NETWORK, DATA, AND DIGITAL MEDIA
IPv4 Subnet Calculator
Calculate an IPv4 network address, subnet mask, broadcast address, total address count, and traditional usable-host count from CIDR notation.
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Enter your values and select Calculate. Your result stays on this device.
How it works
The prefix creates a 32-bit network mask; bitwise AND yields the network and the inverted host mask yields the broadcast address.
Assumptions
Uses IPv4 and CIDR only. Host usability for /31, /32, point-to-point links, cloud networks, reserved ranges, and provider policies can differ.
About this calculator
This IPv4 subnet calculator targets the common U.S. IT search for a quick network-range check. It keeps the input address and CIDR prefix separate and returns the core dotted-decimal values together.
How to use it
- Enter a valid dotted-decimal IPv4 address.
- Enter a CIDR prefix from 0 through 32.
- Calculate the network, mask, broadcast, and address counts.
- Verify the result against the real platform before changing a production network.
Use case
subnet calculator: a clear planning check
Enter a dotted-decimal IPv4 address and prefix to calculate the network range using visible CIDR rules before verifying a production plan.
Check an IPv4 CIDR network, mask, broadcast address, and address count.
Source and update
Last reviewed: 2026-08-22
IETF RFC 4632 — Classless Inter-domain RoutingFrequently asked questions
What does /24 mean?
It means the first 24 bits are the network prefix, corresponding to the mask 255.255.255.0.
Why are two addresses often subtracted from usable hosts?
Traditional subnets reserve the network and broadcast addresses, although /31, /32, and platform-specific rules differ.
Does this support IPv6?
No. This calculator is limited to IPv4 CIDR.
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