IPv4 Subnet Calculator
A compact CIDR calculator for network debugging, firewall rules and cloud VPC planning. Enter an IPv4 address with prefix and get the full subnet report instantly.
subnet report
- Address
- 192.168.10.42
- CIDR
- /24
- Netmask
- 255.255.255.0
- Wildcard
- 0.0.0.255
- Network
- 192.168.10.0
- Broadcast
- 192.168.10.255
- First usable
- 192.168.10.1
- Last usable
- 192.168.10.254
- Usable hosts
- 254
- Total addresses
- 256
runtime
Browser-local execution
Inputs stay inside the current tab unless you copy, download or explicitly export.
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User-owned state
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smart handoff graph
session handoff readySuggested next moves
01
How to use
- 01Enter an IPv4 CIDR such as 192.168.10.42/24.
- 02Review network, broadcast, netmask and host range.
- 03Copy the full subnet report when documenting rules.
02
FAQ
- Does it support IPv6?
- Not in this tool. It focuses on fast IPv4 CIDR math. IPv6 planning deserves a separate interface.
- How are /31 and /32 handled?
- They are treated as point-to-point or single-address ranges with zero traditional usable hosts.
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