CIDR /3 Subnet Reference

A massive IPv4 subnet with 536.870.912 total addresses and 536.870.910 usable host addresses.

Subnet Mask224.0.0.0
Wildcard Mask31.255.255.255
Total IPs536.870.912
Usable Hosts536.870.910
Mask (Hex)E0000000
Host Bits29

Binary Breakdown

Subnet Mask11100000.00000000.00000000.00000000
Wildcard Mask00011111.11111111.11111111.11111111

Network bits (1s): 3 ·  Host bits (0s): 29

Common Uses for /3

  • Large network segment
  • ISP/enterprise allocation

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Enter any IP address with /3 prefix to calculate exact network details.

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Frequently Asked Questions

What is the subnet mask for /3?

The subnet mask for /3 is 224.0.0.0 (hex: E0000000). In binary: 11100000.00000000.00000000.00000000.

How many hosts does a /3 subnet support?

A /3 subnet has 536.870.912 total addresses. Subtract 2 (network + broadcast) = 536.870.910 usable host addresses.

What is the wildcard mask for /3?

The wildcard mask (inverse mask) for /3 is 31.255.255.255. Used in Cisco ACLs and OSPF configurations to match the host portion of an address.

What is CIDR /3 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