It is known that regular concrete isn't very strong when it comes to pulling or stretching forces. Lately, stronger concrete has become a good choice for many projects because it deals with both strength and durability. To make regular concrete better while keeping its main properties, people use natural materials like metakaolin instead of some cement. This research is all about using metakaolin in concrete and checking how it acts when it's fresh and after it hardens. The main goal of this study is to see how metakaolin affects concrete. We tested different mixes by replacing 10%, 15%, and 20% of cement with metakaolin. We made four sets of concrete with different mixtures and tested their strength using standard cubes, cylinders, and prisms. We checked their strength after 7 and 28 days, as well as their flexibility and elasticity after 28 days. When we used more metakaolin in the concrete, we noticed a big change in how it behaved. The concrete became more fluid (we call this "slump") and took longer to set. We compared the results of these tests with regular concrete to see if using metakaolin is better for the environment and helps with sustainable development.