/5 subnet: mask 248.0.0.0, 134,217,728 addresses

Everything about a /5 network, with the CIDR calculator pre-filled — change the IP to calculate your own block.

Enter a CIDR range above to calculate

Is an IP inside a CIDR block?

Yes — 10.0.42.7 is inside 10.0.0.0/16.

Do two CIDR blocks overlap?

Overlap — 10.0.128.0/20 sits inside 10.0.0.0/16 (10.0.128.0 – 10.0.143.255).

CIDR blocks never partly overlap: one is inside the other, or they don't touch at all. Overlapping VPCs can't be peered.

/5 at a glance

Subnet mask
248.0.0.0
Wildcard mask
7.255.255.255
Mask in binary
11111000.00000000.00000000.00000000
Host bits
27
Total addresses
134,217,728
Usable hosts
134,217,726 (network and broadcast address excluded)
Equivalent /24 networks
524,288

Splitting a /5 into smaller subnets

  • 2 × /6 — 67,108,864 addresses each (67,108,862 usable)
  • 4 × /7 — 33,554,432 addresses each (33,554,430 usable)
  • 8 × /8 — 16,777,216 addresses each (16,777,214 usable)
  • 16 × /9 — 8,388,608 addresses each (8,388,606 usable)

Frequently asked

What is the subnet mask for /5?

248.0.0.0. The first 5 bits are network bits and the remaining 27 are host bits; the wildcard (inverse) mask is 7.255.255.255.

How many IP addresses are in a /5?

134,217,728 in total. 134,217,726 of them can be assigned to hosts, because the first is the network address and the last is the broadcast address.

CIDR to subnet mask cheat sheet

CIDRSubnet maskAddressesUsable hosts
/8255.0.0.016,777,21616,777,214
/12255.240.0.01,048,5761,048,574
/16255.255.0.065,53665,534
/17255.255.128.032,76832,766
/18255.255.192.016,38416,382
/19255.255.224.08,1928,190
/20255.255.240.04,0964,094
/21255.255.248.02,0482,046
/22255.255.252.01,0241,022
/23255.255.254.0512510
/24255.255.255.0256254
/25255.255.255.128128126
/26255.255.255.1926462
/27255.255.255.2243230
/28255.255.255.2401614
/29255.255.255.24886
/30255.255.255.25242
/31255.255.255.25422
/32255.255.255.25511
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