IP Subnet Calculator
Calculate network address, broadcast address, subnet mask and usable hosts for an IPv4 CIDR block.
/31 and /32 have no usable host addresses.
What is IP Subnet Calculator?
An IPv4 subnet is a logical division of a network identified by an IP address paired with a CIDR prefix, such as /24. The prefix defines how many leading bits are fixed for the network, and the remaining bits address hosts within the subnet.
From any host IP and prefix you can derive the network address, the broadcast address, the subnet mask, and the number of usable host addresses, all of which are required for configuring routers and planning address space.
How does the IP Subnet Calculator work?
The subnet mask has its prefix high bits set to 1; the network address is obtained by masking (ANDing) the IP with this mask.
The broadcast address sets all host bits to 1, and the usable hosts count subtracts the network and broadcast addresses from the total block size, except for /31 and /32 which have none.
How to use the IP Subnet Calculator?
- Enter a valid IPv4 address, such as 192.168.1.0.
- Choose the CIDR prefix from 0 to 32 with the slider, commonly 24 for home networks.
- Read the network and broadcast addresses for routing and VLSM planning.
- Check the subnet mask and usable host count to size your subnet correctly.
Example
Try the calculator with your own numbers
- Enter your values in the input fields above.
- Adjust the values to match your situation.
- The result updates instantly as you change the inputs.
Benefits of using the IP Subnet Calculator
- Determine the correct network and broadcast addresses instantly.
- Know exactly how many hosts a given CIDR block can support.
- Avoid misconfiguration and wasted address space when subnetting.
Who should use the IP Subnet Calculator?
- Students and professionals who need fast, accurate results.
- Anyone who wants to verify a manual calculation.
- People who prefer a quick answer over working it out by hand.
Tips for getting the most out of the IP Subnet Calculator
- Double-check the values you enter before relying on the result.
- Use the calculator to verify manual calculations or estimates.
- Bookmark the page if you use it regularly.
Frequently Asked Questions
What does /24 mean?
A /24 prefix means the first 24 bits identify the network. It provides 256 total addresses, of which 254 are usable for hosts once the network and broadcast addresses are removed.
Why do /31 and /32 have no usable hosts?
A /31 block has only 2 addresses and a /32 only 1, leaving no room after reserving the network and broadcast addresses. RFC 3021 permits /31 for point-to-point links, and /32 is used for a single host route.
What is a subnet mask?
A subnet mask is a 32-bit number that separates the network portion of an address from the host portion. For example, /24 corresponds to the mask 255.255.255.0.
When you need a trustworthy figure fast, the IP Subnet Calculator delivers it in seconds — free, private, and ready whenever you are.
Related Calculators
EMI Calculator
Calculate monthly EMI, total interest and total amount for any loan.
SIP Calculator
Calculate the future value of your Systematic Investment Plan.
PPF Calculator
Calculate returns on Public Provident Fund.
GST Calculator
Calculate GST amount for any product or service.
Income Tax Calculator
Calculate your payable income tax.
Compound Interest Calculator
Calculate compound interest with ease.