Ready-Mix vs Bagged Concrete: When to Use Each (2026 Cost Comparison)

Use bagged concrete for projects under 0.5m\u00B3 (post holes, small repairs). Use ready-mix for anything over 0.5m\u00B3. It's cheaper per cubic metre, stronger, and saves hours of manual mixing.

MixHub TeamUpdated 22 March 2026

Side-by-Side Comparison

Every factor that matters when choosing between bagged premix and ready-mix concrete for a Sydney project:

FactorBagged Premix (20kg bags)Ready-Mix (truck delivery)
Best forUnder 0.5m³ (post holes, repairs, small paths)Over 0.5m³ (driveways, slabs, garages)
Cost per m³ (materials)~$864–1,296/m³ (108 bags × $8–12)$220–280/m³ delivered
Labour to place 1m³6–8 hours mixing + placing20–30 minutes to pour and screed
Maximum grade~N20 (20 MPa)N20 to N50+ (all grades available)
ConsistencyVaries; depends on your water ratioBatch-plant quality control, consistent slump
Minimum purchase1 bag ($8–12)Typically 1m³ (short-load fee under 3m³)
Equipment neededMixer or wheelbarrow + hoeFormwork only (truck does the mixing)
Physical effortHigh (108 bags × 20kg per m³)Low (pour, screed, finish)
Site access neededWheelbarrow access onlyTruck or pump access required

The Break-Even Point

The math is clear: ready-mix becomes cheaper than bags at around 0.5m³, and the gap widens dramatically from there. For a standard 4m³ driveway, ready-mix saves approximately $3,000–4,000 in material cost alone, before counting 24+ hours of mixing labour.

Example: 4m³ N25 Driveway, Bags vs Ready-Mix

Cost itemBagged concreteReady-mix (delivered)
Concrete material$4,320 (432 bags × $10)$1,000 (4m³ × $250/m³)
Mixer hire (1 day)$120$0
Delivery fee$0 (from hardware)$80
Labour (at $35/hr)$840 (24 hrs mixing)$70 (2 hrs pour + screed)
Total$5,280$1,150

Ready-mix saves approximately $4,130 on a 4m³ driveway. Even if you value your labour at zero, bags still cost $4,440 in materials vs $1,080 for ready-mix.

Note: bagged premix can't achieve N25, the strength required for most residential driveways per Australian Standards. So for a proper driveway, bags aren't just more expensive; they're not a like-for-like replacement.

When Bagged Concrete Makes Sense

Use bagged concrete when:

  • Your project is under 0.5m³ total (fence post holes, letterbox footings, small repairs)
  • Truck access is completely impossible (no driveway, narrow lane, upstairs balcony)
  • You need to work in stages over several days (bags give you flexibility)
  • You only need N20 strength (garden edging, blinding, decorative work)
  • You're in a remote location where ready-mix delivery adds >$200 in travel

The typical use case for bags is fence posts: 10 posts × 0.015m³ each = 0.15m³ total. At that volume, bags are the only sensible option. Two or three bags per post, mixed in a bucket, and you're done in an hour.

When Ready-Mix Wins

Use ready-mix concrete when:

  • Your project is over 0.5m³, where ready-mix is almost always cheaper
  • You need N25 or higher (driveways, structural slabs, footings)
  • You need a consistent, quality-controlled mix (batch plants produce to AS 1379 spec)
  • Time matters: a truck delivers in 20 minutes what would take a crew all day to mix
  • You need to pour in one continuous pour, since bags cool and set at different rates, creating cold joints

For a standard 4m × 5m garage slab at 100mm deep, you need 2m³. Even accounting for the short-load surcharge, ready-mix costs $700–800 delivered vs $2,160 in bags, plus a full day's mixing. Ready-mix wins by every measure.

Not sure how much concrete your project needs? Use the MixHub calculator to enter your dimensions and get a volume, grade recommendation, and Sydney price estimate.

How Many Bags Make 1 Cubic Metre?

A standard 20kg bag of premix concrete makes approximately 0.009–0.010m³ of concrete (9–10 litres). That means:

Volume needed20kg bags requiredCost (at $10/bag)Ready-mix equiv.
0.1m³11 bags$110~$340 (delivery min.)
0.25m³27 bags$270~$380 (delivery min.)
0.5m³54 bags$540~$430 (with short-load)
1m³108 bags$1,080$370–430 delivered
2m³216 bags$2,160$620–700 delivered

Source: CCAA (Cement Concrete & Aggregates Australia) mix ratio data. Ready-mix prices from Sydney market, March 2026.

Frequently Asked Questions

At what volume does ready-mix become cheaper than bags?
Ready-mix becomes cheaper at around 0.5m³. One cubic metre of bags costs approximately $864–1,296 in materials. Ready-mix costs $220–280/m³ delivered in Sydney (March 2026).
Can I get ready-mix for small jobs in Sydney?
Yes, but minimum orders are typically 1m³. Orders under 3m³ attract a short-load surcharge of $30–50/m³. For jobs under 0.5m³, bagged concrete avoids the delivery minimum.
How many 20kg bags make 1 cubic metre?
108 bags of 20kg premix make approximately 1m³. At $8–12 per bag, that’s $864–1,296 in materials — before factoring in 6–8 hours of mixing labour per cubic metre.
Is bagged concrete as strong as ready-mix?
Bagged premix typically achieves N20 (20 MPa). Ready-mix is available from N20 to N50+. For driveways requiring N25 or higher, ready-mix is the only practical option.
How do I calculate how much concrete I need?
Multiply length × width × depth (all in metres). For a 4m × 3m × 100mm slab: 4 × 3 × 0.1 = 1.2m³. Add 10% for wastage = 1.32m³. Use our calculator for an instant result.

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