Abstract: A data totalizer for use with a fluid flow chart recorder is disclosed. The chart recorder may be for a gas well to record the flow of gas into a collection pipe and such chart recorder has a movable chart, usually a circular chart, with a first marker pen to record on the chart a static pressure within the pipe collection system and a second marker pen to record on the chart a fluid flow signal in accordance with a differential pressure across an orifice in the gas well pipe, and with first and second fluid pressure motors in the chart recorder to move the first and second marker pens. The data totalizer includes first and second linear variable displacement transformers, with linkage connected directly in the chart recorder to move in accordance with movements of the pens and connected to move the linearly displaceable elements in the two transformers. An electronic multiplier is provided to multiply together the electrical outputs of the first and second transformers to obtain a product.