What does 5/3 or 4/3 mean on a concrete mixer?

Cement or concrete drum mixers are specified by capacity and output volume.

Using a 5/3 concrete mixer as an example, the numbers represent the following:

• The "5" (Input Capacity): This is the total volume in cubic feet of dry, unmixed materials (cement, sand, and aggregate) that the drum can hold.

• The "3" (Output Capacity): This is the actual amount in cubic feet of wet, mixed concrete produced per batch.

The second number is smaller because dry materials lose volume once they are mixed with water and the air gaps between the particles are filled.

A 5/3 concrete mixer takes up to 5 cubic feet of materials to mix into 3 to 3.5 cubic feet of concrete

Greenplant offers 4/3 and 5/3 drum mixers in our standard range (other sizes may be available - get in touch to discuss). Here's a quick overview of when to use a 4/3 mixer versus a 5/3 mixer.

When to Use a 4/3 Cement Mixer

The 4/3 drum mixer (approximately 90 litres mix output) is considered the standard "mini mixer" and is typically used for: 

• Small DIY projects: Ideal for minor tasks, such as setting fence posts, patching, or small patios.

• Mixing small batches: Its capacity is sufficient for situations where only a limited amount of material is needed at one time.

• Sites with limited access: This mixer is compact and designed to pass through a standard doorway. 

  
  

When to Use a 5/3 Cement Mixer

The 5/3 drum mixer (approximately 110-130 litres mix output) is a more heavy-duty option designed for professional and larger-scale use: 

• Bigger residential projects: Suitable for substantial tasks like larger driveways or patios.

• Commercial jobs: Often found on construction sites for medium-sized projects such as foundation work.

• Efficiency: Its larger drum capacity and opening allow you to mix larger volumes faster, making the job more efficient if significant quantities of concrete are needed. It can easily mix a full barrow load of concrete per batch, speeding up the process compared to a smaller mixer. 

Summary Comparison

Feature	4/3 Concrete Mixer	5/3 Concrete Mixer
Typical Mixed Output	Approx. 90 litres (~3 cubic feet)	Approx. 110-130 litres (~3 to 3.5 cubic feet)
Best Used For	Small tasks and DIY such as patching, post-setting, small patios	Larger residential projects such as driveways, small to medium commercial jobs
Portability	Highly portable; can typically fit through doorways	Less portable than 4/3; larger and heavier
Efficiency	Slower for large volumes as more batches are needed	More efficient for larger volumes; makes a full barrow load

For larger projects, you may also see 7/5 or 10/7 mixers, which follow the same naming convention but produce larger volumes. If you need a concrete mixer larger than a 5/3 mixer, please get in touch with our team to see how they can help.