Calculate IP Subnets and Netmasks Select a Calculator: IP Range Mask Optimizer CIDR Subnet Mask Calculator Subnet Mask Calculator IP Range Mask Optimizer This tool calculates optimal netmasks for covering any range of IP addresses. Depending on the range of IP addresses entered, the result can be multiple masks. CIDR Subnet Mask Calculator Select Subnet Mask /24 /16 /8 ---------------------- /0 /1 /2 /3 /4 /5 /6 /7 /8 /9 /10 /11 /12 /13 /14 /15 /16 /17 /18 /19 /20 /21 /22 /23 /24 /25 /26 /27 /28 /29 /20 /31 /32 Subnet Mask Calculator