About

Knowing the total volume of concrete is only half the battle. On site, concrete is produced in small batches using portable mixers (e.g., Belle or generic drum mixers). A common error is overloading the mixer or miscalculating the number of batches, leading to a shortage of materials or inconsistent mixes.

This tool acts as a "Batch Splitter". It takes your total project volume, applies a standard waste margin, and divides it by the effective mixing capacity of your specific mixer (which is typically only 60-70% of the drum's geometric volume). It outputs the exact recipe per batch.

Formulas

The number of batches N is calculated using the effective yield, not the drum size:

N = V_total × (1 + W_%)V_mixer × E_eff

Where E_eff is the efficiency factor (approx 0.65 for tilted drum mixers).

Reference Data

Mixer Type	Geometric Vol	Mixing Capacity (Yield)	Batches per m³
Portable (Small)	100 L	65 L	~16
Standard Site (3.5cf)	140 L	90 L	~11
Professional (Large)	180 L	115 L	~9
Diesel Towable	300 L	190 L	~5.5

Frequently Asked Questions

A concrete mixer works by tumbling materials. If you fill it to the brim (geometric volume), the materials cannot fall and mix; they just rotate in a solid plug. Additionally, tilting the drum to mix prevents it from holding its full volume.

For simple footings, 5% is standard. For complex formwork or uneven ground (like digging trenches for foundations), allow 10% to 15% to account for ground irregularities and spillages.

The most accurate way is using "guage boxes" or buckets of known volume. Counting shovel loads is common but inaccurate. This calculator provides values in Liters, which maps easily to 10L or 15L builder's buckets.

Cubic Meter Concrete Volume & Batch Calculator

Recipe Per Mixer Load:

About

Formulas

Reference Data

Frequently Asked Questions