This International Standard specifies a method and the device for use in determining the position of the seat index point (SIP) for any kind of seat designed for earth-moving machinery as defined in ISO 6165, and tractors and machinery for agriculture and forestry as defined in ISO 3339-0. This provides a uniform method for defining the location of the SIP in relation to a fixing point on the seat. The SIP may be determined on a seat by itself or with the seat located in its operating environment on the machine. The SIP is a characteristic of the seat; therefore, it may be specified by the seat manufacturer.