Read ratios correctly
A nominal 1:2:3 ratio means one proportional volume of cement, two of sand, and three of coarse aggregate.
Keep all ingredient measurements on the same basis before scaling.
Scale the batch
Add the ratio parts to establish proportional shares, then scale each ingredient to the chosen batch basis.
Do not infer final concrete yield by simply adding loose ingredient volumes.
Control water separately
Water is not an arbitrary extra ratio part; water-cement ratio strongly affects concrete performance.
Use project specifications or qualified mixture-design data for structural work.
Verify the actual mix
Ready-mix and bagged products should be ordered from their stated yield and specification rather than reconstructed from a generic nominal ratio.
Confirm current supplier or project requirements before placement.