Does the calculator look up the IP address?
No. It performs deterministic IPv4 arithmetic only. It does not query ownership, location, DNS, or any external service.
CIDR
Network
IPv4 Subnet Calculator
Calculate an IPv4 network address, broadcast address, subnet mask, wildcard mask, usable host range, and capacity from CIDR notation — entirely in your browser.
● IPv4 / CIDR
Calculate an IPv4 subnet
Enter an IPv4 address with a CIDR prefix. Every bitwise calculation stays in this browser.
Output
Your result will appear here.
Three simple steps
How to use IPv4 Subnet Calculator
- 01
Enter an IPv4 address with a CIDR prefix.
- 02
Calculate the network boundaries locally.
- 03
Copy the mask, range, or capacity you need.
Privacy first
Tool data and site requests stay separate
Tool input and results are processed in temporary state for the current page. The TabPebble application does not send them to a server, write them to a database, or create processing history. Pages and code still load through ordinary network requests. Your browser may restore a tab, while downloads and clipboard copies remain on the device until you remove or replace them.
- No tool-task upload
- No account
- No processing history
FAQ
Frequently asked questions
Is this tool free?
Yes. Core tools are free to use and do not require an account.
Does tool input go to a server?
No. The TabPebble application performs the tool task in your browser and does not put input into site requests; ordinary page and code requests still reach the hosting service.