Method of measuring semiconductor device leakage which includes: providing a semiconductor device powered by a supply voltage and having a circuit block of transistors; providing on the semiconductor device a test circuit providing an input to a counter and a fixed-frequency measurement clock to provide a clock signal to the counter; disconnecting a system clock from the circuit block; receiving by the test circuit the supply voltage as an input; initializing the counter; starting the counter when the supply voltage is at or below a first voltage Vhigh; monitoring a decrease of the supply voltage with time; stopping the counter when the supply voltage is at or below a second voltage Vlow such that Vhigh is greater than Vlow; and reading the counter to provide the semiconductor device leakage metric. Also disclosed is an apparatus and a computer program product.