IP Subnet Calculator
Instant IPv4 subnet calculations, determine total number of IPs, how an IPv4 block breaks down into smaller subnets, and more.
Calculating CIDR and determining the correct subnets within a /16 or /19 can be challenging and error-prone when done manually. The process is time-consuming and tedious, with plenty of room for mistakes.
We’ve simplified this with our instant networking subnet calculator. It effortlessly calculates the total number of IPs, shows how an IP block divides into smaller subnets, fixes mistaken subnets and more. If you want to check blacklisted IPs, we can help.
How to use our IP Subnet Calculator:
- Input your IPv4 Address Block in the top left field of the table.
- Change one of the following fields to breakdown your IPv4 block. (the other fields will update based on your selection)
- Subnet Mask
- Total IPv4 Addresses
- Number of Subnets
- Let our calculator do the match for you. It will provide the correct breakdown into smaller subnets based on your criteria.
- Scroll down to see all results. For a /16, you can expect to see 256 Subnet ID’s.
Calculate the Average Price of an IP Subnet
If you have any unused IP addresses, they can bring in some serious revenue. We created a useful subnet calculator based on the subnet sizes and agverage pricing data from this calendar year. Just choose your subnet, and let us calculate the potential value of your unused IPs address assets.
What is an IPv4 Subnet?
A subnet is a division of an IP network, a set of protocols used on the Internet and similar networks. Known as TCP/IP, subnetting involves dividing a network into multiple subnetworks, with routers facilitating traffic exchange and acting as physical boundaries. While IPv4 remains prevalent, IPv6 usage has surged since 2006.
An IP address includes a network number (routing prefix) and a rest field (host identifier). The routing prefix is usually expressed in CIDR notation for both IPv4 and IPv6. CIDR creates unique identifiers for networks and devices. An ASN (autonomous system number) is a distinct identifier allocated to a network or group of IP prefixes managed by one or more network operators. CGNAT (Network Address Translation) hides the IP address from the external network by mapping a private IPv4 address to a single public IP address.
In IPv4, subnet masks, often shown in dot-decimal notation, distinguish the network number from the host identifier. IPv6 uses the network prefix similarly, with prefix length indicating the number of address bits.
Before CIDR, IPv4 network prefixes were derived from the IP address class (A, B, or C) and network mask. Now, IP address assignment requires both an address and its network mask, reflecting modern advancements in network architecture.
IPv4 Classes, Block Sizes & Total Number of IPs
Class A
Class A subnets, known as a /8, consist of the 256 Ipv4 blocks in the first octet. Example: 79.xxx.xxx.0/8
| IPv4 Block Size | Total # of IP’s |
|---|---|
| /8 | 16,777,216 |
| /9 | 8,388,608 |
| /10 | 4,194,304 |
| /11 | 2,097,152 |
| /12 | 1,048,576 |
| /13 | 524,288 |
| /14 | 262,144 |
| /15 | 131,072 |
Class B
A Class B subnet, or /16, consists of the 256 Ipv4 blocks in the second octet. Example: xxx.79.xxx.0/16
| IPv4 Block Size | Total # of IP’s |
|---|---|
| /16 | 65,536 |
| /17 | 32,768 |
| /18 | 16,384 |
| /19 | 8,192 |
| /20 | 4,096 |
| /21 | 2,046 |
| /22 | 1,022 |
| /23 | 510 |
Class C
A Class C subnet, commonly referred to as a /24, consist of the 256 Ipv4 blocks in the third octet. Example: xxx.xxx.79.0/16
| IPv4 Block Size | Total # of IP’s |
|---|---|
| /24 | 256 |
| /25 | 128 |
| /26 | 64 |
| /27 | 32 |
| /28 | 16 |
| /29 | 8 |
| /30 | 4 |
| /31 | 2 |
Thinking about Buying or Selling IPs? Visit our Marketplace
66.xxx.xxx.x/23
new
| TOTAL IPs | PRICE/IP | PRICE |
| 8,192 | $XX,XX | $XX,XXX |
Status: Available
203.x.xx.x/22
new
| TOTAL IPs | PRICE/IP | PRICE |
| 1,024 | $XX,XX | $XX,XXX |
Status: Available
146.xxxxx.x/19
new
| TOTAL IPs | PRICE/IP | PRICE |
| 8,192 | $XX,XX | $XX,XXX |
Status: Available