How to Calculate How Much Aggregate You Need (The Simple Formula + Coverage Guide)

A contractor in Ealing ordered 8 tonnes of MOT Type 1 for a driveway base. Used 12 tonnes. Project stopped for three days waiting for more delivery. Cost him the delay, extra delivery charges, and looking unprofessional to his client.

Last week, someone else ordered 15 tonnes of topsoil for turfing. Used 9 tonnes. Left with 6 tonnes of unused material sitting in their yard, already paid for, going to waste.

Here's the truth: most people get aggregate calculations wrong. Not because the math is hard—because they don't know the depths, don't account for material differences, and guess at quantities.

Here's how to calculate exactly what you need.

The Simple Formula (Works for All Aggregates)

Every aggregate calculation starts with the same basic formula:

Length (m) × Width (m) × Depth (m) = Volume in cubic metres (m³)

Then convert to tonnes based on material density.

Example:

• Driveway area: 10m long × 5m wide
• MOT Type 1 depth: 150mm (0.15m)
• Calculation: 10 × 5 × 0.15 = 7.5 cubic metres

But here's what nobody tells you: 1 cubic metre of MOT Type 1 weighs about 2.1 tonnes.

So: 7.5m³ × 2.1 = 15.75 tonnes needed

That's the basic formula. The complications come from material type, application depth, and wastage—which we'll cover below.

Why Material Type Matters (Density Variations)

Not all aggregates weigh the same per cubic metre. Some materials are bulkier and lighter, others are denser and heavier.

Approximate material densities:

• MOT Type 1: ~2.1 tonnes per m³
• Sharp Sand: ~1.7-1.8 tonnes per m³
• Ballast: ~1.75-1.8 tonnes per m³
• Topsoil: ~1.4-1.7 tonnes per m³ (varies by moisture)
• Building Sand: ~1.6-1.7 tonnes per m³

This is why two projects with the same volume need different tonnages. A 10m³ job needs 21 tonnes of MOT Type 1 but only 15 tonnes of topsoil.

The shortcut: Use the formula to get cubic metres, then tell your WasteHub Account manager the area size and material type. We'll calculate exact tonnage based on actual material density—no guesswork.

Standard Depths for Common Applications

Getting the depth wrong is where most calculations fail. Here are the industry-standard depths for typical projects:

MOT Type 1 Depths (SHW Clause 803 certified)

Driveways (car traffic):

• Standard cars: 150mm depth (compacted)
• Heavy vehicles/commercial: 200mm depth (compacted)

Patios and paving:

• Residential patios: 100mm depth (compacted)
• Light foot traffic areas: 75-100mm depth (compacted)

Paths and walkways:

• Standard footpaths: 75mm depth (compacted)
• Heavy foot traffic: 100mm depth (compacted)

Foundation sub-base:

• Building foundations: 150-200mm depth
• Shed/summerhouse bases: 100-150mm depth

IMPORTANT: These are COMPACTED depths. MOT Type 1 compacts by approximately 10-15%. If you need 150mm compacted depth, lay 165-175mm loose material.

Sharp Sand Depths

Paving bedding layer:

• Block paving: 50mm depth
• Patio slabs (mortar bed): 50mm depth
• Pointing/jointing: 30-40mm depth

Screed and concrete:

• Floor screeds: 50-75mm depth
• Concrete mixing: As per mix ratio requirements

Sharp sand doesn't compact significantly compared to MOT Type 1, so your laid depth equals your final depth.

Topsoil Depths

Turfing and lawns:

• New turf installation: 100-150mm minimum depth
• Lawn repair/levelling: 50mm depth
• High-quality established lawns: 150-200mm depth

Planting and beds:

• Flower beds and borders: 150-200mm depth
• Vegetable gardens (root crops): 300-400mm depth
• Vegetable gardens (surface crops): 150-200mm depth
• General landscaping: 100-150mm depth

BS3882:2015 certified topsoil provides the nutrient-rich base needed for healthy plant growth. Depth matters—shallow topsoil means poor root development and struggling plants.

Ballast and Building Sand

Ballast for concrete:

• Shed bases: 100-150mm depth
• Driveway bases: 100-150mm depth
• Foundation footings: Varies by structural requirements

Building Sand for mortar:

• Bricklaying mortar: Mixed as needed (typically 3:1 or 4:1 sand:cement)
• Rendering: 10-15mm per coat
• Pointing: 10-20mm depth

MOT Type 2 and Shingle

MOT Type 2 (permeable sub-base):

• Permeable paving: 100-150mm depth
• Drainage layers: 75-100mm depth
• Light traffic areas: 75-100mm depth

10mm-20mm Shingle:

• Drainage systems: 50-100mm depth
• Decorative landscaping: 30-50mm depth
• Pipe bedding: 100-150mm around pipes

Quick Coverage Reference (Per Tonne)

Use these approximate coverage rates for quick estimating:

MOT Type 1:

• 1 tonne covers approximately 10m² at 50mm depth
• 1 tonne covers approximately 6.5m² at 100mm depth
• 1 tonne covers approximately 4.5m² at 150mm depth

Sharp Sand:

• 1 tonne covers approximately 11m² at 50mm depth
• 1 tonne covers approximately 5.5m² at 100mm depth

Topsoil:

• 1 tonne covers approximately 15m² at 50mm depth
• 1 tonne covers approximately 10m² at 75mm depth
• 1 tonne covers approximately 7m² at 100mm depth

Ballast:

• 1 tonne covers approximately 11m² at 50mm depth
• 1 tonne covers approximately 5.5m² at 100mm depth

Building Sand:

• 1 tonne covers approximately 12m² at 50mm depth
• 1 tonne covers approximately 6m² at 100mm depth

These are approximations. Exact coverage varies based on material moisture, compaction, and wastage.

Step-by-Step: How to Calculate Your Order

Step 1: Measure the Area

Use a tape measure. Record in metres.

For rectangular areas:

• Length × Width = Area in m²

For irregular shapes:

• Break into smaller rectangles
• Calculate each section separately
• Add them together

Example: L-shaped driveway

• Section 1: 8m × 4m = 32m²
• Section 2: 6m × 3m = 18m²
• Total: 50m²

Step 2: Determine the Depth

Choose based on application (see depths above).

Convert millimetres to metres by dividing by 1000:

• 150mm = 0.15m
• 100mm = 0.10m
• 75mm = 0.075m
• 50mm = 0.05m

Step 3: Calculate Volume

Area (m²) × Depth (m) = Volume (m³)

Example: 50m² driveway at 150mm depth

• 50 × 0.15 = 7.5m³

Step 4: Account for Compaction

For MOT Type 1, Type 2, and compacting materials:

Add 10-15% to your volume to account for compaction.

• 7.5m³ × 1.15 = 8.625m³ (adding 15% for compaction)

For sharp sand, topsoil, and ballast:

No significant compaction adjustment needed unless specifications require it.

Step 5: Convert to Tonnes

Volume (m³) × Material Density = Tonnes needed

Example: 8.625m³ of MOT Type 1

• 8.625 × 2.1 = 18.1 tonnes

Round up to 18.5 or 19 tonnes to account for wastage.

Step 6: Add Wastage Allowance

Always order 5-10% extra:

5% wastage: For simple, straightforward projects with accurate measurements 10% wastage: For complex shapes, difficult access, or if measurements aren't precise

Example: 18.1 tonnes + 10% = 19.9 tonnes

Order 20 tonnes to be safe.

Real Project Examples

Example 1: Driveway Sub-Base (MOT Type 1)

Project: New residential driveway Dimensions: 12m long × 3.5m wide
Required depth: 150mm (compacted)

Calculation:

1. Area: 12 × 3.5 = 42m²
2. Depth: 150mm = 0.15m
3. Volume: 42 × 0.15 = 6.3m³
4. Compaction: 6.3 × 1.15 = 7.25m³
5. Tonnes: 7.25 × 2.1 = 15.2 tonnes
6. Wastage: 15.2 × 1.1 = 16.7 tonnes

Order: 17 tonnes of MOT Type 1

Example 2: Patio Paving (Sharp Sand Bedding)

Project: Patio paving slabs Dimensions: 6m × 4m Required depth: 50mm bedding layer

Calculation:

1. Area: 6 × 4 = 24m²
2. Depth: 50mm = 0.05m
3. Volume: 24 × 0.05 = 1.2m³
4. Tonnes: 1.2 × 1.8 = 2.16 tonnes
5. Wastage: 2.16 × 1.1 = 2.4 tonnes

Order: 2.5 tonnes of Sharp Sand

Example 3: New Lawn (Topsoil for Turfing)

Project: New turf lawn Dimensions: 8m × 10m Required depth: 100mm topsoil

Calculation:

1. Area: 8 × 10 = 80m²
2. Depth: 100mm = 0.10m
3. Volume: 80 × 0.10 = 8m³
4. Tonnes: 8 × 1.5 = 12 tonnes (using mid-range density)
5. Wastage: 12 × 1.05 = 12.6 tonnes

Order: 13 tonnes of BS3882:2015 Topsoil

Example 4: Shed Base (Ballast for Concrete)

Project: Concrete shed base Dimensions: 3m × 4m Required depth: 100mm concrete

Calculation:

1. Area: 3 × 4 = 12m²
2. Depth: 100mm = 0.10m
3. Volume: 12 × 0.10 = 1.2m³
4. Tonnes: 1.2 × 1.75 = 2.1 tonnes of ballast
5. Plus cement: 6:1 ratio = 0.35 tonnes cement
6. Wastage: 2.1 × 1.1 = 2.3 tonnes ballast

Order: 2.5 tonnes of Ballast + 350kg cement

Common Calculation Mistakes (And How to Avoid Them)

Mistake #1: Measuring in Centimetres, Calculating in Metres

What happens: You measure 1500cm × 400cm, then calculate 1500 × 400 = 600,000m²

Clearly wrong, but it happens when you're rushing.

Fix: Always convert to metres first. 1500cm = 15m, 400cm = 4m. Then: 15 × 4 = 60m²

Mistake #2: Forgetting to Divide Millimetres by 1000

What happens: Area is 50m², depth is 150mm. Calculation: 50 × 150 = 7,500m³

You've just ordered material for 7,500 cubic metres instead of 7.5m³. That's a 15,750 tonne order instead of 15.75 tonnes.

Fix: Always convert mm to metres. 150mm ÷ 1000 = 0.15m

Mistake #3: Not Accounting for Compaction

What happens: You calculate 10m³ of MOT Type 1, order 21 tonnes (10 × 2.1), lay it, compact it. Final depth is 130mm instead of 150mm. Now you're short.

Fix: Add 10-15% to volume before converting to tonnes when using MOT Type 1 or Type 2. These materials compact significantly.

Mistake #4: Using Wrong Material Density

What happens: You need topsoil, use MOT Type 1 density (2.1 tonnes/m³) in your calculation. Order 21 tonnes for 10m³ of topsoil. Actually need only 15 tonnes. Overpaid by £200+.

Fix: Use correct density for each material. When in doubt, ask your account manager.

Mistake #5: No Wastage Allowance

What happens: Calculate perfectly: need exactly 12 tonnes. Order 12 tonnes. Site has uneven ground, edges need filling, bit of spillage. Run short by 1-1.5 tonnes.

Project stops. Emergency delivery costs £150 extra. Could've just ordered 13 tonnes initially.

Fix: Always add 5-10% wastage. Aggregates are cheap compared to wasted project time and emergency delivery charges.

Mistake #6: Ignoring Irregular Shapes

What happens: You've got an L-shaped area. You measure the longest length and widest width, multiply them. You've now calculated material for a rectangle that includes area you're not actually filling.

Fix: Break irregular shapes into multiple rectangles, calculate each separately, add them up.

Bulk vs Bagged: What to Order

WasteHub supplies aggregates by the tonne or in bags. Here's when to use each:

Bagged aggregates (850-1000kg bulk bags):

• Projects under 3-4 tonnes
• Restricted access sites
• Phased projects where you need material at different times
• When crane offload is available
• Situations where precise placement matters

Loose loads (tipped):

• Projects over 4-5 tonnes (more economical)
• Open site access
• When you can use grab hire for placement
• Large groundworks or base layers

Grab lorry delivery (up to 16 tonnes):

• Precise placement needed
• Difficult access but space to maneuver grab
• When tipping isn't practical

Tipper lorry delivery (up to 20 tonnes):

• Maximum load capacity
• Simple tip-and-spread applications
• Easy access for large vehicles

Minimum orders: We deliver from 1 tonne, but note that small loads may incur empty carriage fees. Best value is ordering in bulk when your project allows.

The Hidden Costs of Getting It Wrong

Scenario 1: Under-Ordering

You need 15 tonnes, calculate 12 tonnes, order 12 tonnes.

What happens:

• Project stops mid-way
• Emergency delivery needed: £80-150 surcharge
• Labour standing around waiting: £200-300 lost productivity
• Client unhappy with delay

Total extra cost: £280-450 for saving £100 on material

Scenario 2: Over-Ordering

You need 15 tonnes, panic-order 25 tonnes "to be safe"

What happens:

• 10 tonnes unused material
• Either: Pay for muckaway removal (£200-300), OR
• Material sits in yard unused, slowly degrading

Total wasted: £350-450 in unused material

Scenario 3: Wrong Material Ordered

You need MOT Type 1 for driveway base, order MOT Type 2 or Crushed Concrete instead.

What happens:

• Material doesn't compact properly
• Drainage issues or instability
• Either: Rip it out and start again (£500-1000+), OR
• Live with substandard base that fails in 1-2 years

The right calculation saves money. 5 minutes with the formula beats hours of project delay and hundreds in extra costs.

When Calculations Get Complex

Some projects need more than the basic formula:

Multi-layer applications:

• Driveway: MOT Type 1 sub-base (150mm) + Sharp Sand bedding (50mm) + paving
• Calculate each layer separately

Slopes and gradients:

• Depth varies across the site
• Calculate based on average depth, then add extra wastage (15%)

Excavation fill:

• Need to account for ground removed
• Volume of hole ≠ volume of fill (compaction reduces it)

Heavy-duty applications:

• Commercial vehicle access
• May need structural engineer calculations
• Standard depths might not apply

For complex jobs: Use the formula for rough estimate, then contact your WasteHub account manager. We've seen thousands of projects and know what actually works for your specific situation.

Delivery Options and Site Considerations

Once you've calculated how much you need, delivery method matters:

Grab lorry (up to 16 tonnes):

• Can place material precisely where needed
• Reaches over walls or obstacles
• Ideal for gardens, rear access, restricted sites
• Requires space for vehicle (grab arm extends 6-8m)

Tipper lorry (up to 20 tonnes):

• Maximum load capacity
• Material is tipped in one location
• Need wheelbarrow or machinery to move it around site
• Cheaper per tonne than grab delivery

Bulk bags (crane offload):

• Placed exactly where needed
• No spreading required
• Perfect for phased projects
• Can store bags for weeks if needed

Site access checklist:

• Ground strong enough for heavy vehicle (25-32 tonnes)
• Width sufficient (3m minimum for lorries)
• Height clearance (4m minimum for tippers, 5m for grabs)
• No overhead cables or tree branches
• Turning circle if vehicle needs to reverse out

Your account manager confirms delivery method based on your site access and material quantity.

Alternative Materials: When to Use What

Your calculation is correct, but are you using the right material?

Instead of MOT Type 1, consider:

MOT Type 2 - Permeable sub-base for SUDS compliance, better drainage Crushed Concrete - Recycled alternative, cheaper, eco-friendly, good for temporary roads

Instead of Sharp Sand, consider:

Building Sand - Better for mortar and bricklaying (finer texture)

For specialized applications:

Readymix Concrete - Large slabs or structural work (better than mixing ballast on-site) 10mm-20mm Shingle - Drainage systems, decorative landscaping

Not sure which material? Your WasteHub account manager advises based on your specific application. We've supplied 25+ years across thousands of projects—we know what works.

How WasteHub Helps You Get It Right

Here's the reality: You can use the formula above for a solid estimate. But material densities vary, site conditions differ, and application requirements change.

When you contact WasteHub, here's what happens:

1. You tell us the project: "10m × 5m driveway, need MOT Type 1 sub-base"
2. We ask the right questions:
   • What's going on top? (Affects depth requirement)
   • What's the existing ground like? (Affects compaction)
   • Vehicle access? (Car driveway vs commercial traffic)
3. We calculate exact tonnage: Based on real material density, proper depth for application, compaction factors, and wastage allowance
4. We recommend delivery method: Grab vs tipper vs bagged, based on your site access
5. We coordinate everything: One WhatsApp message, material ordered, delivery scheduled, sorted

No guesswork. No over-ordering. No running short.

You can calculate yourself using the formula in this guide—that gives you a solid ballpark figure. But for exact quantities and material recommendations, your account manager has done this thousands of times and knows what actually works.

The Bottom Line

Use this formula for any aggregate:

Length (m) × Width (m) × Depth (m) = Volume (m³)

Then:

1. Add 10-15% for compaction (MOT Type 1, Type 2)
2. Multiply by material density to get tonnes
3. Add 5-10% wastage allowance
4. Round up to nearest half-tonne

Standard depths:

• Driveways: 150mm MOT Type 1
• Patios: 100mm MOT Type 1 + 50mm Sharp Sand
• Paths: 75mm MOT Type 1
• Turfing: 100-150mm Topsoil

Coverage per tonne (approximate):

• MOT Type 1: 6.5m² at 100mm depth
• Sharp Sand: 11m² at 50mm depth
• Topsoil: 10m² at 75mm depth
• Ballast: 11m² at 50mm depth

For complex projects, unusual applications, or if you want exact quantities confirmed: Your WasteHub account manager does this calculation daily and knows the real-world factors that affect your specific job.

Get Your Aggregate Calculation Confirmed

Stop guessing at quantities. Give us your project dimensions and material type, we'll calculate exact tonnage and recommend the most cost-effective delivery method.

Full range of aggregates available - MOT Type 1, Type 2, Sharp Sand, Building Sand, Ballast, Topsoil, Shingle, Crushed Concrete.

Delivered in bulk bags or loose loads. Grab hire for precise placement. Same-day delivery available across London.

Whatsapp Us At 07949 088642 or call 0208 036 3575. Tell us your area dimensions and what you're building. We'll give you exact tonnage and delivery options in 10 minutes.