Subnet Mask to Wildcard & CIDR

Subnet Mask to Wildcard & CIDR Slash Notation

Convert dotted-decimal subnet masks (255.255.255.0) into Cisco wildcard masks (0.0.0.255), CIDR prefixes (/24), and Hex representations. Inspect 32-bit architecture, usable host pools, and ready-to-deploy Cisco IOS/Linux configuration snippets in real-time.

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Presets:

Input Mask, Prefix or Wildcard

Quick CIDR Prefix Scrubbing:/24254 Usable Hosts
/0 (Internet)/16 (Class B)/24 (Class C)/30 (P2P)/32 (Host)
Subnet Mask (Dotted-Decimal)
255.255.255.0
Hex: 0xFFFFFF00
Cisco Wildcard Mask
0.0.0.255
Inverse: 255.255.255.255 - Mask
CIDR Slash Notation
/24
24 Leading Network 1-bits
Usable IPv4 Host Pool
254
Total: 256 IPs

32-Bit Binary & Octet Architecture

Network Bits (1s: 24)Host Bits (0s: 8)
Octet #1255
1286432168421
Subnet Mask
11111111
Wildcard Mask0
00000000
Octet #2255
1286432168421
Subnet Mask
11111111
Wildcard Mask0
00000000
Octet #3255
1286432168421
Subnet Mask
11111111
Wildcard Mask0
00000000
Octet #40
1286432168421
Subnet Mask
00000000
Wildcard Mask255
11111111
Subnet Mask:11111111.11111111.11111111.00000000

Subnet Range & IP Scope (Calculated for 192.168.1.1)

Class CRFC 1918 Private (192.168.0.0/16)
Network ID Address192.168.1.0Subnet base identifier
Directed Broadcast192.168.1.255Subnet broadcast address
First Usable Host192.168.1.1Typically default gateway
Last Usable Host192.168.1.254End of DHCP lease pool

Ready-to-Deploy Cisco IOS & OS Configuration Snippets

Cisco Standard & Extended ACL
access-list 10 permit 192.168.1.0 0.0.0.255
access-list 101 permit ip 192.168.1.0 0.0.0.255 any
Cisco OSPF & EIGRP Routing
router ospf 1
 network 192.168.1.0 0.0.0.255 area 0
router eigrp 100
 network 192.168.1.0 0.0.0.255
Cisco IOS & ASA Firewall Interface
interface GigabitEthernet0/1
 ip address 192.168.1.1 255.255.255.0
 no shutdown

# Cisco ASA / Firepower Object
object network OBJ-NET
 subnet 192.168.1.0 255.255.255.0
Linux, Windows & MikroTik
# Linux iproute2
sudo ip addr add 192.168.1.1/24 dev eth0

# Windows PowerShell
New-NetIPAddress -IPAddress 192.168.1.1 -PrefixLength 24 -InterfaceAlias "Ethernet"

# MikroTik RouterOS
/ip address add address=192.168.1.1/24 interface=ether1