240.0.0.0 Subnet Mask
240.0.0.0 is the subnet mask for a /4 network — 268,435,454 usable hosts out of 268,435,456 addresses.
CIDR Prefix
/4
Wildcard Mask
15.255.255.255
Total Addresses
268,435,456
Usable Hosts
268,435,454
Network Bits
4
Host Bits
28
240.0.0.0 in Binary
Each octet is eight bits. The highlighted bits are the 4 network bits; the rest are the 28 host bits that vary within the subnet.
240
0
0
0
Networks Using 240.0.0.0
| Network | Host Range | Broadcast |
|---|---|---|
| 0.0.0.0/4 | 0.0.0.1 – 15.255.255.254 | 15.255.255.255 |
| 160.0.0.0/4 | 160.0.0.1 – 175.255.255.254 | 175.255.255.255 |
| 192.0.0.0/4 | 192.0.0.1 – 207.255.255.254 | 207.255.255.255 |
Neighbouring Masks
Frequently Asked Questions
What CIDR prefix is 240.0.0.0?
240.0.0.0 is /4 in CIDR notation. The mask sets the first 4 of the 32 bits in an IPv4 address to 1, marking them as the network portion, and leaves the remaining 28 bits as 0 for hosts.
How many hosts does 240.0.0.0 allow?
A network with mask 240.0.0.0 holds 268,435,456 addresses, of which 268,435,454 are usable by hosts — the network address and the broadcast address are reserved.
What is the wildcard mask for 240.0.0.0?
The wildcard mask for 240.0.0.0 is 15.255.255.255. It is the bitwise inverse: every 1 in the subnet mask becomes a 0 and every 0 becomes a 1. Cisco access lists and OSPF network statements take the wildcard form rather than the subnet mask.
Standards
- RFC 950 — Internet Standard Subnetting Procedure
Defines the dotted-decimal subnet mask itself, and the rule that the network and broadcast addresses are not assignable to hosts.
- RFC 4632 — Classless Inter-Domain Routing (CIDR)
Establishes the /4 prefix notation that 240.0.0.0 is equivalent to, and requires masks to be contiguous — which is why exactly 33 of the 4.3 billion possible values are valid.