How Much Gravel
Do I Need?
Free UK calculator for driveways, paths, and gardens. Get tonnage, bags, cost estimates, and a visual breakdown — instantly.
What are you covering?
Dimensions
How to Calculate Gravel by Hand
Our calculator does this instantly, but here's the maths if you want to double-check or work it out on paper.
The Formula
- 1
Calculate area
Length (m) × Width (m) = Area (m²)
- 2
Convert depth to metres
Depth (cm) ÷ 100 = Depth (m)
- 3
Calculate volume
Area (m²) × Depth (m) = Volume (m³)
- 4
Calculate weight
Volume (m³) × Density (kg/m³) = Weight (kg)
Common densities
- Gravel / Slate Gravel1,500 kg/m³
- Pebbles / Cobbles1,800 kg/m³
- MOT Type 1 (sub-base)2,000 kg/m³
Worked Example
A typical UK driveway: 5 m long × 3 m wide, filled to 5 cm depthwith standard gravel (1,500 kg/m³).
You would need
1.13 tonnes
≈ 57 × 20 kg bags or 2 × 500 kg bulk bags
For irregular shapes, split the area into rectangles and add the results. Our multi-area calculator handles this automatically.
Gravel Density Reference
Density determines how much a given volume of gravel weighs. Use the table below to find the right value for your material, or let our calculator handle it automatically.
| Gravel Type | Density (kg/m³) | Typical Size | Best For |
|---|---|---|---|
| Slate Gravel | 1,500 | 20–40mm | Driveways, decorative |
| Golden Gravel | 1,600 | 10–20mm | Driveways, paths |
| Cotswold Buff | 1,500 | 10–20mm | Paths, decorative |
| Pea Gravel | 1,550 | 6–10mm | Paths, play areas |
| Grey Granite | 1,600 | 14–20mm | Driveways, modern gardens |
| Plum Slate | 1,500 | 20–40mm | Feature areas |
| Polar Ice | 1,500 | 10–20mm | Contemporary gardens |
| Limestone | 1,500 | 10–20mm | Paths, borders |
| Pebbles / Cobbles | 1,800 | 30–80mm | Decorative, borders |
| Self-Binding Gravel | 1,700 | 0–14mm | Paths, wheelchair access |
| MOT Type 1 | 2,000 | 0–40mm | Sub-base |
All densities are approximate and may vary by supplier. UK-specific types like Cotswold Buff and Plum Slate are included — something you won't find on US calculator sites.
Coverage at a Glance
How much area does one tonne of gravel cover? It depends on the depth. This table gives quick estimates based on an average density of 1,500 kg/m³.
| Depth | Coverage per Tonne (approx.) |
|---|---|
| 30mm | ~22 m² |
| 40mm | ~17 m² |
| 50mm | ~13 m² |
| 60mm | ~11 m² |
| 75mm | ~9 m² |
| 100mm | ~7 m² |
Based on average gravel density of 1,500 kg/m³. Heavier materials (e.g. granite at 1,600 kg/m³) cover slightly less area per tonne.
Example Calculations
Real UK project sizes to help you estimate before you measure. All calculations use metric units and account for typical gravel densities.
Small Driveway (4m × 6m)
- Depth
- 50mm
- Gravel
- 20mm Slate Gravel
- Volume
- 1.2 m³
- Weight
- 1.8 tonnes
- Order
- ~2 bulk bags (1,000 kg)
Density: 1,500 kg/m³
Garden Path (10m × 1m)
- Depth
- 30mm
- Gravel
- 10mm Pea Gravel
- Volume
- 0.3 m³
- Weight
- 0.47 tonnes
- Order
- ~24 × 20 kg bags
Density: 1,550 kg/m³
Decorative Border (8m × 2m)
- Depth
- 40mm
- Gravel
- Plum Slate
- Volume
- 0.64 m³
- Weight
- 0.96 tonnes
- Order
- ~1 bulk bag (1,000 kg)
Density: 1,500 kg/m³
Why Choose Gravel?
No Planning Permission
Gravel is permeable, so no planning permission needed under UK rules (unlike tarmac or concrete over 5m²). With SuDS regulations tightening since January 2025, permeable surfaces like gravel are increasingly the smart choice.
Lowest Carbon Footprint
Gravel produces roughly 0.005–0.01 kg CO₂ per kg of material, compared to 0.4–0.5 for concrete and 0.48 for tarmac. It's the most environmentally friendly driveway and garden surface option.
Year-Round Savings
Buy in autumn/winter for 10–15% savings. Proximity to UK quarry regions (Derbyshire, Somerset, Leicestershire) means even lower transport costs. Delivery is often the biggest hidden cost — order in bulk to reduce per-tonne delivery charges.
Free Tools
Calculators and converters for your gravel project
Guides & Resources
Everything you need to plan, price, and install your gravel project
Driveway Cost Guide
Complete 2026 cost breakdown per m² — DIY vs professional, hidden costs, and price comparisons
How to Lay Gravel
Step-by-step guide from excavation to finished surface — driveways, paths, and gardens
Gravel vs Alternatives
Gravel vs resin vs tarmac vs block paving — cost, lifespan, and drainage compared
Planning Permission
The 5m² rule, SuDS 2025 changes, dropped kerbs, and when you don't need permission
Best Gravel for Driveways
Angular vs rounded, popular UK types, sizes, and colour guide
Stop Gravel Spreading
7 proven containment methods including edging, gravel grids, and stone selection
Maintenance Guide
Seasonal schedule, weed control, top-ups, and common repairs
Gravel on a Slope
Gradient limits, retention grids, and techniques to stop gravel sliding
Cat-Proof Gravel
Stop cats using your gravel — stone selection and deterrent methods that work
Gravel vs Bark Mulch
Cost, lifespan, maintenance, and which is better for borders
Wheelchair-Friendly Gravel
Gravel grids, self-binding gravel, and accessible surface design
Frequently Asked Questions
How much gravel do I need for a driveway?
How deep should gravel be?
How do I calculate how much gravel I need?
How many bags of gravel do I need?
What is the cheapest way to buy gravel in the UK?
Do I need a weed membrane under gravel?
What type of gravel is best for driveways?
How much does gravel cost in the UK?
Do I need planning permission for a gravel driveway?
When is the best time to buy gravel in the UK?
Do I need a sub-base under gravel?
Ready to buy your gravel?
Browse the full range at Stones4Gardens — quality aggregates delivered across the UK.