How to use the Subnet Mask Calculator
Overview
A practical guide to converting between CIDR and subnet masks and checking the network range.
Quick answer: Start by confirming the CIDR number, and add an IP address if you want to inspect the network and broadcast addresses. `/24` and `255.255.255.0` are the same idea in different forms.
1. Connect CIDR with dotted decimal
Network settings often use both `/24`-style CIDR notation and dotted decimal masks like `255.255.255.0`. If you are used to only one of them, this tool makes the relationship easier to see.
2. Check network and broadcast values
If you know the IP address, looking at the network and broadcast addresses shows the beginning and end of the range. That is useful when you want to estimate host counts or confirm allocation boundaries.
- Confirm the CIDR-to-mask mapping
- Check the start and end of the range
- Review usable host counts if needed
3. Where it helps in practice
It is useful for LAN planning, VPN checks, and IP allocation reviews. When you are unsure what to enter, pick either the CIDR or the subnet mask first and let the calculator fill in the rest.
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