IPRangeExplorer

21.70.0.0/16

Public

Class A — /16 prefix — 65,534 usable hosts

Network Address
21.70.0.0
Broadcast Address
21.70.255.255
Subnet Mask
255.255.0.0
Usable Hosts
65,534
First Usable IP
21.70.0.1
Last Usable IP
21.70.255.254
Total IPs
65,536
Prefix Length
/16

Network address — the base address of the block (21.70.0.0). All devices in this subnet share this prefix. Cannot be assigned to a host.

Broadcast address — packets sent to 21.70.255.255 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 21.70.0.0/16
Network Address 21.70.0.0
Broadcast Address 21.70.255.255
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 21.70.0.1
Last Usable IP 21.70.255.254
Network (Hex) 0x15460000
Broadcast (Hex) 0x1546FFFF
Address Type Public / Globally Routable

Binary Representation

Network Address
00010101.01000110 00010101.01000110.00000000.00000000
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 21.70.0.0/16 into 2 equal /17 subnets (32,766 usable hosts each).

# CIDR Network First Usable Last Usable Broadcast Hosts
1 21.70.0.0/17 21.70.0.0 21.70.0.1 21.70.127.254 21.70.127.255 32,766
2 21.70.128.0/17 21.70.128.0 21.70.128.1 21.70.255.254 21.70.255.255 32,766

/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 21.70.0.0/15 Sibling /16 block 21.71.0.0/16

Adjacent Prefix Sizes

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

Calculate Another