Abstract: An improved "reference" pipet tip supports a number of volume scale ranges on its external body--preferably a scale for each of small volumes 0.5 microliters through 5 microliters, medium volumes 5 microliters to 50 microliters, and large volumes of 50, 100, and 150 microliters--because the geometry of its interior reservoir is non-uniform. In particular, the pipet tip's interior reservoir increases in diameter, and in contained volume, at a first rate, and in response to a first conical angle of rotation, at its distal end, tip, region. The interior reservoir increases at a different, larger, rate at its proximal end region, which proximal end region is connected to a pipettor. Fluid volumes in a broad range from. 0.5 microliters to 150 microliters are typically measurable at accuracies of better than 10%.