IPs go into which subnet, avoiding overlaps. Useful for large networks or VLAN segmentation.