192.168.1.10/24
- Subnet mask
- 255.255.255.0
- Wildcard mask
- 0.0.0.255
- Broadcast
- 192.168.1.255
- Usable range
- 192.168.1.1 - 192.168.1.254
- Usable addresses
- 254
Subnet Calculator
Use this free subnet calculator to convert an IPv4 address and CIDR prefix into subnet mask, wildcard mask, network, broadcast, and usable addresses.
Inputs explained Result checks Example values Runs in your browser
Formula steps
- Convert the IPv4 address and CIDR prefix into 32-bit values.
- Build the subnet mask from the prefix length.
- Use bitwise network and wildcard math to find network, broadcast, and usable range.
How to use the Subnet Calculator
- Enter the requested dates, times, grades, dimensions, network values, password options, or units.
- Check the assumptions shown on the page, especially school scales, payroll rules, concrete waste, subnet type, or security handling.
- Press the calculate button to see the answer, supporting metrics, and formula steps.
- Use examples, recent answers, or copy the result while keeping the estimate limits in mind.
What people use it for
Find the network and broadcast address for an IPv4 CIDR block.
Convert a prefix length such as /24 into a dotted decimal subnet mask.
Check usable host range and address count.
Practice subnetting for networking, security, or developer work.
Quick examples
Home LAN
192.168.1.10/24Network 192.168.1.0, usable 192.168.1.1-192.168.1.254
Small subnet
10.0.5.17/2816 total addresses
Point-to-point
172.16.0.8/312 usable /31 addresses
Need the guide or a nearby tool?
Need a slower walkthrough, a related calculator, or the full library? These links keep you close to the task you started.
- How to use the Subnet Calculator See slower examples, input meanings, formula notes, result limits, and mistakes to avoid.
- Developer Tools Browse related calculators and utilities in the same category.
- Developer Utility Tools Hub Compare this with the nearby tools and checks in the same job path.
- Calculator and utility guides Find more guides that use real tool inputs and example numbers.
- All free tools Search every live tool, converter, calculator, AI helper, and browser utility.
Frequently asked questions
Plain-language answers about when to use the tool, what it does with your inputs, what to double-check, and how privacy works.
When should I use the Subnet Calculator?
Use it when your task matches one of these common needs: Find the network and broadcast address for an IPv4 CIDR block. Convert a prefix length such as /24 into a dotted decimal subnet mask. It works best when you already know the text, code, URL, mode, format, or technical setting the page asks for.
What is the Subnet Calculator doing with my inputs?
In plain language: The calculator converts IPv4 octets to a 32-bit number, builds the CIDR subnet mask, then uses bitwise network and wildcard math. The examples on the page are there so you can compare your inputs with a filled-out example before copying the answer.
What do the main Subnet Calculator inputs mean?
The main inputs are usually text, code, a URL, a number base, or a mode setting. Paste only the part you want the tool to work on and compare the output with the examples.
How should I read the Subnet Calculator answer?
Read the output next to your original input. If the tool changes format, units, encoding, spacing, or capitalization, compare a small sample before copying the whole result into another app.
What should I double-check before trusting the answer?
This tool covers IPv4 CIDR math. It does not configure routers, validate a live network, or handle IPv6 subnets. Also check the selected mode, input format, encoding, and whether the text includes private keys, passwords, or sensitive data.
Why do /31 and /32 subnets look different?
Most IPv4 subnets reserve the first address as the network address and the last address as broadcast. A /31 is commonly used for point-to-point links with two usable addresses, and a /32 represents one exact host address.
Can this calculator choose the best subnet size for me?
It shows the math for one IPv4 CIDR block, but it does not design the network. Pick a prefix after you know the device count, growth room, provider-reserved addresses, routing rules, firewall rules, and whether the environment treats network and broadcast addresses normally.
Does the site save what I enter?
No. The tool runs in your browser tab. Your recent answers stay only on the page while you use it, and they are not sent to a server.