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IP Subnet Calculator
Work out the network, broadcast, host range and masks for any IPv4 CIDR block.
IPv4 subnet calculator
Network: —
Broadcast: —
First usable host: —
Last usable host: —
Total addresses: —
Usable hosts: —
Netmask: —
Wildcard mask: —
Range type: —
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How to use the IP Subnet Calculator
- Type an IPv4 address with a prefix such as 192.168.1.10/24 into the box.
- Press Calculate to work out the network, broadcast and host range.
- Read the masks and the binary view, then copy the summary if you need it.
Features
- Network and broadcast address
- First and last usable host in the block
- Netmask, wildcard mask and prefix length
- Binary view of address, mask and range
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Frequently Asked Questions
Common questions about the free online ip subnet calculator.
The number after the slash is the prefix length, so a slash twenty four means twenty four
network bits and eight host bits.
It is the first address in the block, where every host bit is zero, and it names the subnet
itself.
It is the last address in the block, where every host bit is one, and it reaches every host
on that subnet.
For prefixes up to thirty, take two to the power of the host bits and subtract two for the
network and broadcast.
On a point to point link both addresses are usable, so no address is lost to the network or
broadcast role.
It is the inverse of the netmask, so a zero bit marks a network position and a one bit marks
a host position.
Yes. Write the address and the mask separated by a space, or use the slash form, and the
prefix is worked out.
No. All of the arithmetic runs inside your browser, so nothing is uploaded or stored.
Last updated: October 10, 2026