What is a subnet mask?
A subnet mask identifies which bits of an IPv4 address belong to the network portion and which belong to the host portion.
Networkclientbetav0.1.0
Subnet Calculator
Calculate IPv4 subnet information.
Subnet calculations happen locally in your browser.
What is Subnet Calculator?
Subnet Calculator calculates IPv4 network information from an IP address and CIDR prefix. It provides the network address, broadcast address, subnet mask, wildcard mask, usable host range, and address counts.
How to use Subnet Calculator
- Enter an IPv4 address followed by a CIDR prefix, for example 192.168.1.10/24.
- Select Calculate subnet.
- Review the network address, broadcast address, subnet mask, and wildcard mask.
- Check the usable host range and total address count.
- Copy all calculated values when needed.
IPv4 CIDR notation
CIDR notation combines an IPv4 address with a prefix length such as /24. The prefix indicates how many leading bits belong to the network portion of the address.
Usable host ranges
Traditional IPv4 subnets from /0 through /30 reserve the network and broadcast addresses, leaving the addresses between them for hosts. /31 networks are commonly used for point-to-point links, while /32 represents a single host route.
Private IPv4 addresses
The calculator identifies the RFC 1918 private ranges 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. Addresses outside those ranges are labeled public by this tool.
Privacy and local processing
IPv4 and subnet calculations are performed locally in your browser. BOYGR Tools does not need to send the entered IP address to a server.
Frequently asked questions
What is a wildcard mask?
A wildcard mask is the bitwise inverse of the subnet mask and is commonly used in networking rules such as access control lists.
Why does a /24 have 254 usable hosts?
A /24 contains 256 total addresses. In traditional subnetting, one address is reserved for the network and one for broadcast, leaving 254 usable host addresses.
Does BOYGR Tools send my IP address to a server?
No. Subnet calculation happens locally in your browser.