IPv4 calculator
- Network address
- 203.0.113.0
- Broadcast address
- 203.0.113.255
- First usable host
- 203.0.113.1
- Last usable host
- 203.0.113.254
- Usable hosts
- 254
- Total addresses
- 256
- Subnet mask
- 255.255.255.0
- Wildcard mask
- 0.0.0.255
- CIDR notation
- 203.0.113.0/24
- Address range
- 203.0.113.0 – 203.0.113.255
- Class
- C
- Scope
- Public
- Mask in binary
- 11111111.11111111.11111111.00000000
- Address in binary
- 11001011.00000000.01110001.00101101
- Subnets of /26
- 4
- Usable hosts in each
- 62
- Smallest block for 50 hosts
- /26
Calculated in your browser · nothing is looked up or uploaded
Shows an IPv4 address in dotted decimal and binary, with its class, scope and the network it sits in at any prefix length.
How to use the ipv4 calculator
An IPv4 address is one 32-bit number. The dots are punctuation for humans — 192.168.1.1 and 3232235777 are the same value, which is why a URL of http://3232235777/ works in most browsers and why that trick appears in phishing links.
The binary view is what makes subnetting make sense. Line the address up under the mask and the split is visible: everything above the boundary is the network, everything below is the host. Most subnetting confusion evaporates once you have looked at the two rows together a few times.
The address space has fewer usable addresses than the 4.3 billion the arithmetic suggests. 0.0.0.0/8, 127.0.0.0/8 (loopback), 169.254.0.0/16 (link-local), the three RFC 1918 blocks, 100.64.0.0/10 (carrier-grade NAT), 224.0.0.0/4 (multicast) and 240.0.0.0/4 (reserved) are all carved out — roughly 600 million addresses that cannot be used on the public internet. The last free blocks were allocated in 2011, which is the whole reason IPv6 exists.
Questions
Yes, one 32-bit number. The dots are for humans — and http:// followed by the plain number often works, which is a phishing trick.