This article presents an implementation of well known method for fundamental frequency measurement. The algorithm uses FFT and searches for a peak in spectrum. Dominant frequency is then recalculated to tone name used in music. The presented computer program basically works in similar way to commercially sold tuners for musical instruments and also many other software tuners widely available in the internet, but what makes it unique is the peak search algorithm and reliable matching of higher harmonics. Moreover, the programme is written in Python programming language with a great help of !Scipy. This makes it surprisingly simple to implement and easy to understand and modify. It runs under Linux and uses alsa for sound recording.