Aisha K.
Mar 12, 2026
Clean layout and the results update instantly. Exactly what I needed for a quick planning check.
Networking & IT Infrastructure
Subnet Calculator — IP Ranges, Host Count & Subnet Mask
Hosts = 2^(32 − prefix) − 2; mask bits = prefix; usable range excludes network and broadcast.
Map CIDR prefix length to subnet mask, total addresses, and usable host count for IPv4 networks. Planning estimates only — verify with production tools and vendor pricing where applicable.
Inputs
830
164
Smart analysis
Recommendations
Tailored to your live inputs and result—guidance only, not professional advice.
- Interpret
Treat this as a planning estimate
Primary result: Usable hosts = 254. Re-run with optimistic and pessimistic inputs to understand the range—not just a single point.
Scenario studio
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Scenario A
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Scenario B
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Plain-English guide
Terms & how it works
Confused by a field? Read the short definitions here while you use the tool.
CIDR prefix (/n)
The “CIDR prefix (/n)” value used in this tool’s formula. Adjust it to see results update live.
Subnets needed
The “Subnets needed” value used in this tool’s formula. Adjust it to see results update live.
How this calculator works
Map CIDR prefix length to subnet mask, total addresses, and usable host count for IPv4 networks. Planning estimates only — verify with production tools and vendor pricing where applicable. Hosts = 2^(32 − prefix) − 2; mask bits = prefix; usable range excludes network and broadcast. Example: /24 → 256 addresses, 254 usable hosts, mask 255.255.255.0.
Hosts = 2^(32 − prefix) − 2; mask bits = prefix; usable range excludes network and broadcast.
Example: /24 → 256 addresses, 254 usable hosts, mask 255.255.255.0.
When to use this Subnet
Common use cases
- Map CIDR prefix length to subnet mask, total addresses, and usable host count for IPv4 networks.
- Sanity-check with this case: /24 → 256 addresses, 254 usable hosts, mask 255.255.255.0.
- The relationship is: Hosts = 2^(32 − prefix) − 2; mask bits = prefix; usable range excludes network and broadcast.
Localized examples
- Networking & IT Infrastructure: the example on this page uses the same formula as the widget.
What you get
- Fields: CIDR prefix (/n), Subnets needed
- Hosts = 2^(32 − prefix) − 2; mask bits = prefix; usable range excludes network and broadcast.
- Example on the page: /24 → 256 addresses, 254 usable hosts, mask 255.255.255.0.
How to Calculate Subnet Step-by-Step
- 1Enter CIDR prefix (/n), Subnets needed. Use the values you have, not a catalog average, unless that is all you know.
- 2Hosts = 2^(32 − prefix) − 2; mask bits = prefix; usable range excludes network and broadcast.
- 3Worked case: /24 → 256 addresses, 254 usable hosts, mask 255.255.255.0.
- 4Compare the result to last month’s invoice or a vendor calculator before you commit capacity.
Governing formula
Hosts = 2^(32 − prefix) − 2; mask bits = prefix; usable range excludes network and broadcast.
/24 → 256 addresses, 254 usable hosts, mask 255.255.255.0.
Example: set CIDR prefix (/n) = 24, Subnets needed = 1, then read the result.
Variable definitions
- cidrPrefix
CIDR prefix (/n)
The “CIDR prefix (/n)” field. Default 24; typical range 8–30.
- subnetsNeeded
Subnets needed
The “Subnets needed” field. Default 1; typical range 1–64.
- Closed-form math (Hosts = 2^(32 − prefix) − 2; mask bits = prefix; usable range excludes network and broadcast.) misses idle time, egress, packet loss, and reserved capacity on the real bill.
- Nothing here is uploaded for the calculation itself.
Frequently Asked Questions
Hosts = 2^(32 − prefix) − 2; mask bits = prefix; usable range excludes network and broadcast.
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Community
Reviews & Ratings
See what others think about this tool, then leave your own rating to help improve CalculioHub.
4.8
out of 5.0
4 reviews
Daniel R.
Feb 28, 2026
Very usable on mobile. Would love a save/export option later, but the math feels solid.
Priya S.
Feb 3, 2026
The FAQ section answered my questions before I even had to search. Smooth dark mode too.
Marcus L.
Jan 19, 2026
Simple inputs, clear outputs. This replaced three bookmarks I used to juggle.
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