Efforts to intensify cassava production have been stymied by weed infestations, which are mostly controlled by the use of hand (hoe) weeding?a system that is crude and drudgery-driven. Women spend hundreds of hours per annum to weed cassava (hoe weeding takes 50 to 80% of the total labor budget in Nigeria) .In some cases, children are withdrawn from school to support weeding. To avoid the drudgery of hoe weeding, many rural farming communities in Africa are using herbicides with the help of knapsack sprayers. However, the challenge many farmers face is mostly wrong application of herbicides as many cannot manually calculate the quantity of herbicide needed to load in the sprayer per given operation. The IITA Herbicide Calculator was developed by IITA using in house capacity to help farmers and applicators of herbicides to calibrate themselves and apply the right quantity of herbicide per knapsack spray tank to avoid either over dosing or underdosing which leads to poor weed control , economic waste, development of resistant weeds, and environmental pollution.