CIDR /4 Subnet Reference

A massive IPv4 subnet with 268.435.456 total addresses and 268.435.454 usable host addresses.

Subnet Mask240.0.0.0
Wildcard Mask15.255.255.255
Total IPs268.435.456
Usable Hosts268.435.454
Mask (Hex)F0000000
Host Bits28

Binary Breakdown

Subnet Mask11110000.00000000.00000000.00000000
Wildcard Mask00001111.11111111.11111111.11111111

Network bits (1s): 4 ·  Host bits (0s): 28

Common Uses for /4

  • Large network segment
  • ISP/enterprise allocation

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Enter any IP address with /4 prefix to calculate exact network details.

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Frequently Asked Questions

What is the subnet mask for /4?

The subnet mask for /4 is 240.0.0.0 (hex: F0000000). In binary: 11110000.00000000.00000000.00000000.

How many hosts does a /4 subnet support?

A /4 subnet has 268.435.456 total addresses. Subtract 2 (network + broadcast) = 268.435.454 usable host addresses.

What is the wildcard mask for /4?

The wildcard mask (inverse mask) for /4 is 15.255.255.255. Used in Cisco ACLs and OSPF configurations to match the host portion of an address.

What is CIDR /4 used for?

Large network segment. ISP/enterprise allocation.

Complete CIDR Reference Table /0–/32

PrefixSubnet MaskWildcardTotal IPsUsable Hosts
/00.0.0.0255.255.255.2554.294.967.2964.294.967.294
/1128.0.0.0127.255.255.2552.147.483.6482.147.483.646
/2192.0.0.063.255.255.2551.073.741.8241.073.741.822
/3224.0.0.031.255.255.255536.870.912536.870.910
/4240.0.0.015.255.255.255268.435.456268.435.454
/5248.0.0.07.255.255.255134.217.728134.217.726
/6252.0.0.03.255.255.25567.108.86467.108.862
/7254.0.0.01.255.255.25533.554.43233.554.430
/8255.0.0.00.255.255.25516.777.21616.777.214
/9255.128.0.00.127.255.2558.388.6088.388.606
/10255.192.0.00.63.255.2554.194.3044.194.302
/11255.224.0.00.31.255.2552.097.1522.097.150
/12255.240.0.00.15.255.2551.048.5761.048.574
/13255.248.0.00.7.255.255524.288524.286
/14255.252.0.00.3.255.255262.144262.142
/15255.254.0.00.1.255.255131.072131.070
/16255.255.0.00.0.255.25565.53665.534
/17255.255.128.00.0.127.25532.76832.766
/18255.255.192.00.0.63.25516.38416.382
/19255.255.224.00.0.31.2558.1928.190
/20255.255.240.00.0.15.2554.0964.094
/21255.255.248.00.0.7.2552.0482.046
/22255.255.252.00.0.3.2551.0241.022
/23255.255.254.00.0.1.255512510
/24255.255.255.00.0.0.255256254
/25255.255.255.1280.0.0.127128126
/26255.255.255.1920.0.0.636462
/27255.255.255.2240.0.0.313230
/28255.255.255.2400.0.0.151614
/29255.255.255.2480.0.0.786
/30255.255.255.2520.0.0.342
/31255.255.255.2540.0.0.122
/32255.255.255.2550.0.0.011