# /22 Subnet Mask (255.255.252.0) – Hosts, Range & FAQ

> The /22 subnet mask is 255.255.252.0. A /22 block holds 1,024 addresses with 1,022 usable hosts — ranges, wildcard, binary math and FAQs.

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# /22 Subnet Mask ReferenceIPv4

Four /24s, 1,022 usable hosts, mask 255.255.252.0: the /22 is arguably the best compromise between a cramped /24 and a sprawling /20. It is also the size registries have treated as the floor for fresh ISP allocations during the IPv4-scarcity era.

The /22 subnet mask is 255.255.252.0, equivalent to 0.0.3.255 as a wildcard. A /22 block contains 1,024 IP addresses (1,022 usable hosts).

## /22 facts at a glance

- **Subnet mask:** 255.255.252.0
- **Wildcard mask:** 0.0.3.255
- **Binary mask:** 11111111.11111111.11111100.00000000
- **Total addresses:** 1,024
- **Usable hosts:** 1,022 (excludes network & broadcast)
- **Block size:** 1,024 addresses (210)
- **Typical role:** Mid-size networks and ISP allocations

## Example /22 networks

Three consecutive /22 blocks, starting at the /22 boundary that contains 198.51.100.0:

| Network | Usable range | Usable hosts |
| --- | --- | --- |
| 198.51.100.0/22 | 198.51.100.1 – 198.51.103.254 | 1,022 |
| 198.51.104.0/22 | 198.51.104.1 – 198.51.107.254 | 1,022 |
| 198.51.108.0/22 | 198.51.108.1 – 198.51.111.254 | 1,022 |

## How to calculate a /22 mask

A /22 mask sets the first 22 bits of a 32-bit number to 1 and leaves the remaining 10 bits as 0. In binary that reads `11111111.11111111.11111100.00000000`, which converts to dotted decimal `255.255.252.0`. Each block covers a contiguous run of 210 = 1,024 addresses, and every block starts at a multiple of that size. The wildcard simply flips every bit, giving `0.0.3.255`.

## Where /22 is used

- Mid-size branches or factories that want four VLAN-sized /24s under one allocation.
- Efficient cloud VPC sizing when a /16 would sit mostly idle.
- Public address blocks leased to customers who need more than one /24.

Alignment: the third octet advances in steps of four, so 10.1.4.0/22 spans 10.1.4.0 through 10.1.7.255.

Cloud-friendly: AWS accepts subnets from /16 down to /28, and a /22 stays comfortably inside every provider's bounds while wasting far less than a /16.

## Frequently asked questions

**How many usable hosts are in a /22?**

1,022 of 1,024 total addresses.

**What is the subnet mask for a /22?**

255.255.252.0, wildcard 0.0.3.255.

**How many /24s are in a /22?**

Four consecutive ones: for example, 10.1.4.0/22 holds the four /24 networks 10.1.4.0, 10.1.5.0, 10.1.6.0, and 10.1.7.0.

**Why pick a /22 instead of a /24?**

Headroom without extravagance: four LAN-sized segments under one summary line, with none of the idle sprawl of a /20 or /16.

## Open this block in a calculator

[Open the /22 block in the subnet calculator](https://itinsighthub.com/subnet-calculator/?q=198.51.100.0%2F22)

[Get the /22 wildcard mask →](https://itinsighthub.com/wildcard-mask-calculator/?q=%2F22)

### Related prefixes

[/21](https://itinsighthub.com/subnet/21/)[/23](https://itinsighthub.com/subnet/23/)[/24](https://itinsighthub.com/subnet/24/)[/26](https://itinsighthub.com/subnet/26/)[/28](https://itinsighthub.com/subnet/28/)[/30](https://itinsighthub.com/subnet/30/)

← /21 subnet mask
/23 subnet mask →

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