As mentioned above, there are diverse kinds of refractometers, all employing different measurement scales based on specific refractive index values. So the first step is determining which parameter you wish to measure.

The second step is to ensure that the measurement range is ideal for your application. Not all meters measure the full scale, and this is especially true for Brix meters. Narrow down your selection by browsing only those meters which measure your required range.

Once you have decided on a parameter and measurement range, an easy way to narrow your search is to choose between digital and optical refractometers. See below for some pros and cons of each meter type.

Automatic temperature compensation is fast becoming an essential feature for most refractometers. While ATC is not vital, it does act to increase the accuracy and speed of your measurements. Without ATC, you need to wait for both your sample and your meter to reach an ambient temperature to obtain an accurate reading. Where this is not possible, you need to calculate a temperature adjustment manually.

So you now know your scale, refractometer type, measurement range, and whether or not you want ATC. The fifth step is to determine your required accuracy level. Unfortunately, accuracy comes at a price. Generally, the higher the accuracy, the higher the meter's cost. In situations where accuracy is vital to product quality control, you need a very precise meter. In less critical circumstances, a broader accuracy range may be acceptable.