IPv4 Subnet Calculator
Calculate network address ranges, subnet masks, wildcard masks, usable host capacities, and binary layouts instantly.
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Subnetting Formula Reference
1. Network & Broadcast
Network Address is calculated via bitwise AND: $\text{IP} \mathbin{\&} \text{Mask}$. Broadcast Address is calculated via bitwise OR with inverted mask: $\text{Network} \mathbin{|} \sim\text{Mask}$.
2. Usable Host Capacity
For prefixes $\le 30$, usable hosts = $2^{(32 - \text{CIDR})} - 2$, reserving the network and broadcast IPs. For $/31$ and $/32$, specialized point-to-point and loopback rules apply.
How to use IPv4 Subnet Calculator
- Enter or paste the values requested in the input fields.
- Choose any options provided, then run an action button if the tool requires one.
- Review the result and copy or adjust it as needed.
IPv4 Subnet Calculator features
- Available tool controls: Calculate Subnet.
- Input and option fields: IPv4 Address:, Subnet Prefix (CIDR):, Subnet Calculation Summary:.
Frequently Asked Questions (FAQ)
A wildcard mask is the inverse of a subnet mask (where 0s become 1s and 1s become 0s), commonly used in router Access Control Lists (ACLs) to specify network ranges.
The first usable IP is always the network address plus 1, and the last usable IP is the broadcast address minus 1 (for standard subnets up to $/30$).
Yes. All subnet computations occur directly inside your browser using client-side JavaScript execution.