100.86.128.0/18

Public

Class A — /18 prefix — 16,382 usable hosts

Network Address

100.86.128.0

Broadcast Address

100.86.191.255

Subnet Mask

255.255.192.0

Usable Hosts

16,382

First Usable IP

100.86.128.1

Last Usable IP

100.86.191.254

Total IPs

16,384

Prefix Length

/18

Network address — the base address of the block (100.86.128.0). All devices in this subnet share this prefix. Cannot be assigned to a host.

Broadcast address — packets sent to 100.86.191.255 are delivered to every device in the subnet. Also reserved — not assignable.

Usable hosts — the 16,382 addresses between those two that you can assign to servers, VMs, or interfaces.

Subnet mask — 255.255.192.0 is the dotted-decimal equivalent of /18. Older tools and Cisco configs use this format instead of CIDR slash notation.

Full Details

CIDR Notation	100.86.128.0/18
Network Address	100.86.128.0
Broadcast Address	100.86.191.255
Subnet Mask	255.255.192.0
Wildcard Mask	0.0.63.255
Prefix Length	/18
IP Address Class	Class A
Total IP Addresses	16,384
Usable Host Addresses	16,382
First Usable IP	100.86.128.1
Last Usable IP	100.86.191.254
Network (Hex)	0x64568000
Broadcast (Hex)	0x6456BFFF
Address Type	Public / Globally Routable

Binary Representation

Network Address

01100100.01010110 01100100.01010110.10000000.00000000

Subnet Mask

11111111.11111111.11000000.00000000

The first 18 bits (1s in the mask) identify the network. The remaining 14 bits identify hosts within the network.

Split into Equal Subnets

Split 100.86.128.0/18 into 2 equal /19 subnets (8,190 usable hosts each).

#	CIDR	Network	First Usable	Last Usable	Broadcast	Hosts
1	100.86.128.0/19	100.86.128.0	100.86.128.1	100.86.159.254	100.86.159.255	8,190
2	100.86.160.0/19	100.86.160.0	100.86.160.1	100.86.191.254	100.86.191.255	8,190

Split 100.86.128.0/18 into 4 equal /20 subnets (4,094 usable hosts each).

#	CIDR	Network	First Usable	Last Usable	Broadcast	Hosts
1	100.86.128.0/20	100.86.128.0	100.86.128.1	100.86.143.254	100.86.143.255	4,094
2	100.86.144.0/20	100.86.144.0	100.86.144.1	100.86.159.254	100.86.159.255	4,094
3	100.86.160.0/20	100.86.160.0	100.86.160.1	100.86.175.254	100.86.175.255	4,094
4	100.86.176.0/20	100.86.176.0	100.86.176.1	100.86.191.254	100.86.191.255	4,094

Split 100.86.128.0/18 into 8 equal /21 subnets (2,046 usable hosts each).

#	CIDR	Network	First Usable	Last Usable	Broadcast	Hosts
1	100.86.128.0/21	100.86.128.0	100.86.128.1	100.86.135.254	100.86.135.255	2,046
2	100.86.136.0/21	100.86.136.0	100.86.136.1	100.86.143.254	100.86.143.255	2,046
3	100.86.144.0/21	100.86.144.0	100.86.144.1	100.86.151.254	100.86.151.255	2,046
4	100.86.152.0/21	100.86.152.0	100.86.152.1	100.86.159.254	100.86.159.255	2,046
5	100.86.160.0/21	100.86.160.0	100.86.160.1	100.86.167.254	100.86.167.255	2,046
6	100.86.168.0/21	100.86.168.0	100.86.168.1	100.86.175.254	100.86.175.255	2,046
7	100.86.176.0/21	100.86.176.0	100.86.176.1	100.86.183.254	100.86.183.255	2,046
8	100.86.184.0/21	100.86.184.0	100.86.184.1	100.86.191.254	100.86.191.255	2,046

Split 100.86.128.0/18 into 16 equal /22 subnets (1,022 usable hosts each).

#	CIDR	Network	First Usable	Last Usable	Broadcast	Hosts
1	100.86.128.0/22	100.86.128.0	100.86.128.1	100.86.131.254	100.86.131.255	1,022
2	100.86.132.0/22	100.86.132.0	100.86.132.1	100.86.135.254	100.86.135.255	1,022
3	100.86.136.0/22	100.86.136.0	100.86.136.1	100.86.139.254	100.86.139.255	1,022
4	100.86.140.0/22	100.86.140.0	100.86.140.1	100.86.143.254	100.86.143.255	1,022
5	100.86.144.0/22	100.86.144.0	100.86.144.1	100.86.147.254	100.86.147.255	1,022
6	100.86.148.0/22	100.86.148.0	100.86.148.1	100.86.151.254	100.86.151.255	1,022
7	100.86.152.0/22	100.86.152.0	100.86.152.1	100.86.155.254	100.86.155.255	1,022
8	100.86.156.0/22	100.86.156.0	100.86.156.1	100.86.159.254	100.86.159.255	1,022
9	100.86.160.0/22	100.86.160.0	100.86.160.1	100.86.163.254	100.86.163.255	1,022
10	100.86.164.0/22	100.86.164.0	100.86.164.1	100.86.167.254	100.86.167.255	1,022
11	100.86.168.0/22	100.86.168.0	100.86.168.1	100.86.171.254	100.86.171.255	1,022
12	100.86.172.0/22	100.86.172.0	100.86.172.1	100.86.175.254	100.86.175.255	1,022
13	100.86.176.0/22	100.86.176.0	100.86.176.1	100.86.179.254	100.86.179.255	1,022
14	100.86.180.0/22	100.86.180.0	100.86.180.1	100.86.183.254	100.86.183.255	1,022
15	100.86.184.0/22	100.86.184.0	100.86.184.1	100.86.187.254	100.86.187.255	1,022
16	100.86.188.0/22	100.86.188.0	100.86.188.1	100.86.191.254	100.86.191.255	1,022

/18 Subnet Reference

Total IPs 16,384

Usable Hosts 16,382

Subnet Mask 255.255.192.0

Wildcard 0.0.63.255

Full /18 reference →

Related Ranges

Parent /17 block 100.86.128.0/17 Sibling /18 block 100.86.192.0/18

Adjacent Prefix Sizes

/16 65,534 hosts /17 32,766 hosts /18 16,382 hosts /19 8,190 hosts /20 4,094 hosts