In this article, we explained how to determine the concrete mix ratio in relation to the number of head pans of sands and gravels that are actually needed for a bag of cement and How much sand and gravel need for a bag of cement.
Concrete Grade Full list :- https://civilengineeringqs.com/what-is-the-types-of-concrete-grade-used-in-construction-compressive-strength-for-various-grade-of-concrete-mix-ratio-for-different-grades-of-concrete/
That's 8 bags of cement, 15 CFT of sand and 30 CFT of aggregate are required for one cubic meter (1m3) of M20 concrete. A typical M20 grade of concrete requires 8 bags of cement, 15 CFT of sand and 30 CFT of aggregate per cubic meter.
The key to achieving the psi strength labeled on a bag of concrete is keeping the water-to-cement ratio as low as possible without sacrificing workability. Adding too much water can cause a host of problems. - Fine Homebuilding