Subnet / CIDR Hosts
Developer
Usable hosts in an IPv4 subnet.
Hosts = 2^(32 − cidr) − 2
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Runs locally in your browser
2 calculators
Developer
Plan subnets in CIDR notation and convert hex to RGB without leaving your keyboard. Everything computes client-side in your browser, so nothing you type is logged.
- Calculators in this category
- 2
- Tools
- Cost
- Free
- Forever
- Result type
- Live
- Results
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Terse inputs, instant outputs, and the underlying math documented below each tool.
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Why use these calculators
Client-side by default
Conversions and subnet math run locally in your browser. Nothing you paste is sent anywhere.
Precise, documented output
CIDR results include network, broadcast, and usable host ranges, with the underlying bit math explained.
Keyboard-speed workflow
Live recalculation with no submit step, so you can iterate on values as fast as you can type.
Frequently asked questions
It is the number of fixed network bits in an address. A /24 leaves 8 host bits, giving 256 addresses with 254 usable hosts. The subnet calculator shows the full breakdown for any prefix.