A scoping study, involving literature and web review, telephone surveys and focus groups, was undertaken to assess the need, format and benefits of having a pasture weed impact calculator for southern Australia temperate grazing systems to underpin a compelling case for control. Through the telephone survey and focus groups it was clear that there was strong demand for and important benefits of a calculator. Graziers particularly recommended that the impact of weed infestation (measured in % weed coverage and identified through representative photographs) on pasture production be translated into direct economic measures. The extensive review of literature showed that there is minimal pasture-weed impact data currently available at a farm or paddock level. However, such information was reported to assist graziers in weed control decision making and encourage control. The literature review also demonstrated the positive effect weed impact data would have on grazier’s motivations and barriers to weed control and the grazier’s pest management decision making. Of the graziers surveyed, 98% reported that they would be motivated to control weeds if a significant impact to grazing operations was demonstrated. With graziers made more aware of the impact weed infestations have on their production, this will lead to improved weed control planning and action. The findings support the development of a project subsequent to this scoping study to gather weed impact data at a farm or paddock level, develop communication and extension material and a pasture weed impact calculator. These recommendations would produce a new motivational tool to increase weed management by graziers, including the more reluctant weed managers. This change in practice would be achieved by demonstrating to graziers the direct link between weeds in the paddock, at different % coverage levels, and the impact on their stocking rates and pasture production. The benefits to industry, of having a pasture weed impact calculator, include increased weed control and reductions in weed spread, increased pasture production/stocking rates, and an improvement in livestock health.