Introduction
An IP range calculator shows you every address inside a network block. Type in an IP address, a CIDR block like 192.168.1.0/24, a subnet mask, or a start and end IP. The tool then tells you the network address, the broadcast address, the first and last usable host, and how many addresses you get in total.
It works with both IPv4 and IPv6. You can enter the address in many ways: CIDR notation, a dotted mask like 255.255.255.0, a wildcard mask like 0.0.0.255, a dash range like 10.0.0.1-10.0.0.255, or just a plain IP on its own. If you only work with 32-bit addressing, the IPv4 Calculator covers the same ground with a narrower focus.
You also get extra details that help with real network work. The calculator shows the binary and hex forms of each address, the wildcard mask for access lists, the reverse DNS (PTR) name, and whether the IP is private, public, loopback, link-local, or multicast. A step-by-step section shows the math, so you can learn how subnetting works instead of just copying the answer.
This is useful if you plan subnets, set up a router, write firewall rules, or study for a networking exam like the CCNA. Quick-reference tables for Class A, Class B, and supernetting sit at the bottom of the page, and the row that matches your prefix is highlighted for you.
How to use our IP Range Calculator
Type an IP address, CIDR block, or IP range into the box. The calculator shows the network address, broadcast address, subnet mask, wildcard mask, first and last usable host, total addresses, and step-by-step math for IPv4 and IPv6.
IP Address / Range: Enter the address you want to check. You can use CIDR like 192.168.1.0/24, a subnet mask like 192.0.2.0/255.255.255.0, a wildcard mask like 192.0.2.0/0.0.0.255, a dash range like 10.0.0.1-10.0.0.255, or just a plain address like fe80::1. The badge under the box tells you which format was found.
Quick examples: Click any example button to fill the box for you. This is a fast way to see how each input format works.
Calculate: Click this button (or press Enter) to run the numbers. Results also update as you type.
Reset: Click this to clear your entry and go back to the default 192.168.1.10/24.
Copy buttons: Click the copy icon next to any result to copy that value, like the subnet mask or host range.
Quick-Reference Subnet Tables: Use the tabs at the bottom to view Class A, Class B, and supernetting charts. The row that matches your prefix is highlighted in green.
What Is an IP Range?
Every device on a network has an IP address. An IP range is just a group of IP addresses that sit next to each other, like house numbers on one street. Networks are built from these ranges, so routers know which addresses belong together and where to send data. If you want to inspect one single address rather than a whole block, the IP Address Calculator is the quicker route.
How IP Ranges Are Written
The most common way is CIDR notation, like 192.168.1.0/24. The number after the slash is the prefix length. It tells you how many bits at the front of the address are locked in for the network.1 The bits left over are used for hosts (devices).
- Small prefix (like /8) = big network, many addresses.
- Big prefix (like /30) = tiny network, few addresses.
- Each extra bit in the prefix cuts the size of the range in half.
You may also see the same range written with a subnet mask (255.255.255.0), a wildcard mask (0.0.0.255), or as a plain start-to-end range (10.0.0.1-10.0.0.255). They all describe the same idea in different styles.
Key Addresses in Every IPv4 Range
- Network address – the first address. It names the whole subnet and is not given to a device.2
- Broadcast address – the last address. Data sent here goes to every device in the subnet.2
- Usable hosts – everything in between. This is why usable hosts equal total addresses minus 2.2
Two special cases break that rule. A /31 gives 2 usable addresses for a point-to-point link (RFC 3021).4 A /32 is a single host.1
Common Subnet Sizes
| CIDR | Subnet Mask | Total Addresses | Usable Hosts |
|---|---|---|---|
| /30 | 255.255.255.252 | 4 | 2 |
| /29 | 255.255.255.248 | 8 | 6 |
| /28 | 255.255.255.240 | 16 | 14 |
| /24 | 255.255.255.0 | 256 | 254 |
| /16 | 255.255.0.0 | 65,536 | 65,534 |
| /8 | 255.0.0.0 | 16,777,216 | 16,777,214 |
Private, Public, and Special Ranges
Some ranges are set aside for use inside homes and offices. These private ranges are 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16.3 They are not routed on the open internet.3 A router usually uses NAT to share one public address. Other blocks have jobs of their own, such as 127.0.0.0/8 for loopback and 169.254.0.0/16 for link-local (APIPA) addresses.6 Multicast uses 224.0.0.0 to 239.255.255.255.16
IPv6 Ranges
IPv6 addresses are 128 bits long instead of 32, so the ranges are huge.7 A single /64 holds about 18 quintillion addresses. That is the normal size for one network segment.9 IPv6 has no broadcast addresses; multicast does that job.8 The global unicast addresses handed out today come from 2000::/3.10 Unique local addresses, for use inside a site, start with fc00::/7.11 Link-local addresses start with fe80::/10.8
Why IP Ranges Matter
Network admins use IP ranges to split one big network into smaller subnets. Smaller subnets cut down on broadcast traffic, keep departments apart, and make firewall rules simpler. Wildcard masks are used in access control lists on Cisco gear.5 Cloud networks use CIDR blocks too: when you create an AWS VPC, you must specify an IPv4 CIDR block between a /16 netmask and a /28 netmask.17 DHCP scope planning works in CIDR blocks as well. Picking the right prefix length means you have enough addresses for your devices without wasting a big block.