Subnet Calculator
Enter an IP address with a CIDR prefix or subnet mask to get the network, broadcast, host range, masks and binary breakdown, and split it into smaller subnets.
- CIDR or subnet mask
- Host range & broadcast
- Binary view
- Split into subnets
Also accepts a mask: 10.0.0.5 255.255.252.0
192.168.1.0/24
- Network address
- 192.168.1.0
- Broadcast address
- 192.168.1.255
- Usable host range
- 192.168.1.1 – 192.168.1.254
- Usable hosts
- 254
- Total addresses
- 256
- Subnet mask
- 255.255.255.0
- Wildcard mask
- 0.0.0.255
- CIDR notation
- /24
- IP class
- C
- Address type
- Private (RFC 1918)
- Reverse DNS zone
- 1.168.192.in-addr.arpa
- IPv4-mapped IPv6
- ::ffff:192.168.1.10
- Integer / hex
- 3232235786 · 0xC0A8010A
Binary
- IP
- 11000000.10101000.00000001.00001010
- Mask
- 11111111.11111111.11111111.00000000
- Network
- 11000000.10101000.00000001.00000000
- Broadcast
- 11000000.10101000.00000001.11111111
Network bits are highlighted; the rest are host bits.
4 subnets of 64 addresses (62 usable each).
| Network | Usable range | Broadcast |
|---|---|---|
| 192.168.1.0/26 | 192.168.1.1 – 192.168.1.62 | 192.168.1.63 |
| 192.168.1.64/26 | 192.168.1.65 – 192.168.1.126 | 192.168.1.127 |
| 192.168.1.128/26 | 192.168.1.129 – 192.168.1.190 | 192.168.1.191 |
| 192.168.1.192/26 | 192.168.1.193 – 192.168.1.254 | 192.168.1.255 |
What is a subnet calculator?
A subnet calculator works out the details of an IPv4 network from an address and its prefix length (CIDR, such as /24) or subnet mask (such as 255.255.255.0). It shows the network address, broadcast address, first and last usable host, number of usable hosts, subnet and wildcard masks, IP class, whether the address is private or public, the reverse DNS zone and the binary representation, with network bits highlighted. You can also split the network into smaller subnets and check whether another IP belongs to it.
How to calculate a subnet
- Type an IP address with a prefix (192.168.1.10/24) or a mask (192.168.1.10 255.255.255.0).
- Adjust the prefix slider to see how the network changes.
- Read the network, broadcast, host range and masks; copy any value.
- Use Split into smaller subnets or the membership check for planning.
Subnetting essentials
- Usable hosts = 2^(32 − prefix) − 2; the network and broadcast addresses are reserved.
- /31 links have 2 usable addresses (RFC 3021) and /32 is a single host.
- Private ranges: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16 (RFC 1918).
- Wildcard mask = 255.255.255.255 − subnet mask, used in Cisco ACLs and OSPF.
Why use this subnet calculator
- Instant and exactResults update as you type, with copy buttons on every value.
- Learn as you goBinary view highlights the network and host bits so subnetting makes sense.
- Splitting built inDivide any network into equal smaller subnets and list each range.
- Nothing leaves your browserNetwork plans and internal addressing are calculated on your device, never logged by a server.
Common uses
- Network design. Plan VLANs and address blocks for offices and data centres.
- Firewall and ACL rules. Get the right wildcard and CIDR for rules.
- Cloud networking. Size AWS, Azure and GCP VPC subnets.
- CCNA and Network+ study. Check subnetting practice with the working shown.
More network tools: convert addresses with the binary to decimal and hex to decimal converters, or test endpoints with the API tester. Browse all developer tools.
Example: 192.168.1.10/24
Network 192.168.1.0 · Broadcast 192.168.1.255 · Hosts 192.168.1.1–192.168.1.254 (254 usable) · Mask 255.255.255.0 · Wildcard 0.0.0.255 · Private (RFC 1918).
What to expect from the result
This page calculates IPv4. Use the IPv6 subnet calculator for IPv6 prefixes. Cloud providers reserve extra addresses in each subnet (AWS reserves 5), so usable counts there are lower.
Subnet Calculator questions
How do I calculate the number of hosts in a subnet?
Hosts = 2^(32 − prefix) − 2. A /24 has 2^8 − 2 = 254 usable hosts; a /26 has 62.
What subnet mask is /24?
255.255.255.0. A /16 is 255.255.0.0 and a /28 is 255.255.255.240.
What is a wildcard mask?
The inverse of the subnet mask: 0.0.0.255 for a /24. Cisco ACLs and OSPF use wildcard masks.
Is my IP address private?
Addresses in 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16 are private (RFC 1918). The calculator labels private, public, loopback, link-local and other special ranges.
How do I split a network into subnets?
Choose a longer prefix with the split slider. A /24 split into /26 gives four subnets of 64 addresses each.