IPRangeExplorer

10.0.0.0/16

Private (RFC 1918) RFC 1918

The 10.0.0.0/16 block offers 65,536 IP addresses and is one of the most common starting points for AWS VPC, Azure VNet, and on-premises subnetting schemes. It can be split into 256 /24 subnets.

Network Address
10.0.0.0
Broadcast Address
10.0.255.255
Subnet Mask
255.255.0.0
Usable Hosts
65,534
First Usable IP
10.0.0.1
Last Usable IP
10.0.255.254
Total IPs
65,536
Prefix Length
/16

Network address — the base address of the block (10.0.0.0). All devices in this subnet share this prefix. Cannot be assigned to a host.

Broadcast address — packets sent to 10.0.255.255 are delivered to every device in the subnet. Also reserved — not assignable.

Usable hosts — the 65,534 addresses between those two that you can assign to servers, VMs, or interfaces.

Subnet mask — 255.255.0.0 is the dotted-decimal equivalent of /16. Older tools and Cisco configs use this format instead of CIDR slash notation.

Full Details

CIDR Notation 10.0.0.0/16
Network Address 10.0.0.0
Broadcast Address 10.0.255.255
Subnet Mask 255.255.0.0
Wildcard Mask 0.0.255.255
Prefix Length /16
IP Address Class Class A
Total IP Addresses 65,536
Usable Host Addresses 65,534
First Usable IP 10.0.0.1
Last Usable IP 10.0.255.254
Network (Hex) 0x0A000000
Broadcast (Hex) 0x0A00FFFF
Governing RFC RFC 1918
Address Type Private (RFC 1918)

Binary Representation

Network Address
00001010.00000000 00001010.00000000.00000000.00000000
Subnet Mask
11111111.11111111.00000000.00000000

The first 16 bits (1s in the mask) identify the network. The remaining 16 bits identify hosts within the network.

Split into Equal Subnets

Split 10.0.0.0/16 into 2 equal /17 subnets (32,766 usable hosts each).

# CIDR Network First Usable Last Usable Broadcast Hosts
1 10.0.0.0/17 10.0.0.0 10.0.0.1 10.0.127.254 10.0.127.255 32,766
2 10.0.128.0/17 10.0.128.0 10.0.128.1 10.0.255.254 10.0.255.255 32,766

Common Use Cases

  • → AWS VPC CIDR (common starting point)
  • → Single-region cloud network with multiple subnets
  • → Medium enterprise campus networks

Code Examples

Terraform 
# Terraform — AWS VPC with public + private subnets
resource "aws_vpc" "main" {
  cidr_block = "10.0.0.0/16"
  tags       = { Name = "main" }
}

resource "aws_subnet" "public" {
  vpc_id            = aws_vpc.main.id
  cidr_block        = "10.0.0.0/24"
  availability_zone = "us-east-1a"
  map_public_ip_on_launch = true
  tags = { Name = "public-us-east-1a" }
}

resource "aws_subnet" "private" {
  vpc_id            = aws_vpc.main.id
  cidr_block        = "10.0.1.0/24"
  availability_zone = "us-east-1a"
  tags = { Name = "private-us-east-1a" }
}
AWS CLI 
# AWS CLI — create VPC and subnets
VPC_ID=$(aws ec2 create-vpc --cidr-block 10.0.0.0/16 \
  --query Vpc.VpcId --output text)

aws ec2 create-subnet \
  --vpc-id $VPC_ID \
  --cidr-block 10.0.0.0/24 \
  --availability-zone us-east-1a

aws ec2 create-subnet \
  --vpc-id $VPC_ID \
  --cidr-block 10.0.1.0/24 \
  --availability-zone us-east-1b

/16 Subnet Reference

Total IPs 65,536
Usable Hosts 65,534
Subnet Mask 255.255.0.0
Wildcard 0.0.255.255
Full /16 reference →

Related Ranges

Parent /15 block 10.0.0.0/15 Sibling /16 block 10.1.0.0/16

Adjacent Prefix Sizes

/14 262,142 hosts /15 131,070 hosts /16 65,534 hosts /17 32,766 hosts /18 16,382 hosts

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