Methods and systems are disclosed for determining a processor usage adjustment factor and for automatically applying the processor usage adjustment factor to provide a processor usage estimate for an SMT processor. In one implementation, the methods and systems obtain samples of processor usage reported by the operating system at a predefined sampling rate over a predefined sampling interval. Thread states for the threads substantially corresponding to the reported processor usage are so obtained at the predefined sampling rate and over the predefined sampling interval. This sampling may be performed for servers running different applications and having diverse processing loads. An estimate of the distribution of the number of threads running for the processor usage reported may then be determined from the sampled data. A processor usage adjustment factor may then be derived, based on the distribution, and used to provide a processor usage estimate.