IP Subnet Calculator
Calculate subnet mask, network address, and host range.
You might also need
How It Works
Usable hosts = 2^(32-prefix) - 2. Subtract 2 for network address and broadcast address which cannot be assigned to hosts.
Formula
Network = IP AND MaskQuick Reference
Common calculations — results you can verify instantly.
/24 subnet
2^8-2
254 hosts
/16 subnet
2^16-2
65,534 hosts
/30 subnet
2^2-2
2 hosts (point-to-point)
Tips & Shortcuts
/24 = 254 hosts. /16 = 65534 hosts. /8 = 16.7M hosts.
CIDR /24 means 24 bits for network 8 bits for hosts.
Common Mistakes
Forgetting to subtract network and broadcast
Two addresses reserved: network (all 0s) and broadcast (all 1s).
Confusing prefix length with subnet mask
/24 = 255.255.255.0. /16 = 255.255.0.0. /8 = 255.0.0.0.
Frequently Asked Questions
2^(32-24)-2 = 254 usable hosts.
Classless Inter-Domain Routing. /prefix shows how many bits are network bits.
Related Calculators
URL Encoder Decoder
Encode or decode URL strings for safe web transmission.
Big Number Calculator
Perform arithmetic on numbers with hundreds of digits.
Binary Calculator
Add, subtract, multiply binary numbers and convert to decimal.
Fuel Cost Calculator
Estimate the total fuel cost for any trip based on distance, fuel price and efficiency.
Gas Mileage Calculator
Calculate MPG from miles driven and gallons used.
Mileage Calculator
Calculate mileage reimbursement for business driving.