Subnet Calculator
Enter an IP, CIDR, or netmask to view network address, broadcast address, usable host range, and host count.
Convert between CIDR, prefix length, and netmask while showing network address, broadcast address, first or last usable host, and available host count.
Useful for VPC planning, router and switch configuration, cloud server setup, and everyday networking work.
Convert CIDR, prefix length, and netmask while directly viewing network address, broadcast, and usable host ranges.
Enter a CIDR block directly, or provide an IP address with either a prefix length or a netmask.
Summary
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Common use cases
- Use this page when configuring servers, switches, firewalls, or virtual networks and you want to confirm subnets and host ranges quickly.
- It is useful for checking conversions between CIDR, prefix length, and dotted netmask without doing the math by hand.
- For learning networking, preparing interviews, or planning address space, a subnet calculator makes the structure easier to understand than memorizing formulas alone.