Weight, Volume, Coverage & Cost for Stone, Gravel, MOT Type 1 & Aggregates — UK 2026
Crushed stone and aggregates are among the most widely used construction materials in the UK, from structural sub-base beneath driveways and paved areas to decorative gravel in gardens and landscaping. Understanding how to calculate the right quantity — and choosing the right stone type — is essential for accurate budgeting and avoiding the cost and inconvenience of either running short or significantly over-ordering.
Stone is sold by weight in the UK, always in tonnes. Unlike concrete — which is ordered by volume in cubic metres — aggregate is priced and delivered by the tonne, and the conversion from the volume or area you need to cover into the number of tonnes to order depends on the bulk density of the specific stone type. This calculator performs that conversion automatically, using established bulk density values for each aggregate type.
The key measurement concepts for buying crushed stone correctly are bulk density, compaction factor, and wastage. Bulk density is the weight of stone per unit of loose volume — typically expressed in tonnes per cubic metre (t/m³). MOT Type 1 has a bulk density of approximately 1.50–1.60 t/m³, meaning one cubic metre of loose-tipped MOT Type 1 weighs approximately 1.55 tonnes. Lighter decorative stones like slate chippings have a lower bulk density (~1.35–1.45 t/m³), so a tonne of slate goes further by volume than a tonne of granite.
Compaction factor matters when specifying a compacted layer depth. When MOT Type 1 is loose-tipped, it occupies more volume than after compaction — compaction typically reduces the loose volume by 10–15%. This means you need to order slightly more stone than the target compacted volume implies. The calculator applies the loose bulk density, which naturally accounts for this: the tonnes calculated will deliver the correct compacted depth after proper vibrating plate compaction.
MOT Type 1 (Specification for Highway Works Clause 804) is the standard specification for granular sub-base material in UK construction. It is a graded crushed rock — typically limestone, granite, or gritstone — with particle sizes from 0 to 37.5mm, compacted to a tight specification achieving minimum CBR values of 30% or greater. MOT Type 1 is the required sub-base for driveways, patios, paths, and most external paved areas under building control requirements across the UK.
The standard specification for a domestic driveway is: 100–150mm compacted MOT Type 1 sub-base (200mm for heavy vehicle use), followed by the paving layer — either 50mm compacted sharp sand and block paving, or direct concrete. For a loose gravel driveway, the MOT Type 1 sub-base is followed by approximately 50mm of surface gravel retained by an edge restraint system.
Driveways (sub-base): MOT Type 1 at 150mm compacted depth under block paving or concrete; 100mm for pedestrian paths. Recycled crushed concrete (RCC) is a lower-cost alternative accepted by most building control authorities for domestic applications.
Driveways (loose gravel surface): 20mm clean crushed limestone, hoggin (self-binding gravel), or 10–20mm shingle at 50mm depth on MOT Type 1 sub-base with edge restraints. Hoggin is preferred for permeable driveways as it self-compacts and does not track as badly as loose rounded gravel.
Garden paths and landscaping: Decorative aggregates — slate chippings, Cotswold chippings, pea gravel, flint gravel, and shingle — at 40–50mm depth on weed-control membrane. Deeper than 75mm is unnecessary; shallower than 40mm leaves ground visible through the membrane.
Drainage: 20mm clean single-size crushed limestone or washed pea gravel for French drains, soakaways, and pipe bedding. Single-size clean stone is essential — do not use MOT Type 1 (which contains fines) for drainage as it will block drainage flow over time.
Aggregate Resources 2026: Specification for Highway Works at Standards for Highways | Aggregate Industries at Aggregate Industries UK | Breedon Group at Breedon Group | Hanson at Hanson UK | NHBC at NHBC
| Stone / Aggregate Type | Loose Bulk Density (t/m³) | Compacted Density (t/m³) | Typical Layer Depth | 2026 Price (£/tonne supply-only) | Primary Use |
|---|---|---|---|---|---|
| MOT Type 1 Sub-base | 1.50–1.60 | 1.75–1.90 | 100–150mm compacted | £28–£42 | Driveway / paving sub-base — UK standard |
| MOT Type 2 / Scalping / Crusher Run | 1.45–1.55 | 1.70–1.85 | 75–150mm compacted | £22–£38 | Sub-base, access tracks, fill |
| Crushed Limestone 20mm | 1.35–1.45 | 1.60–1.75 | 50–100mm | £32–£48 | Drainage, soakaways, French drains, concrete aggregate |
| Crushed Granite 20mm | 1.45–1.55 | 1.70–1.85 | 50–100mm | £38–£55 | Sub-base, drainage, concrete aggregate |
| Crushed Basalt 20mm | 1.50–1.60 | 1.75–1.92 | 50–100mm | £40–£58 | High-strength concrete, road construction |
| Recycled Crushed Concrete (RCC) | 1.25–1.40 | 1.50–1.70 | 75–150mm compacted | £18–£32 | Sub-base alternative, fill — check with building control |
| Pea Gravel 10–14mm | 1.45–1.60 | 1.68–1.80 | 40–75mm | £35–£55 | Drainage, pipe bedding, garden paths |
| Single Size Gravel 20mm | 1.45–1.58 | 1.68–1.82 | 50–75mm | £32–£52 | Soakaways, drainage channels, garden paths |
| Hoggin (Self-binding Gravel) | 1.55–1.75 | 1.85–2.10 | 75–150mm | £28–£48 | Rural driveways, paths, horse arenas |
| Ballast / All-in Aggregate | 1.55–1.70 | 1.80–2.00 | — | £28–£45 | On-site concrete batching (1:5 cement:ballast) |
| Shingle 10–20mm (Beach/River) | 1.50–1.62 | 1.72–1.88 | 40–75mm | £38–£62 | Decorative garden paths, borders, drainage |
| Grit — 6mm Fine Crushed Stone | 1.40–1.55 | 1.65–1.80 | 25–50mm | £38–£58 | Garden paths, play areas, surface dressing |
| Slate Chippings 20–40mm | 1.30–1.45 | 1.50–1.68 | 40–75mm | £55–£95 | Decorative garden borders, paths, low maintenance |
| Cotswold Chippings (Golden Gravel) | 1.35–1.50 | 1.55–1.72 | 40–75mm | £62–£110 | Decorative garden paths, driveways, borders |
| Flint Gravel 20mm | 1.48–1.62 | 1.70–1.85 | 40–75mm | £45–£78 | Decorative garden, paths, coastal landscaping |
All density values are approximate. Actual values vary by source quarry, particle size, shape, and moisture content. Always add a minimum 10% wastage to calculated quantities. Prices are UK supply-only trade estimates for May 2026 — delivery adds £75–£180 per tipper load (up to 20t).
| Stone Type | At 25mm depth (m²/t) | At 50mm depth (m²/t) | At 75mm depth (m²/t) | At 100mm depth (m²/t) | At 150mm depth (m²/t) |
|---|---|---|---|---|---|
| MOT Type 1 | 25–27 m²/t | 12–14 m²/t | 8–9 m²/t | 6–7 m²/t | 4–4.5 m²/t |
| Crushed Limestone 20mm | 27–30 m²/t | 14–15 m²/t | 9–10 m²/t | 7–7.5 m²/t | 4.5–5 m²/t |
| Crushed Granite 20mm | 25–27 m²/t | 12–14 m²/t | 8–9 m²/t | 6–7 m²/t | 4–4.5 m²/t |
| Pea Gravel / Shingle | 25–28 m²/t | 12–14 m²/t | 8–9 m²/t | 6–7 m²/t | 4–4.5 m²/t |
| Hoggin (self-binding) | 22–24 m²/t | 11–12 m²/t | 7–8 m²/t | 5.5–6.5 m²/t | 3.5–4 m²/t |
| Slate Chippings | 27–30 m²/t | 14–15 m²/t | 9–10 m²/t | 7–8 m²/t | 4.5–5 m²/t |
| Cotswold Chippings | 26–30 m²/t | 13–15 m²/t | 9–10 m²/t | 6.5–7.5 m²/t | 4–5 m²/t |
| Recycled Crushed Concrete | 28–32 m²/t | 14–16 m²/t | 9–11 m²/t | 7–8 m²/t | 4.5–5.5 m²/t |
Values shown are for loose-placed material. Compacted sub-base (MOT Type 1, hoggin) requires approximately 10–15% more stone than these loose-volume equivalents. Always add 10% wastage to your calculated order quantity.
All aggregate is sold in tonnes in the UK — not in cubic metres. The conversion from the volume or area you need to fill into the tonnage to order depends on the bulk density of the specific stone type. MOT Type 1 at 1.55 t/m³ and slate chippings at 1.38 t/m³ cover very different areas per tonne — always use the density-based calculation rather than a generic rule of thumb.
At a loose bulk density of approximately 1.55 t/m³, one tonne of MOT Type 1 occupies approximately 0.65 m³ when loose-tipped from a tipper truck. After vibrating plate compaction, this shrinks to approximately 0.55 m³. For planning: 1 m³ of loose MOT Type 1 ≈ 1.55 tonnes to order.
When specifying a compacted layer depth, you must order more loose material than the target compacted depth implies. Compaction typically reduces the loose volume by 10–15%. This calculator applies the loose bulk density and automatically gives you the correct tonnes to order for your target compacted depth.
MOT Type 1 (SHW Clause 804) is required under driveways, patios, and paved areas in UK building control guidance. Minimum 100mm compacted for pedestrian paving; 150mm for domestic vehicle driveways; 200mm for heavy vehicles. Always compact in maximum 150mm loose layers with a vibrating plate compactor.
A typical 8-wheel tipper truck carries 14–20 tonnes of aggregate. For MOT Type 1 at 1.55 t/m³, a 20-tonne tipper is approximately 12.9 m³ loose. Tipper delivery is significantly more economical than bulk bags for quantities above approximately 4–5 tonnes — typically 30–50% lower cost per tonne.
Decorative aggregates for garden borders and paths are typically laid at 40–50mm depth on weed-control membrane. Below 40mm, ground may show through. A 50mm layer on 10 m² requires approximately 0.75–0.80 tonnes of most decorative aggregates. Always lay on a good-quality permeable weed-control membrane.
Recycled crushed concrete (RCC) at £18–£32/t is the most economical sub-base aggregate in 2026 — approximately 25–40% cheaper than virgin MOT Type 1. Accepted by most building control authorities for domestic driveway sub-bases. Confirm suitability with your local authority before use on adopted highway or commercial specifications.
For drainage applications — French drains, soakaways, pipe bedding — always specify single-size clean stone with no fines (20mm clean crushed limestone or pea gravel). Never use MOT Type 1 or ballast for drainage — the fine content clogs drainage pathways within a few years.
Hoggin (self-binding gravel) is a natural mix of gravel, sand, and clay that binds when compacted. Popular for rural driveways, path networks, and horse arenas. Lay at 75–100mm compacted depth on MOT Type 1. Requires edge restraints. Permeable gravel driveways do not require planning permission for front gardens in England.
Slate chippings and flat decorative aggregates do not compact significantly under foot, making them excellent for low-maintenance garden paths and borders. Their irregular shape locks together loosely, reducing migration compared to rounded pea gravel. Welsh blue-grey and green slate are most popular in 2026.
Always lay a permeable weed-control membrane under decorative aggregates before placing stone. Without a membrane, weeds establish in fine organic matter between stones within 2–3 seasons. Use a good-quality 90–150 g/m² woven membrane, overlap joins by 150mm, and secure with ground pegs at 500mm centres.
Ballast (all-in aggregate, ~60% sharp sand and 40% 20mm stone) is used for small on-site concrete batching. A GEN3-equivalent concrete mix uses approximately 1 part cement to 5 parts ballast by weight. One tonne of ballast + 200 kg cement + water yields approximately 0.6 m³ of concrete — suitable for small pours under 0.5 m³.
Using MOT Type 1 at a loose bulk density of approximately 1.55 t/m³: Volume = 50 m² × 0.150 m = 7.5 m³. Weight = 7.5 × 1.55 = 11.6 tonnes. Adding 10% wastage: order approximately 12.8 tonnes. This is typically one standard 14-tonne tipper load. If you are adding a 50mm decorative surface gravel layer on top, add a further 50 × 0.050 × 1.50 ≈ 3.75 tonnes of surface stone.
MOT Type 1 (SHW Clause 804) is crushed angular rock graded 0–37.5mm to a tight specification with maximum 10% fines and minimum CBR of 30% when compacted. It must be entirely composed of hard, crushed material. MOT Type 2 (Clause 805) is less stringent — it allows rounded or naturally occurring particles and higher fines content, achieving a lower CBR. For driveways, paving sub-bases, and building control-approved applications, MOT Type 1 is specified. MOT Type 2 is acceptable for fill, access tracks, and non-critical sub-base where no structural performance specification is required.
For a path 10m × 1.0m wide at 50mm depth using 20mm gravel (density ~1.52 t/m³): Volume = 10 × 1.0 × 0.050 = 0.5 m³. Weight = 0.5 × 1.52 = 0.76 tonnes + 10% wastage = 0.84 tonnes. At approximately 850 kg per bulk bag: 0.84 ÷ 0.85 = 0.99 bags — round up to 1 bulk bag. One bulk bag typically covers 12–14 linear metres of standard 1.0m-wide garden path at 50mm depth.
Divide the weight in tonnes by the bulk density of the stone: Volume (m³) = Weight (t) ÷ Bulk Density (t/m³). Example: 5 tonnes of MOT Type 1 (density 1.55 t/m³) = 5 ÷ 1.55 = 3.23 m³. For crushed limestone (density 1.40 t/m³): 5 ÷ 1.40 = 3.57 m³. The density reference table on this page provides bulk densities for all common stone types. Treat results as approximate ±10% — actual density varies by source quarry, moisture content, and grading.
The standard UK specification for a domestic block-paved driveway is: 150mm compacted MOT Type 1 sub-base, followed by 50mm compacted sharp sand bedding, then the block pavers. For heavier loading (vans, 4x4s, motorhomes), increase the sub-base to 200–250mm compacted. For pedestrian patios and paths, 100mm compacted is sufficient. Always compact the MOT Type 1 in maximum 150mm loose layers using a vibrating plate compactor — compacting deeper in a single pass will not achieve adequate density and the surface will settle unevenly.
Yes, in many cases. Recycled crushed concrete (RCC) meets SHW Clause 803 for Type 3 material and is widely accepted by building control for domestic driveway sub-bases and garden paths. At £18–£32/t versus £28–£42/t for virgin MOT Type 1, the saving is approximately 25–40% on material cost. RCC has a slightly lower density (1.25–1.40 t/m³) and less predictable CBR than virgin material. Always confirm with your local authority building control before substituting RCC for MOT Type 1, particularly if the driveway or paving will be adopted as highway.
Stone is sold by weight because weight is precise and consistent — it is measured on a calibrated weigh bridge when the vehicle is loaded, and does not change with how the stone settles or packs. Volume is ambiguous: the same 5 tonnes occupies different volumes depending on how loosely or tightly it is packed. The practical workflow is: calculate the volume your project needs (length × width × depth), apply the bulk density to convert to weight, add wastage, and order in tonnes. This calculator handles all these steps automatically for each stone type.
In 2026, recycled crushed concrete (RCC) at approximately £18–£32 per tonne supply-only is the cheapest sub-base aggregate — followed by MOT Type 2 scalping at £22–£38/t and MOT Type 1 at £28–£42/t. For projects requiring virgin material (adopted highways, commercial specifications), MOT Type 1 from a certified supplier is the minimum acceptable material. Always compare total delivered cost rather than just supply price — delivery adds £75–£180 per tipper load regardless of stone type, which significantly changes the cost-per-m³ picture for small orders.
For a standard loose gravel driveway — 150mm compacted MOT Type 1 sub-base plus 50mm of 20mm clean gravel surface — the material cost in 2026 is approximately: Sub-base at 1.55 t/m³ × 0.150m × £35/t = £8.15/m². Surface gravel at 1.45 t/m³ × 0.050m × £42/t = £3.05/m². Total stone material: approximately £11–£12 per m² before delivery, edging, or membrane. For Cotswold chippings as the surface at £85/t, the surface layer alone adds £6–£7/m², giving approximately £14–£16/m² in materials.
In England, permeable gravel driveways where natural loose gravel on a free-draining sub-base allows rainwater to soak through are permitted development for front gardens and do not require planning permission. This is because they do not create surface water run-off onto the highway. For Scotland, Wales, and Northern Ireland, equivalent permitted development rules apply. However, creating a new vehicle crossing onto a public highway (dropped kerb) always requires separate consent from the local highway authority, regardless of driveway surface material.
The practical tipping point is approximately 4–5 tonnes. Below 4 tonnes, bulk bags (£45–£75 per bag including delivery for most standard aggregates) are more economical and practical — they can be positioned precisely on your property and you avoid the need to handle a large loose heap. Above 5 tonnes, tipper delivery is significantly cheaper: a 14-tonne tipper at £35/t + £120 delivery costs approximately £610 total (£43.5/t all-in), versus the same stone in bulk bags at £65/bag × 17 bags = £1,105 (£78.9/t all-in). For anything above 6m³ of stone, always compare both a tipper quote and bulk bags on total delivered cost.
Aggregate Resources 2026: Specification for Highway Works at Standards for Highways | Aggregate Industries at Aggregate Industries UK | Breedon Group at Breedon Group | Hanson at Hanson UK | Planning guidance at Planning Portal UK | NHBC at NHBC
© 2026 Crushed Stone Calculator UK. All quantities are estimates — actual requirements vary by site conditions, compaction method, and material variability. Always add a minimum 10% wastage to calculated quantities. Prices are indicative May 2026 supply-only trade estimates. Always obtain quotes from local aggregate suppliers.