QFontMetrics::boundingRect() often returns a rectangle that is too narrow. I can reproduce this same behavior with QFontMetrics::boundingRect() and QFontMetricsF::boundingRect(). Some fonts work, some do not. QFontMetrics::tightBoundingRect() and QFontMetricsF::tightBoundingRect() also seem to fail, although it is more difficult to see because there is no drawText() method that can make good use of a QRect returned from tightBoundingRect(). (At least, not that I could figure out.) It seems to happen most with small fonts, which is why I have the QPainter scale transform, so the problem is easily seen. I first noticed this on a QGraphicsScene using QGraphicsItem elements that draw text.