Subnet for 10000 hosts
A network that needs 10000 hosts fits in a /18, mask 255.255.192.0, with 16,382 usable addresses.
A network built for 10000 hosts needs a /18. The mask is 255.255.192.0, and its 16,382 usable addresses leave 6,382 spare for growth.
The next smaller block, a /19, only allows 8,190 usable addresses, which is not enough for 10000 hosts. That makes /18 the smallest block that fits.
Enter any address below to see the exact network, broadcast, and host range for a /18 block.
Calculate a /18 network
Accepts CIDR (192.0.2.0/24), IP + mask (192.0.2.0 255.255.255.0), or a bare IP (defaults to /24).
11000000.00000000.00000010.0000000011111111.11111111.11000000.00000000Example: 192.0.2.0/18
Taking 192.0.2.0/18 as a worked example, a /18 block breaks down like this:
| Network address | 192.0.0.0 |
|---|---|
| Usable range | 192.0.0.1 - 192.0.63.254 |
| Broadcast address | 192.0.63.255 |
| Total addresses | 16,384 |
| Usable hosts | 16,382 |
Frequently asked questions
What subnet mask do I need for 10000 hosts?
A network with 10000 hosts fits in a /18, which uses the mask 255.255.192.0 and provides 16,382 usable addresses.
How many addresses does a /18 block have in total?
A /18 has 16,384 total addresses, 16,382 of them usable (the total minus the network and broadcast addresses, except for /31 and /32).
Does a /18 waste any addresses for 10000 hosts?
Yes, 6,382 addresses of headroom. A /18 provides 16,382 usable addresses for the 10000 you need, and the next smaller block, a /19, does not hold enough.
How do I work this out myself?
Find the smallest power of two, minus two, that is at least 10000. That takes 14 host bits, which leaves a /18 prefix. See how to calculate a subnet mask for the full method.