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Subnet Calculator
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Subnet Calculator

Calculate subnets from CIDR notation. Free subnet calculator with host range, broadcast, and mask conversion.

Works Offline100% Free

Processed 100% locally in your browserPrivate & Safe

Subnet Calculator runs entirely on your device using Web API standards. No data is ever uploaded to UtilixVerse servers.

Your Input
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Browser
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Result
No Server UploadsNo Account RequiredWorks OfflineZero Data Logging

Subnet Input

Network Address
192.168.1.0
Broadcast Address
192.168.1.255
Subnet Mask
255.255.255.0
Usable Host Range
192.168.1.1 – 192.168.1.254
Total Addresses
256
Usable Hosts
254

Split This Network Into Subnets

Subnet prefix

Splitting 192.168.1.0/24 into 16 subnets of 16 addresses (14 usable) each.

Subnet Table

Private (RFC 1918)
#NetworkBroadcastUsable RangeHosts
1192.168.1.0/28192.168.1.15192.168.1.1 – 192.168.1.1414
2192.168.1.16/28192.168.1.31192.168.1.17 – 192.168.1.3014
3192.168.1.32/28192.168.1.47192.168.1.33 – 192.168.1.4614
4192.168.1.48/28192.168.1.63192.168.1.49 – 192.168.1.6214
5192.168.1.64/28192.168.1.79192.168.1.65 – 192.168.1.7814
6192.168.1.80/28192.168.1.95192.168.1.81 – 192.168.1.9414
7192.168.1.96/28192.168.1.111192.168.1.97 – 192.168.1.11014
8192.168.1.112/28192.168.1.127192.168.1.113 – 192.168.1.12614
9192.168.1.128/28192.168.1.143192.168.1.129 – 192.168.1.14214
10192.168.1.144/28192.168.1.159192.168.1.145 – 192.168.1.15814
11192.168.1.160/28192.168.1.175192.168.1.161 – 192.168.1.17414
12192.168.1.176/28192.168.1.191192.168.1.177 – 192.168.1.19014
13192.168.1.192/28192.168.1.207192.168.1.193 – 192.168.1.20614
14192.168.1.208/28192.168.1.223192.168.1.209 – 192.168.1.22214
15192.168.1.224/28192.168.1.239192.168.1.225 – 192.168.1.23814
16192.168.1.240/28192.168.1.255192.168.1.241 – 192.168.1.25414

VLSM Splitter — divide by host count

List the hosts each subnet needs. The plan allocates the smallest blocks that fit, largest requirement first.

Free Subnet Calculator — Host Ranges, Broadcasts & Subnet Tables

Welcome to the UtilixVerse Subnet Calculator — a free, browser-based tool for computing subnets, host ranges, and broadcast addresses in seconds. Enter any IP address and its subnet mask or prefix (dotted decimal or CIDR), and the tool instantly returns the network address, broadcast address, usable host range, and address totals — then split the network into smaller subnets and view a complete subnet table with every child network's range. Everything runs 100% in your browser: free, private, and offline.

How the Subnet Calculator Works

The tool accepts a mask as dotted decimal (e.g.255.255.255.0) or as a CIDR prefix (e.g. /24) and converts between them automatically. It then:

  1. 1. Computes the network address, broadcast address, and first/last usable host.
  2. 2. Shows the total addresses and usable host count, and flags private (RFC 1918) blocks.
  3. 3. Lets you split the block into smaller subnets (/25 through /32) and renders a full subnet table — network, broadcast, usable range, and host count for each child subnet, with one-click copy.

Example: Splitting a /24

Start with 192.168.1.0/24 and choose/28 from the split options. The tool borrows 4 host bits and returns16 subnets, each with 16 addresses and 14 usable hosts. The first subnet is 192.168.1.0/28 with usable hosts192.168.1.1 – 192.168.1.14; the second starts at192.168.1.16, and so on.

Who Uses This Tool

Network administrators planning VLANs and DHCP scopes,CCNA / Network+ students practising subnetting, cloud engineers sizing VPCs, and hobbyists setting up home labs all need fast, accurate subnet math. This tool delivers it with zero installation — just accurate results, offline, every time.

Frequently Asked Questions About Subnetting

What is a subnet mask?

A subnet mask is a 32-bit number that divides an IP address into the network part and the host part. Written in dotted decimal (like 255.255.255.0), it has 1-bits where the network lives and 0-bits where hosts live. The mask lets routers decide whether a destination is on the local network or must be reached through a gateway. A shorter mask (255.0.0.0, /8) means a huge network; a longer one (255.255.255.248, /29) means a tiny one.

What is the difference between a network address and a broadcast address?

The network address is the first address of a subnet — every host bit is 0. It identifies the subnet itself and is never assigned to a device. The broadcast address is the last address — every host bit is 1. Packets sent to the broadcast address reach every host on that subnet. For 192.168.1.0/24 the network address is 192.168.1.0 and the broadcast is 192.168.1.255.

How do I calculate the usable host range?

Count the host bits as 2^(32 − prefix). Subtract 2 for the network and broadcast addresses. For a /26 that is 2^6 = 64 addresses minus 2 = 62 usable hosts, running from network+1 to broadcast−1. So 203.0.113.64/26 has usable hosts 203.0.113.65 through 203.0.113.126. The two exceptions: /31 (both addresses usable, point-to-point) and /32 (a single address).

How many subnets does splitting a network create?

Splitting a network with prefix P into child subnets with prefix N creates 2^(N − P) subnets. For example, dividing a /24 into /28 subnets borrows 4 host bits: 2^4 = 16 subnets of 16 addresses each (14 usable). This tool lets you pick a child prefix and generates the complete subnet table — network, broadcast, and usable range for every child subnet.

What is a /30 and why is it used?

A /30 subnet has a 255.255.255.252 mask and contains exactly 4 addresses: network, 2 usable hosts, and broadcast. It is the classic size for a point-to-point link between two routers, since only two addresses are needed. Its 2 usable hosts make it the smallest subnet that still reserves a network and broadcast address.

What is the difference between classful and classless subnetting?

Classful subnetting (pre-1993) fixed networks to Class A (/8), Class B (/16), and Class C (/24) sizes. Classless routing (CIDR, RFC 1519) allows any prefix length — /23, /26, /30 — so address space is used far more efficiently. This tool uses classless math, so you can enter any prefix from /0 to /32.

Is this subnet calculator free and private?

Yes — completely free, no registration, and 100% private. All subnet math runs locally in your browser with plain JavaScript; your IP addresses are never sent to any server. The tool works offline after the page loads, making it perfect for field work without a connection.

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