bags on cement in yard in Perth for Statewide Building Supplies

Cement is a binder used in construction that hardens and adheres to other materials. It’s rarely used on its own—mixed with fine aggregate it becomes mortar. Mixed with sand and gravel, it becomes concrete.

In this article, we’re going to give you a complete fact sheet including everything you need to calculate the amount of cement needed.

The different metric units and why they matter

When people ask “bags of cement per m³” they’re using metric units:

m - metres = length (the length of a wall)

m² - square metres = area (floor area, wall area to be rendered/painted/covered)

m³ - cubic metres = volume (how much concrete you’re pouring)

 

Where each unit is used in building

m² is used when you’re covering a surface: render areas, slab area, wall area, etc.

m³ is used when you’re ordering or mixing something by volume: concrete for slabs/footings, mortar volumes, sand/aggregate quantities, etc.

How to calculate them

Area (m²) for rectangles:

Area = length × width

Volume (m³) for rectangular pours (slabs/paths/footings):

Volume = length × width × thickness

Thickness conversions (common mistake)

100 mm = 0.10 m

50 mm = 0.05 m

10 mm = 0.01 m

5 mm = 0.005 m

See all the cement available from Statewide Building Products here.

 

How many bags of cement to make 1m³ of concrete?

There isn’t one fixed number required. It depends on the strength/workability you’re targeting and whether it’s site-mixed vs specified mix design.

A practical way to estimate is to use cement content (kg of cement per m³ of concrete), then convert to bags.

Typical cement contents used for estimating

Many general concretes land roughly in the 300–400 kg of cement per m³ range (higher strengths often use more cementitious material).

Convert kg into bags (the only formula you really need)

bags = cement required (kg) ÷ bag size (kg)

How many bags of cement for 1m³ concrete

Cement content (kg per m³) 20kg bags 25kg bags
300 kg 15 bags 12 bags
320 kg 16 bags 13 bags
360 kg 18 bags 15 bags
400 kg 20 bags 16 bags

 

A very common estimate is 16–20 bags of 20kg cement per 1m³ of concrete, depending on the mix design.

 

Specific volume case: 0.5 m³

Just halve it:

Example: 320 kg/m³ → 0.5m³ needs 160 kg → 8 × 20kg bags

 

How many bags of GP cement per m³ (cement powder only)?

To answer this question, you need bulk density.

Cement bulk density (loose) is commonly approximated around 1400 kg/m³ (it varies by product and how it’s packed/settled).

  • 1m³ of cement powder ≈ 1400 kg
  • 20kg bags ≈ 70 bags
  • 25kg bags ≈ 56 bags

This is mainly useful for conversions—not for concrete ordering.

 

How many cubic meters in a 20kg bag of cement

Using ~1400 kg/m³:

Volume = 20 ÷ 1400 = 0.0143 m³ (≈ 14.3 L)

So, a typical estimate is:

20kg bag ≈ 0.014m³ (≈ 14L)

 

How many shovels are there in a bag of cement? (20kg bag)

This depends entirely on your shovel volume.

A reasonable range is often ~3–6 shovels per 20kg bag, depending on shovel and how heaped it is.

Examples:

  • If your shovel holds ~3 L: ~5 shovels
  • If your shovel holds ~4 L: ~3.5 shovels

 

How many 20kg bags of cement are on a pallet?

Pallet quantities vary by product, so the safest answer is checking the specific product listing.

At Statewide Building Products, we generally sell 56 bags per pallet.

 

How many square meters in a 20kg bag of cement?

Cement alone isn’t normally applied as a “coverage product”; coverage depends on the mix and thickness.

Method:

  • Convert thickness to metres
  • Calculate volume: V = area × thickness
  • Convert volume into cement bags using your mix design

Example (render-style estimate)

If you apply 10 mm thick render to 10m²:

  • Volume = 0.10 m³
  • At 1:5 mix → cement ≈ 0.0167 m³
  • Bags ≈ 1.2 → allow ~2 bags after waste

 

How many bags of cement per 1000 bricks?

Brick mortar quantities vary based on:

  • Brick size
  • Joint thickness
  • Wastage
  • Mortar mix

A practical planning range:

  • Mortar volume: 0.25–0.35m³ per 1000 bricks

Example:

  • 0.30m³ mortar at 1:5 mix → cement ≈ 0.05m³
  • ≈ 4–5 bags (20kg)

A sensible estimate is ~4–6 bags per 1000 bricks.

 

FAQ

How many bags of cement do I need?

  • Determine if it’s concrete, mortar, or render
  • Calculate volume in m³
  • Choose mix design
  • Convert using: bags = kg ÷ bag size

How many bags of cement to make 1m³?

Concrete: ~16–20 bags (20kg)

Cement powder: ~70 bags (20kg)

How many bags of cement for 0.5m³?

Half of the 1m³ quantity.

Example: 16 bags → 8 bags