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IP subnet / CIDR calculator
IPv4 subnet / CIDR calculator: network, broadcast, mask, wildcard, host range and number of usable hosts. Made for network techs and MikroTik.
Subnet mask table /8 to /32
| CIDR | Mask | Usable hosts |
|---|
Subnet calculator for network techs
This IPv4 subnet / CIDR calculator instantly gives you the network address, broadcast, mask, wildcard, first and last host and the number of usable hosts. Type the IP with its prefix (for example 192.168.88.1/24) or with the mask (10.0.0.5 255.255.255.0). It's handy for DHCP pools, routes, MikroTik firewall rules and splitting customer networks.
Frequently asked questions
What does /24 mean?
It's CIDR notation: it says how many bits of the address are the network part. /24 equals the mask 255.255.255.0, with 254 usable hosts.
Why does a /30 have only 2 hosts?
Every subnet reserves the network and broadcast addresses. A /30 has 4 addresses, leaving 2 for devices, ideal for point-to-point links. /31 subnets (RFC 3021) use both addresses on point-to-point links.
What is the wildcard for?
It's the inverted mask (for example 0.0.0.255 for a /24) and is used in Cisco access lists and OSPF.
Which networks are private?
The RFC 1918 ones: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. 100.64.0.0/10 is CGNAT, used by internet providers.
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