IPRangeExplorer

10.81.232.0/21

Private (RFC 1918) RFC 1918

Class A — /21 prefix — 2,046 usable hosts

Network Address
10.81.232.0
Broadcast Address
10.81.239.255
Subnet Mask
255.255.248.0
Usable Hosts
2,046
First Usable IP
10.81.232.1
Last Usable IP
10.81.239.254
Total IPs
2,048
Prefix Length
/21

Network address — the base address of the block (10.81.232.0). All devices in this subnet share this prefix. Cannot be assigned to a host.

Broadcast address — packets sent to 10.81.239.255 are delivered to every device in the subnet. Also reserved — not assignable.

Usable hosts — the 2,046 addresses between those two that you can assign to servers, VMs, or interfaces.

Subnet mask — 255.255.248.0 is the dotted-decimal equivalent of /21. Older tools and Cisco configs use this format instead of CIDR slash notation.

Full Details

CIDR Notation 10.81.232.0/21
Network Address 10.81.232.0
Broadcast Address 10.81.239.255
Subnet Mask 255.255.248.0
Wildcard Mask 0.0.7.255
Prefix Length /21
IP Address Class Class A
Total IP Addresses 2,048
Usable Host Addresses 2,046
First Usable IP 10.81.232.1
Last Usable IP 10.81.239.254
Network (Hex) 0x0A51E800
Broadcast (Hex) 0x0A51EFFF
Governing RFC RFC 1918
Address Type Private (RFC 1918)

Binary Representation

Network Address
00001010.01010001 00001010.01010001.11101000.00000000
Subnet Mask
11111111.11111111.11111000.00000000

The first 21 bits (1s in the mask) identify the network. The remaining 11 bits identify hosts within the network.

Split into Equal Subnets

Split 10.81.232.0/21 into 2 equal /22 subnets (1,022 usable hosts each).

# CIDR Network First Usable Last Usable Broadcast Hosts
1 10.81.232.0/22 10.81.232.0 10.81.232.1 10.81.235.254 10.81.235.255 1,022
2 10.81.236.0/22 10.81.236.0 10.81.236.1 10.81.239.254 10.81.239.255 1,022

/21 Subnet Reference

Total IPs 2,048
Usable Hosts 2,046
Subnet Mask 255.255.248.0
Wildcard 0.0.7.255
Full /21 reference →

Related Ranges

Parent /20 block 10.81.224.0/20 Sibling /21 block 10.81.224.0/21

Adjacent Prefix Sizes

/19 8,190 hosts /20 4,094 hosts /21 2,046 hosts /22 1,022 hosts /23 510 hosts

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