Use this free UK aggregate grading chart to compare sieve sizes, particle distribution, coarse/fine aggregate designations, ballast, MOT Type 1 and recycled sub-base materials for concrete, mortar, drainage and groundwork projects.
What Is Aggregate Grading?
Aggregate gradingis the particle size distribution of sand, gravel, crushed rock, recycled aggregate or sub-base material. In practice, it tells you how much material passes through each sieve size. A well-graded aggregate contains a balanced blend of large, medium and fine particles; a single-sized aggregate contains particles mostly within one narrow size band.
For UK concrete, aggregate selection is usually linked toBS EN 12620 and BS 8500. For unbound road and sub-base materials, the relevant family of standards is usuallyBS EN 13242. This page is a quick-reference chart for builders, guides and homeowners, not a replacement for the grading certificate supplied by a quarry, ready-mix producer or aggregate merchant.
2026 UK Standards Note
BS EN 12620 classifies concrete aggregates as natural, manufactured or recycled, while BS 8500:2023 is the UK complementary standard to BS EN 206 for concrete specification. Use this chart for early estimating and supplier comparisons, then confirm project-critical concrete aggregate grading with the producer’s declared grading.
Sieve Analysis
A sample is dried, weighed and passed through stacked sieves. The percentage retained and passing each sieve forms the grading curve used for QA and mix design.
Concrete Workability
Too many fines can increase water demand. Too much single-sized stone can make concrete harsh and difficult to compact around reinforcement.
Sub-base Compaction
Well-graded Type 1 and crusher-run materials compact into a locked structure. Open-graded clean stone drains better but compacts differently.
Aggregate Grading Curve — Visual Reference
A grading curve plots sieve size against percentage passing. A steep curve usually means the material is more single-sized. A smoother curve means the aggregate has a wider particle-size spread and can fill voids more efficiently.
Do Not Use Generic Charts for Final Specification
Two products with the same trade name can have different grading curves depending on quarry source, washing, crushing method and recycled content. For structural concrete, always specify by standard, grading category and supplier declaration rather than relying only on a web chart.
UK Aggregate Size Chart — Concrete, Sand, Ballast & Sub-base
The table below gives a practical UK reference for common aggregate descriptions used by builders’ merchants, ready-mix suppliers and groundwork contractors in 2026.
- Material Name: Concreting Sand / Sharp Sand; Typical Size / d/D: 0/4mm; Aggregate Category: Fine aggregate; Common UK Use: Concrete, screed, slab bedding, render blends; Important Note: Concrete fine aggregate
- Material Name: Building Sand; Typical Size / d/D: 0/2mm approx.; Aggregate Category: Fine aggregate; Common UK Use: Mortar, bricklaying, pointing; Important Note: Usually not for concrete
- Material Name: 10mm Gravel / Pea Gravel; Typical Size / d/D: 4/10mm; Aggregate Category: Small coarse aggregate; Common UK Use: Drainage, pipe bedding, thin concrete sections; Important Note: Check fines content
- Material Name: 20mm Stone / Gravel; Typical Size / d/D: 10/20mm or 4/20mm; Aggregate Category: Coarse aggregate; Common UK Use: Concrete slabs, foundations, domestic ready-mix; Important Note: Most common concrete stone
- Material Name: All-in Ballast; Typical Size / d/D: 0/20mm approx.; Aggregate Category: Combined fine + coarse; Common UK Use: Site-mixed concrete for non-critical domestic work; Important Note: Variable grading
- Material Name: MOT Type 1; Typical Size / d/D: 0/40mm approx.; Aggregate Category: Unbound sub-base; Common UK Use: Driveways, patios, paths, road sub-base; Important Note: Designed to compact
- Material Name: 6F2 / Crusher Run; Typical Size / d/D: 0/63mm or similar; Aggregate Category: Recycled / capping material; Common UK Use: Hardcore, temporary roads, bulk fill, capping; Important Note: Not concrete aggregate
Typical Percentage Passing Table
This reference table gives indicative percentage passing values for common material types. They are deliberately rounded and simplified so guides can compare shapes of grading curves quickly. For compliance, use a laboratory sieve analysis and the supplier’s stated grading category.
- Sieve Size: 40mm; 0/4 Sand: 100%; 4/10 Gravel: 100%; 10/20 Stone: 100%; 0/20 Ballast: 100%; 0/40 Type 1: 95–100%
- Sieve Size: 20mm; 0/4 Sand: 100%; 4/10 Gravel: 100%; 10/20 Stone: 95–100%; 0/20 Ballast: 95–100%; 0/40 Type 1: 70–90%
- Sieve Size: 10mm; 0/4 Sand: 100%; 4/10 Gravel: 85–100%; 10/20 Stone: 0–20%; 0/20 Ballast: 60–85%; 0/40 Type 1: 50–75%
- Sieve Size: 4mm; 0/4 Sand: 85–100%; 4/10 Gravel: 0–15%; 10/20 Stone: 0–5%; 0/20 Ballast: 35–60%; 0/40 Type 1: 35–60%
- Sieve Size: 2mm; 0/4 Sand: 65–95%; 4/10 Gravel: 0–5%; 10/20 Stone: 0–3%; 0/20 Ballast: 25–50%; 0/40 Type 1: 25–45%
- Sieve Size: 0.5mm; 0/4 Sand: 30–70%; 4/10 Gravel: 0–3%; 10/20 Stone: 0–2%; 0/20 Ballast: 10–30%; 0/40 Type 1: 10–30%
- Sieve Size: 0.063mm; 0/4 Sand: 0–10%; 4/10 Gravel: 0–2%; 10/20 Stone: 0–1.5%; 0/20 Ballast: 0–8%; 0/40 Type 1: 0–12%
Fines Content Matters
Very fine particles influence water demand, shrinkage, drainage, compaction and dust risk. For concrete, too many fines can affect workability and strength. For sub-base, fines help lock the material together but too many fines can hold water and make compaction unreliable.
Concrete Aggregate Grading vs Sub-base Grading
Concrete aggregate and sub-base aggregate are not specified for the same job. Concrete aggregates must contribute to workable, durable concrete around cement paste and reinforcement. Sub-base materials must compact into a stable layer that spreads load under driveways, slabs, roads and patios.
Concrete Aggregates
Usually specified under BS EN 12620 and used with BS 8500 concrete requirements. Includes fine aggregate and coarse aggregate such as 10mm or 20mm stone.
Unbound Sub-base
Usually linked to BS EN 13242 and highway specifications. Includes MOT Type 1, Type 3, 6F2 and recycled crusher-run materials.
Recycled Aggregates
Can be suitable for selected uses when properly processed and certified, but should not be assumed suitable for structural concrete without specification approval.
Concrete aggregate grading checklist
- Nominal size:Choose a maximum size that can pass through reinforcement and around formwork without honeycombing.
- Fine/coarse balance:Ensure the supplier’s mix design balances fine aggregate, coarse aggregate and paste content.
- Shape and flakiness:Angular crushed rock may improve interlock but can reduce workability compared with rounded gravel.
- Fines and dust:Check fines content and cleanliness, especially for washed concrete aggregate.
- Chloride and sulfate risk:Consider exposure class, ground conditions and chloride limits where durability matters.
Sub-base grading checklist
- Layer thickness:Use enough compacted depth for the expected traffic and ground conditions.
- Compaction:Lay in layers and compact each layer with a suitable plate compactor or roller.
- Drainage:Avoid trapping water under slabs and paved areas; consider falls, geotextiles and drainage stone where needed.
- Contamination:Recycled hardcore should be free from excessive wood, plaster, clay, metal and deleterious material.
- Supplier declaration:Ask for the product type, grading and compliance statement on commercial projects.
How to Read a Sieve Analysis Report
A sieve analysis report normally lists sieve sizes in millimetres and the percentage retained or passing. The most useful number for a grading chart ispercentage passing, because it shows how much of the sample is smaller than each sieve opening. A material with 100% passing the 20mm sieve and 5% passing the 4mm sieve is mostly coarse 20mm stone. A material with 100% passing 4mm and a broad spread through smaller sieves is fine aggregate.
Common UK Aggregate Names Explained
Trade names can be confusing because merchants often use friendly names while standards use d/D sizes and compliance categories. Use the descriptions below to avoid ordering the wrong material.
Sharp Sand
Coarser than building sand and often used for concrete, screed and slab bedding. Check whether it is washed and suitable for the intended use.
Building Sand
Finer, softer sand for bricklaying mortar. It is not normally the best aggregate for concrete because the particle grading and clay/fines content may be unsuitable.
Ballast
A combined sand-and-stone material commonly sold for site-mixed concrete. Convenient for small jobs but grading can vary by source.
20mm Gravel
A common coarse aggregate for slabs, foundations and ready-mix concrete. It may be rounded gravel or crushed rock, depending on supplier.
MOT Type 1
A compactable sub-base material used under driveways, patios, paths and hardstandings. It is not the same as concrete aggregate.
6F2
A recycled bulk fill or capping material often used for temporary roads and hardcore layers. It is generally too coarse/variable for concrete.
Control Silica Dust When Handling Aggregates
Sand, stone, concrete and many aggregate products can produce respirable crystalline silica dust when cut, crushed, swept dry or tipped. Use water suppression, extraction, good housekeeping and suitable respiratory protection where required by risk assessment.
Related ConcreteMaths Resources
Use this aggregate grading chart with our other UK guides and reference pages to estimate quantities, convert volumes and choose suitable concrete materials.
- Concrete Slab Guide UKwork out concrete volume, bags, sub-base and materials.
- Cubic Metres to Tonnes conversion guideconvert m³ of sand, gravel, aggregate or concrete into tonnes.
- Sharp Sand Guideestimate sand volume, weight and bags.
- Material Quantity Tablesquick UK reference for concrete, mortar, sand, ballast and cement.
- Material Suppliers Comparison UKcompare merchants, quarry suppliers and delivery options.
Aggregate Grading Chart — FAQs
Common questions about UK aggregate sizes, grading curves, sieve analysis and material selection in 2026.