By Madan Kc, ISP/GPON engineer at DG Link Network · Updated 13 November 2026
192.168.10.37/26) or with a mask (192.168.10.37 255.255.255.192). The tool shows the network, broadcast, usable host range and host count, and can split the block into smaller subnets for customer pools.Subnet calculator
How many hosts do I need?
How the numbers are worked out
A prefix such as /26 means the first 26 bits are the network part and the remaining 6 bits are for hosts. The block holds 26 = 64 addresses. The first is the network address and the last is the broadcast address, so 62 are usable for hosts. A /31 has no network or broadcast address and gives 2 usable addresses on point-to-point links (RFC 3021). A /32 is a single host.
| Prefix | Mask | Addresses | Usable hosts | Typical use |
|---|---|---|---|---|
| /30 | 255.255.255.252 | 4 | 2 | Router-to-router link |
| /29 | 255.255.255.248 | 8 | 6 | Small business public block |
| /28 | 255.255.255.240 | 16 | 14 | Small public block |
| /26 | 255.255.255.192 | 64 | 62 | Small PON or POP pool |
| /24 | 255.255.255.0 | 256 | 254 | Customer pool, one VLAN |
| /22 | 255.255.252.0 | 1,024 | 1,022 | Large PPPoE pool |
For PPPoE customers, size the pool for the number of simultaneous sessions, not the number of subscribers. See the MikroTik PPPoE server guide for how a pool is used.
FAQ
What is the difference between /24 and 255.255.255.0?
They mean the same thing. /24 is CIDR notation and 255.255.255.0 is the dotted mask. Both say that the first 24 bits are the network.
Why are two addresses lost in every subnet?
The first address names the network and the last is the broadcast address, so neither can be given to a host. /31 and /32 are the exceptions.
Does this tool support IPv6?
No. It handles IPv4 only.
Is my input sent anywhere?
No. The calculation runs in your browser and nothing is uploaded.
Related
Sources and testing: Standard IPv4 subnetting rules and RFC 3021 for /31 links. Results are planning aids; check them against your router before applying.