The manufacturing process of cement emits one metric ton of carbon dioxide greenhouse gas. Considering the situation reducing the gas emission without affecting cement production, industrial wastes like metakaolin (MK) can be partially replaced with cement due to high pozzolanic reactivity to arrive the high-strength concrete. This present examination attentions on the obtaining optimum percentage of metakaolin to be substituted for cement proportion and aims to determine the concrete sample’s mechanical characteristics, equivalent CO<inf>2</inf> emissions, and energy factor for environmental advantages through comparison with metakaolin varied from 0% to 20% at 5% incremental rate was determined and compared with the conventional control mix. Concrete samples are tested at the periodical interval of 7, 14, and 28 days in addition results, 5% of metakaolin is the optimum percentage to be replaced for cement in concrete. The negative sign implies that replacing binder with MK gradually decreases energy requirements (−2.16% to −7.74%) as well as carbon dioxide emissions (−4.17% to −15.41%). The use of mineral admixture like high reactive metakaolin additional cementitious elements has a considerable effect and may have an impact on the creation of environmentally friendly, sustainable concrete. In conclusion, effective utilization of high reactive metakaolin in high-strength concrete leads to substantial cost, and reducing global gas emissions eventually reduces energy consumption and a notable decrease in environmental pollution. © 2023 Elsevier B.V., All rights reserved.