Subnet Reverse Calculator

Reverse calculate subnet information from IP address ranges. Free online subnet reverse calculator to determine subnet mask and CIDR notation.

Subnet Reverse Calculator

How to Use Subnet Reverse Calculator

This tool calculates the optimal subnet configuration for a given IP address range:

  • Start IP: The first IP address in your desired range
  • End IP: The last IP address in your desired range
  • Recommended Subnet: The most efficient subnet mask for your range
  • Alternative Options: Other subnet configurations that could work

Enter the start and end IP addresses of your desired range to find the best subnet configuration.

Subnet Reverse Calculation Examples

IP RangeRecommended SubnetCIDRTotal IPs
192.168.1.1 - 192.168.1.254255.255.255.0/24256
10.0.0.1 - 10.0.0.62255.255.255.192/2664
172.16.0.1 - 172.16.0.30255.255.255.224/2732
192.168.1.1 - 192.168.1.126255.255.255.128/25128