IP Subnet Calculator
CIDR to network, broadcast, host range and mask.
Network
10.0.4.0
Broadcast
10.0.7.255
Netmask
255.255.252.0
Wildcard
0.0.3.255
First host
10.0.4.1
Last host
10.0.7.254
Total addresses
1,024
Usable hosts
1,022
10.0.4.0/22 — cloud providers typically reserve 5 addresses per subnet.
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About this tool
CIDR notation splits an address into a network prefix and a host portion. This calculator derives every value you need when planning VPC subnets or writing firewall rules.
Planning VPC subnets
Reserve a large block such as 10.0.0.0/16, then carve /24s per tier and availability zone. Cloud providers typically reserve five addresses per subnet.
Reading prefix lengths
Each extra bit halves the block: /24 holds 254 usable hosts, /25 holds 126, /26 holds 62.
How to use IP Subnet Calculator
- 1
Open IP Subnet Calculator
Everything runs on this page — there is nothing to install and no account required to use the free features.
- 2
Add your input
Paste or enter your values in the panel above. The tool updates as you type, so you can iterate quickly.
- 3
Review the output
Check the result, copy it with one click, and adjust the options until it matches what your system expects.
- 4
Take it further
Use the security & infrastructure tips below to make the result production-ready, then unlock the gated extras via the form above.
Best practices
- Treat every result as a snapshot — configuration drifts, so re-check after each deploy.
- Fix the highest-impact finding first rather than chasing a perfect score.
- Apply changes at the shared layer (proxy, CDN, base image) so every service inherits them.
- Document what you changed and when; auditors and future teammates will ask.
Why IP Subnet Calculator matters
Infrastructure and security misconfigurations are among the most common root causes of real incidents, and almost all of them are cheap to fix once visible.
Leaving them unaddressed means failed audits, blocked enterprise deals, and avoidable exposure.
Related free & paid tools
| Tool name | Type | Key features | Link |
|---|---|---|---|
| ipcalc | Free | CLI subnet maths on Linux and macOS | Visit |
| AWS VPC planner docs | Free | CIDR sizing guidance for cloud networks | Visit |
| SolarWinds IP Address ManagerOffer | Paid | Enterprise IPAM with subnet discovery | Visit |
Links marked Offer may be partner links. They cost you nothing extra and never affect which tools we recommend.