Subnet Calculator

Calculate network address, broadcast, host range, wildcard mask, and binary representations from any IP/CIDR or subnet mask.

⚙ Enter IP Address & Subnet

— OR use CIDR notation —
📊 Subnet Results
🔢 Binary Representations
Field Decimal Binary
📋 CIDR Reference Table
CIDR Subnet Mask Wildcard Total IPs Usable Hosts Class

🔷 About IPv6 Subnetting

This calculator handles IPv4 addresses (32-bit). IPv6 uses 128-bit addresses and a different subnetting model — prefix notation still applies (e.g., 2001:db8::/32) but the calculations differ substantially.

IPv6 does not use broadcast addresses. The equivalent of a network address is the subnet prefix, and the "last" address is the anycast/subnet-router anycast address. Host enumeration is impractical beyond /64 which alone provides 264 ≈ 18.4 quintillion addresses.

A dedicated IPv6 subnet calculator will be added to UpTools soon.

🔑 What is a Subnet?

A subnet (subnetwork) divides a larger IP network into smaller, manageable segments. The subnet mask determines which part of an IP address identifies the network and which part identifies the host.

📐 CIDR Notation

CIDR (Classless Inter-Domain Routing) uses a suffix like /24 to indicate how many bits are in the network portion. /24 means 24 network bits and 8 host bits = 256 addresses.

🏠 Usable Hosts

The first address (network address) and last address (broadcast) are reserved, so usable hosts = 2ⁿ − 2, where n is the number of host bits. A /30 gives only 2 usable hosts — perfect for point-to-point links.

🃏 Wildcard Mask

The wildcard mask is the inverse of the subnet mask. It's widely used in ACLs and routing protocols (e.g., OSPF) to specify address ranges. For a /24 mask (255.255.255.0) the wildcard is 0.0.0.255.

✅ Do's and ❌ Don'ts

✅ Do's

  • ✅ Do use this tool to save time on manual calculations.
  • ✅ Do double-check your inputs for accuracy.
  • ✅ Do share results with teammates using the Share feature.
  • ✅ Do bookmark this tool for quick access.

❌ Don'ts

  • ❌ Don't enter sensitive personal data — this tool doesn't store anything.
  • ❌ Don't use results as professional financial/legal/medical advice.
  • ❌ Don't forget to verify critical calculations with official tools.
  • ❌ Don't assume results are guarantees — they are estimates.

Frequently Asked Questions

Is this tool free to use?

Yes. All UpTools calculators are completely free, with no sign-ups required.

Is my data private?

Yes. All calculations run locally in your browser. Nothing is uploaded to any server.

Does it work on mobile?

Yes. All tools are mobile-responsive and work on any device — phone, tablet, or desktop.

Can I use this offline?

Most tools work offline after the initial page load. No internet needed for calculations.

📐 How This Tool Works

This tool computes results entirely in your browser using JavaScript. No data is sent to any server, ensuring your privacy.

Results update instantly as you type — no waiting for server responses.

Also try: Calculator · Converter · Generator