Quick take
Work out subnet ranges, masks, and host counts without manual math.
- Calculate 192.168.1.10/24 to find the network address and broadcast address.
- Inspect 10.0.0.0/16 for total addresses and usable host range.
CIDR Calculator
| Network address | 192.168.1.0 |
|---|---|
| Broadcast address | 192.168.1.255 |
| Subnet mask | 255.255.255.0 |
| Wildcard mask | 0.0.0.255 |
| First usable IP | 192.168.1.1 |
| Last usable IP | 192.168.1.254 |
| Total addresses | 256 |
| Usable hosts | 254 |
| Address class | Class C |
Binary view
IP: 11000000.10101000.00000001.00001010 Mask: 11111111.11111111.11111111.00000000
| Subnet | Range | Addresses |
|---|---|---|
192.168.1.0/26 | 192.168.1.0 - 192.168.1.63 | 62 |
192.168.1.64/26 | 192.168.1.64 - 192.168.1.127 | 62 |
192.168.1.128/26 | 192.168.1.128 - 192.168.1.191 | 62 |
192.168.1.192/26 | 192.168.1.192 - 192.168.1.255 | 62 |
Where it fits
Use CIDR Calculator for understanding IPv4 and IPv6 ranges during firewall changes, allowlists, subnet planning, and security scoping. It works well when you want network address, first and last addresses, masks, counts, and subnet previews and do not need a bigger workflow around it.
- Best fit: understanding IPv4 and IPv6 ranges during firewall changes, allowlists, subnet planning, and security scoping.
- You start with an IP address or network with a CIDR prefix.
- The useful choices are IPv4 or IPv6 mode, prefix length, and whether to split into smaller subnets.
- Check range boundaries, address count, broadcast behavior for IPv4, and whether the scope is too broad.
- You end up with network address, first and last addresses, masks, counts, and subnet previews.
What the output does and does not prove
- IPv4 addresses are calculated as 32-bit values and IPv6 addresses as 128-bit values in the browser.
- The tool derives network, range, address counts, subnet splits, and IPv4-only fields such as broadcast and wildcard mask where applicable.
- Subnet splitting previews the first 16 deterministic child networks for a larger target prefix.
A clean way to use CIDR Calculator
- Start with an IP address or network with a CIDR prefix.
- Choose IPv4 or IPv6 mode, prefix length, and whether to split into smaller subnets.
- Run the tool once, then review range boundaries, address count, broadcast behavior for IPv4, and whether the scope is too broad.
- Copy, export, or download network address, first and last addresses, masks, counts, and subnet previews.
- Treat the output as one checkpoint, then verify the next step in the real workflow.
What to watch for
- IPv4 calculations use 32-bit ranges and IPv6 calculations use 128-bit ranges with different conventions.
- IPv6 has no broadcast address, so IPv4-only fields should not be forced onto IPv6 results.
- Verify ownership and intended scope before scanning, blocking, or allowlisting a CIDR range.
- Use smaller prefixes when documenting security scope to avoid accidental overreach.
How your data is handled
All CIDR and subnet calculations run in your browser. Toolumina does not upload, save, or log the IP ranges you enter.
FAQ
Does this support IPv6?
Yes. IPv6 CIDR ranges are calculated locally, with broadcast and dotted-decimal mask fields marked as not used for IPv6.
Why does /32 have one usable address?
/32 represents a single exact address rather than a traditional multi-host subnet.
Why is /31 different from /30?
/31 is commonly used for point-to-point links, where both addresses can be usable.
Is any network scan performed?
No. The tool only performs local arithmetic on the address and prefix you enter.