A method of estimating aging of an integrated circuit (IC) includes: obtaining a first process design kit (PDK) including a plurality of first device models corresponding to a plurality of devices provided by a process of fabricating the IC; obtaining values of aging parameters of device instances included in a netlist defining the IC, by performing a first circuit simulation based on the netlist and the first PDK; and obtaining aging data of the IC by performing a second circuit simulation based on the values of the aging parameters and the netlist, wherein each of the plurality of first device models includes at least one measurement command to be executed in the first circuit simulation to calculate an aging parameter.