Precision

The different types of levels can be further divided into different classes defined by their precision:

Precise
Very accurate instruments for geodetic networks, monitoring surveys or any other very precise levelling. Instruments in this class are tilting or automatic types and can be levelled within approximately +/-0.2" of a horizontal line.

Medium Accuracy
These are used for engineering surveys and small control networks. Instruments in this class are tilting or automatic types and can be levelled within approximately +/-1" of a horizontal line.

Builders
Used for low accuracy, short range levelling such as setting out on building sites. Although described as being low accuracy instruments, this is relative to the other classes of levels and the results obtained with this class of instruments will be well within the tolerances required on the majority of construction sites. Instruments in this class are tilting or dumpy types and can be levelled within approximately +/-10" of a horizontal line or plane.