IP Subnet Calculator
Options
Subnet summary
Binary view
What is an IP Subnet Calculator?
An IP Subnet Calculator helps you calculate the network details of an IPv4 address and CIDR block.
It is useful for networking, DevOps, server setup, firewall rules, cloud infrastructure, and troubleshooting address ranges.
How to use the IP Subnet Calculator
- Enter an IPv4 address and CIDR, such as 192.168.1.10/24.
- You can also fill the IP and CIDR fields separately.
- Click Calculate to see the network address, broadcast, subnet mask, and usable range.
- Copy the summary output if needed.
Tips
- A /24 network usually has 256 total addresses and 254 usable hosts.
- A /32 represents a single IPv4 address.
- A /31 is often used for point-to-point links.
- The wildcard mask is useful for ACL and router configurations.
Subnet planning checks
Avoid overlapping ranges
Check whether a planned subnet overlaps with VPN, office, VPC, Kubernetes, or database allowlist ranges before using it.
Size for growth
Leave enough usable hosts for future services, load balancers, NAT gateways, containers, and temporary environments.
Use narrow allowlists
For firewall and database access, prefer the smallest CIDR range that matches the real source addresses.
Document private ranges
Record why each private range exists so future network migrations do not accidentally reuse the same address space.
Related guides
Learn the workflow behind this tool and what to check next.
IP subnet basics for developers
A practical subnetting guide for reading CIDR notation, checking network ranges, planning private networks, and avoiding address conflicts.
How to troubleshoot DNS records for a domain
A practical DNS checklist for website hosting, email records, domain verification, nameserver changes, SSL certificates, and reverse DNS.
How to validate a domain before launch
A launch workflow for confirming DNS records, domain ownership signals, SSL coverage, and security headers on the public endpoint.
Subnet checks before assigning or routing an IP range
Verify address family, prefix length, reserved addresses, and the platform's routing model before applying calculated boundaries.
Network boundaries
Confirm network, broadcast, first and last usable addresses, total size, and whether the environment reserves additional addresses.
Prefix interpretation
Keep CIDR prefix and subnet mask aligned and avoid applying IPv4 host assumptions directly to IPv6 networks.
Overlap detection
Compare proposed ranges with VPCs, VPNs, containers, offices, partner networks, and future expansion space.
Routing and access
Review route tables, gateways, NAT, firewalls, ACLs, and cloud-specific reservations before deployment.
Privacy and usage
Built for quick checks without an account
Toolinix tools are designed for short developer tasks: paste a safe sample, inspect the result, copy what you need, and move on.
No login required
You can use the tools without creating an account, subscribing to a newsletter, or saving a workspace.
Local when possible
Formatters, generators, encoders, and text utilities generally run in your browser. Network diagnostics may need a server-assisted lookup to check public URLs, domains, or IPs.
Keep secrets out
Do not paste production passwords, private keys, access tokens, customer records, or regulated data into online tools unless your own security policy allows it.
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