CreteLab

Your intelligent concrete recipe calculator

Concrete properties

Select Cheap/Standard/Strong/Ultra Strong to load reasonable starting values.
Select a class according to structural requirements and usage.
Select all exposure classes relevant to your project; the most restrictive one ("governing") will be used for calculations.

Additional parameters (optional)

Finer gradations need more water, coarser gradations save water.
Available at hardware stores: CEM I 42.5 N (Portland cement, standard recommendation). CEM II is suitable for less demanding applications, CEM III for sulfate-resistant or lower-heat mixes.
Safety margin for target strength (B20 section 6.2). Typical: 3–5 for small batches, 9–12 for construction sites with unknown variability.
Enables moisture correction for aggregate. Without input: batch water = total water (no correction).

Additives (optional)

No admixture used.
WU = waterproof; improves resistance to water/pressure. Set 1-2% of cement weight.