IPv4 CIDR Calculator Online — Subnet Mask, Hosts & Network IP
Compute complete IPv4 subnet details from CIDR notation (/0 to /32). Color-coded 32-bit binary breakdown and IP class identification.
Runs in your browser. Your files never leave your device. See how to check
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How to do it
- 1Step 1: Open IPv4 CIDR Subnet Calculator & Bitmask Visualizer and add your input
Type your numbers or text, add your file, or pick the options you need. Nothing is uploaded: everything stays in your browser.
- 2Step 2: What IPv4 CIDR Subnet Calculator & Bitmask Visualizer does
Calculate subnet mask, network IP, broadcast address, usable IP range, total hosts, and 32-bit binary representation.
- 3Step 3: Read the result and compare
The result appears at once. Change one value to see how the answer moves, then keep the figure that fits your case.
- 4Step 4: Copy or save it
Copy the result or download it. For an important decision, confirm it with the official source or an adviser.
About this tool
Essential networking utility for DevOps engineers, cloud architects, and system administrators. Input any IPv4 address and select a CIDR prefix (/0 to /32) to compute subnet mask, wildcard mask, network address, broadcast address, first usable host, last usable host, total IP capacity, and usable host count. Includes visual color-coded 32-bit binary mask showing network bits in green and host bits in red.
Tips for best results
Take a moment to read the options before you start, and try the tool with a small sample first. Everything runs in your browser on your own device, so nothing you type or add is uploaded, and closing the tab clears it. If something does not look right, reload the page and try again, or use the report link on this page to tell us what went wrong so we can fix it. If a result still looks wrong, change one value at a time to see which box matters most. Bookmark this page if you will need the tool again.
Quick facts
- Category: Documents
- Works in your browser, no sign-up, no upload.
- Your input stays on your device.
- Available in many languages.
- Content last reviewed:
Frequently asked questions
What is CIDR notation?
Classless Inter-Domain Routing (CIDR) represents an IP address and its subnet mask prefix length (e.g., 192.168.1.0/24 indicates 24 network bits).
How many usable hosts are in a /24 subnet?
A /24 subnet provides 256 total IP addresses, with 254 usable hosts (network address .0 and broadcast address .255 are reserved).
What is a wildcard mask?
A wildcard mask is the bitwise inverse of the subnet mask, commonly used in Cisco router Access Control Lists (ACLs) and OSPF configs.
Does the calculator identify IP classes?
Yes. It automatically identifies Class A, B, C, Multicast (D), or Experimental (E) address spaces.