Usage metering by bias temperature instability

Techniques for usage metering by bias temperature instability with differential sensing on pairs of matching transistors are provided. In one aspect, a usage metering device includes: at least one metering circuit on a chip, the at least one metering circuit having a pair of matching transistors, and a differential current sense circuit connected to the pair of matching transistors, wherein the pair of matching transistors includes a reference transistor which is unused during regular operation of the chip, and a stressed transistor that is on continuously during the regular operation of the chip, and wherein the differential current sense circuit determines a Vt difference between the reference transistor and the stressed transistor. A method for usage metering and a method of forming a usage metering device are also provided.