Carbon nanotubes (CNTs) possess range of properties which are useful in applications like, H2 storage, electrodes in fuel cell, catalyst support in chemical industry, electronic components, etc. Normally, high yield is desirable from the cost reduction point of view, hence knowledge of carbon deposition in the presence of various catalysts loading is required. In this paper, optimization of catalyst loading to obtain effective utilization of the feed stock, which obtains cost reduction of CNTs is presented. The Fe–Co metal catalyst is used in the study. The carbon precursor used in the study is C2H2 along with Ar as a carrier gas. The carbon deposition is carried out at optimized temperature of 700°C. The experiments are carried out at different concentration of the feed stocks (C2H2 : Ar) such as 0.06:1, to 0.28:1, so as to compare the effect of carbon loading. Since, at higher concentration, the amount of carbon generated is more, hence, sufficient catalyst should be present such that it assures the maximum utilization of the decomposed carbon. The 8.1 and 42.4 mgcatalyst is required for maximum utilization of feed stock at 30 min of precursor flow at lowest and highest concentration. It is observed that the catalyst loading shows a linear relationship with an increase in the concentration of feed stock and the time of the CNTs synthesis.