IPv4 Subnet Mask & CIDR Calculator
Calculate usable host IP count, wildcards, and netmask octets from CIDR prefix length (/0 to /32).
- 100% free
- Private in browser
- No signup
- No watermarks
Total IP Addresses
256
Usable Host Addresses
254
Last Subnet Octet (255.255.255.X)
0
Rate this tool
Be the first to rate — helps others and improves this page.
About IPv4 Subnet Mask & CIDR Calculator
Calculate usable host IP count, wildcards, and netmask octets from CIDR prefix length (/0 to /32).
How to use IPv4 Subnet Mask & CIDR Calculator
- Enter your required input values into the fields.
- View the automatically calculated results in real time.
Key features
- Instant client-side calculation
- Real-time updates without page reloads
- Private and secure: zero data leaves your browser
Frequently asked questions
- Is this calculation free and private?
- Yes, 100% of calculations execute locally in your web browser. No inputs or personal data are stored or transmitted.