On my approx tires 90psi, it shows around 5psi (tested with 3 gauges). This seems like overvariance, but if you know it's different by x% (about 6% in my case) you can handle it - I will. acceptable deviation (but then you could just use a $3 pencil meter and get that kind of accuracy). If accurate tire pressure is important for high-pressure tires, this is not a good buy at this price point.