JB Tool - Subnet Calculator

Calculate IPv4 and IPv6 subnets directly on your Android device.

Enter an address and prefix:
• Enter an IPv4 or IPv6 address with an optional CIDR prefix
• Use a prefix length or dotted IPv4 subnet mask
• Select commonly used prefixes with one tap

Review detailed results:
• Network CIDR and network address
• Broadcast address for IPv4
• First and last addresses and the usable host range
• Total addresses and usable host count
• Subnet mask and wildcard mask
• Clear notes for IPv4 /31 and /32 networks and IPv6 behavior

Copy individual values or share the complete result through another app.

All calculations run offline on your device. Inputs and results are not saved. No account is required, and the app contains no ads, analytics, tracking, or network permission.