Concrete Grades Comparison | ConcreteMaths.com

Complete UK strength guide for C10 to C50 concrete grades, BS EN 206 class names, cube strength, cylinder strength, driveway mixes, slab mixes, foundations, reinforced concrete and practical ordering in 2026.

Choose a common UK concrete grade to see its practical use, typical official strength class, strength level and ordering note. This selector is for quick comparison only; final specification should follow the project drawings, engineer, Building Control, supplier advice and the exposure class.

Low Strength

Check spec

Strength Grade Is Only One Part of Concrete Specification

A higher grade is not automatically the right choice. UK concrete specification should also consider exposure class, cement type, aggregate size, workability, chloride class, reinforcement, cover, finish, placing method and curing. For standards background, seeThe Concrete CentreandBSI BS 8500.

Common UK Grade: C10; Typical BS EN 206 Style Class: C8/10 or supplier equivalent; Strength Level: Low; Common UK Uses: Blinding, bedding, mass fill, kerb backing, non-structural layers.; Ordering Notes: Useful where a clean working layer is needed but structural strength is not the main requirement.
Common UK Grade: C15; Typical BS EN 206 Style Class: C12/15 or C15/20 equivalent; Strength Level: Light duty; Common UK Uses: Light paths, small shed bases, domestic kerbs, drainage haunching and simple pads.; Ordering Notes: Check if freeze-thaw, vehicles, reinforcement or ground loading makes C20 or C25 more suitable.
Common UK Grade: C20; Typical BS EN 206 Style Class: C16/20 or C20/25 equivalent; Strength Level: General; Common UK Uses: Domestic slabs, garage bases, internal floors, oversite, some strip footings.; Ordering Notes: Popular for domestic work, but not enough for every driveway or structural requirement.
Common UK Grade: C25; Typical BS EN 206 Style Class: C20/25 or C25/30 equivalent; Strength Level: Medium; Common UK Uses: Driveways, reinforced domestic slabs, foundations, garage floors and external paving.; Ordering Notes: Often a practical minimum for driveways, but exposure and load still matter.
Common UK Grade: C30; Typical BS EN 206 Style Class: C25/30 or C30/37 equivalent; Strength Level: Strong; Common UK Uses: Heavy driveways, commercial slabs, agricultural yards, reinforced work and roads.; Ordering Notes: A common upgrade where vehicle loading, abrasion or durability requirements are higher.
Common UK Grade: C35; Typical BS EN 206 Style Class: C28/35 or C35/45 equivalent; Strength Level: Structural; Common UK Uses: Structural slabs, retaining walls, columns, beams, pile caps and suspended slabs.; Ordering Notes: Usually engineer-specified. Reinforcement detailing and cover are critical.
Common UK Grade: C40; Typical BS EN 206 Style Class: C32/40 or C40/50 equivalent; Strength Level: High; Common UK Uses: Industrial floors, high strength structural elements, precast units, heavy-duty pavements.; Ordering Notes: Requires proper placing, compaction, finishing and curing to achieve performance.
Common UK Grade: C45; Typical BS EN 206 Style Class: C35/45 or C45/55 equivalent; Strength Level: Very high; Common UK Uses: Engineered structural concrete, high load areas, durability-driven specifications.; Ordering Notes: Not normally a DIY grade. Confirm class, consistence and site procedure with the specifier.
Common UK Grade: C50; Typical BS EN 206 Style Class: C40/50 or C50/60 equivalent; Strength Level: Specialist; Common UK Uses: Specialist structural work, high-performance concrete, precast and demanding projects.; Ordering Notes: Needs controlled supply, quality assurance, curing and sometimes specialist admixtures.

Important: UK suppliers often use practical shorthand such as C20, C25 and C30. Formal BS EN 206 strength classes are written in cylinder/cube format such as C25/30. Always confirm the exact class and mix designation with your supplier or engineer.

Concrete Grades Explained for UK Projects in 2026

Concrete grade is a shorthand way of describing the compressive strength of hardened concrete. In simple site language, people often say C10, C20, C25, C30 or C40. In formal BS EN 206 language, the class is normally written with two numbers, such as C25/30 or C30/37. The first number is the characteristic cylinder strength in megapascals, and the second number is the characteristic cube strength, both measured at 28 days under standard test conditions. This is why a supplier, engineer or specification document may use a slightly different name from a builder’s everyday term, even when everyone is talking about the same broad strength band.

The aim of this guide is to make those names easier to understand for UK homeowners, tradespeople, site managers, small builders and self-builders. It compares common grades from C10 to C50, explains what they are normally used for, and shows how strength sits alongside practical factors such as exposure, workability, reinforcement, truck access, pumpability, finishing and curing. It is written for 2026 because UK concrete buyers are more cost-conscious than ever, but the technical principle has not changed: ordering the cheapest concrete can be expensive if it is the wrong grade, while ordering unnecessarily high strength can waste money and make finishing more difficult.

For domestic work, the grade decision is often linked to the job type. A light shed base is different from a driveway. A driveway for one car is different from a shared access route used by delivery vans. A strip footing for a garden wall is different from a trench-fill foundation for a building. A reinforced suspended slab is different from a plain ground-bearing slab. The grade must match the load, the exposure and the specification. That is why a concrete grades comparison page should never be treated as a replacement for engineering design, but it is a very useful first filter before you speak to a ready-mix supplier.

What the “C” number means

The letter C stands for concrete. The number that follows relates to compressive strength, commonly expressed in N/mm² or MPa. These units are effectively equivalent for this purpose: 1 N/mm² equals 1 MPa. A higher number means the concrete is expected to resist a higher compressive load at the standard testing age. However, strength is not the only measure of performance. A concrete grade can still fail in service if it is placed badly, cured badly, exposed to freezing and de-icing salts without the right specification, or used over poor sub-base preparation.

BS EN 206 is the key European concrete specification standard used in the UK framework, while BS 8500 provides the complementary British guidance and provisions for UK conditions. In practice, this means a proper concrete order may include more than just “C30”. It may include the exact strength class, consistence class, aggregate size, chloride class, exposure class, cement or combination type, designated mix reference or prescribed mix details. For many small domestic jobs, your supplier may simplify this into a named mix, but you should still understand what the chosen grade is expected to do.

C10, C15 and C20 Concrete — Light to General Domestic Grades

C10 Concrete

C10 is a low-strength concrete commonly used for blinding, mass fill, trench bedding, kerb backing and non-structural support layers. It creates a clean, level working surface and can separate reinforcement or structural concrete from soil. It should not be chosen for loaded slabs, driveways or structural members unless a competent specification says it is suitable.

C15 Concrete

C15 is a light-duty grade used for small bases, paths, light domestic pads and simple external works. It sits above basic blinding concrete but below the usual strength selected for heavier domestic slabs and vehicle areas. It is economical, but it should be upgraded where there is traffic, frost risk, poor ground or a more demanding finish.

C20 Concrete

C20 is one of the most familiar general-purpose domestic concrete grades. It is often used for internal slabs, garage bases, oversite concrete, paths, patios and some strip footings. It can be a practical choice where loading is modest, but it is not automatically the right answer for every driveway or engineered foundation.

Many UK customers search for “C20 concrete uses” because it is seen as the standard domestic grade. That is partly true, but it needs context. C20 may work well for a light ground-bearing slab if the ground is prepared, the sub-base is compacted, the depth is correct and curing is managed. But the same C20 concrete may be a poor choice for a thin external slab exposed to winter frost, poor drainage, moving vehicles and no joints. In 2026, with labour and delivery costs high, it is better to spend time choosing the right grade before the lorry is booked than to repair a cracked or spalled slab later.

For footings, C20 is sometimes used in domestic construction, but the specification should come from the drawings, Building Control, warranty provider or engineer. Soil type, trench width, depth, tree proximity, groundwater, sulphates and structural loads can all change the required concrete. If you are pouring foundations for an extension, do not rely only on a grade chart. Use the grade chart to understand the language, then follow the approved specification exactly.

C25, C30 and C35 Concrete — Driveways, Reinforced Work and Structural Use

C25 and C30 are the grades many UK customers compare when ordering ready-mix for driveways, garage floors and reinforced domestic work. C25 is commonly selected for domestic driveways and external paving where the loading is reasonable and the slab is correctly designed. C30 is a common upgrade where there are heavier vehicles, commercial traffic, agricultural use, higher abrasion or a more demanding durability requirement. The difference is not just the number on the delivery ticket. A higher grade may have a richer cementitious content, lower water-cement ratio or different admixture strategy, depending on the supplier and specification.

C35 moves further into structural territory. It is often associated with reinforced slabs, retaining walls, columns, beams, suspended slabs, pile caps and structural concrete where a designer has determined the demand. If you are ordering C35, you should be thinking about reinforcement position, cover, spacers, crack control, compaction, joints and curing. A strong mix placed around badly positioned reinforcement is not a good structural solution. Strength class, detailing and workmanship all need to line up.

C20 vs C25 vs C30: which one should you choose?

For a simple domestic slab with light use, C20 may be enough. For a driveway or garage floor, C25 is often a more practical baseline. For heavier vehicles, steeper access, shared drives, commercial vans or a slab that also needs better abrasion resistance, C30 may be more suitable. The final choice should consider depth, reinforcement, sub-base, joints and exposure. A 150mm C25 slab on a well-compacted base may outperform a thinner C30 slab on weak ground. Concrete grade is important, but it is not magic.

When comparing quotes, ask suppliers to confirm exactly what is included. One supplier may quote a practical “C30 driveway mix” while another quotes a formal C30/37 strength class with a specific slump, aggregate size and fibre option. One quote may include delivery within a certain radius, while another may include waiting time or a part-load charge. If the grade is different, the consistence is different or the access assumptions are different, the prices are not like-for-like. Use theDelivery Cost GuideandTruck Load Guideto compare more than the headline price per cubic metre.

C40, C45 and C50 Concrete — High Strength and Specialist Grades

C40, C45 and C50 concrete grades are normally used where high compressive strength, durability, abrasion resistance or engineering performance is required. These grades may appear in structural frame design, industrial floors, heavy-duty pavements, precast concrete, pile caps, bridge-related works, high-rise construction and other engineered applications. They are not typical casual DIY choices. If a project genuinely requires C40 or above, the concrete should be specified by someone competent to assess strength, durability and execution requirements.

High-strength concrete can bring benefits, but it can also introduce practical considerations. It may be less forgiving if water is added on site. It may need a controlled consistence for placing. It may generate higher heat in thick pours. It may need particular curing practice to avoid surface problems. It may have specific cement combinations, admixtures or aggregate requirements. In other words, high grade concrete is a system, not just a number.

For 2026 UK projects, high strength specification is also connected with sustainability and carbon decisions. Modern concrete specification is increasingly focused on performance, durability and appropriate cement combinations rather than simply increasing cement content. BS 8500:2023 introduced updated thinking around combinations such as CEM I with GGBS and limestone fines, and CEM I with fly ash and limestone fines, allowing specifiers to consider durability and lower-carbon approaches within the standard framework. For a domestic page, the practical takeaway is simple: use the right grade for the job, not the highest grade you can buy.

BS EN 206 and BS 8500: How UK Concrete Grades Are Specified

BS EN 206 covers the specification, performance, production and conformity of concrete. It helps define how concrete is specified, produced, controlled and assessed. In the UK, BS 8500 works alongside BS EN 206 and provides national provisions and guidance that reflect UK materials, exposure conditions and established practice. This is why many UK guides mention both standards together. BS EN 206 gives the broad concrete standard framework, while BS 8500 helps specifiers apply it correctly in UK conditions.

The most important thing for a buyer is to understand that the formal class is not the same as an informal trade name. Under BS EN 206 style notation, C25/30 tells you two strengths: cylinder and cube. The first number is cylinder strength and the second is cube strength. UK cube testing has long been common, so many people naturally talk about the cube value or supplier shorthand. Engineers and standards documents may be more precise, especially where Eurocode design is involved.

BS 8500 also deals with more than strength. It includes guidance related to exposure, durability, composition, limiting values, designated concretes, standardised prescribed concretes and the information that should be exchanged between specifier, producer and user. For example, concrete exposed to freeze-thaw cycles, chlorides from de-icing salts, aggressive ground or marine conditions may need a different specification from indoor concrete at the same nominal strength. A driveway in a wet, frosty, salted area can have a durability demand that a simple strength chart does not show.

When ordering ready-mix, ask for the mix in the terms required by your drawings or approval documents. If the drawing says C30/37, do not casually order “C30-ish”. If Building Control, a structural engineer or a warranty provider gives a designated concrete reference, use that reference. If you are unsure, send the supplier the exact wording from the specification. Good suppliers can help translate the requirement into the correct product, but they cannot guess the design intent if you only provide a vague job description.

Specifier:responsible for setting the required concrete performance and specification.
Producer:responsible for producing concrete that conforms to the specification and production control requirements.
User/contractor:responsible for receiving, placing, compacting, finishing and curing the concrete correctly.

Choosing the Right Grade by Project Type

Concrete Grade for Driveways

For a normal domestic driveway, C25 is commonly used, while C30 is often chosen for heavier traffic, vans, turning areas, shared drives or tougher exposure. Driveway performance also depends on sub-base depth, compaction, slab thickness, drainage, joints, reinforcement or fibres, finish and curing. In cold locations, freeze-thaw durability and de-icing salts should be discussed with the supplier.

Concrete Grade for Slabs

Domestic internal slabs may often fall in the C20 to C25 range, but structural slabs, suspended slabs and commercial slabs may require C30, C35 or higher. The right grade depends on loading, reinforcement, span, ground conditions and design. Use theConcrete Slab Guidefor volume, but use the project specification for strength.

Concrete Grade for Footings

Footings are controlled by ground conditions and structural load. C20 may be used for some simple domestic strip footings, while C25 or C30 may be specified for more demanding work. Extensions, retaining walls, poor ground and warranty projects should follow drawings and Building Control guidance rather than generic internet advice.

Concrete Grade for Reinforced Concrete

Reinforced concrete should follow the structural design. C25, C30, C35 and C40 can all appear depending on element type and exposure. Correct reinforcement cover, spacers, compaction and curing are just as important as strength. Adding more cement or ordering a higher grade does not fix poor reinforcement detailing.

A useful way to choose a grade is to start with the job category, then check the risk factors. Ask whether the concrete is internal or external, whether vehicles will use it, whether it is reinforced, whether it is in contact with soil or groundwater, whether it may see frost and salts, and whether it is part of a structural design. If several risk factors apply, the grade and durability specification may need to be upgraded. If the job is purely non-structural and protected, a lower grade may be economical.

How to Order the Correct Concrete Grade in 2026

Before calling a ready-mix supplier, collect the information that affects the order. You need volume in cubic metres, required grade or class, job type, access details, distance from truck to pour, whether a pump is needed, preferred delivery time, discharge method, consistence/workability, maximum aggregate size and any special requirements. If a drawing or specification exists, keep it in front of you during the call and repeat the exact wording. Do not rely on memory when the mix is structural.

For small domestic work, it is common to describe the job and ask the supplier for a suitable mix. That can be acceptable for patios, garden bases and simple paths, but it becomes risky for driveways, extensions, retaining walls and reinforced concrete. The supplier can advise on products they sell, but they are not usually responsible for designing your foundation, checking the soil, approving your reinforcement or confirming Building Regulations compliance. Where approval is needed, the concrete order should match the approved specification.

In 2026, ready-mix buyers should also consider market conditions. UK official construction material statistics and industry updates have shown weak ready-mixed concrete demand and continuing cost pressure. Lower demand does not automatically mean cheaper delivered concrete because plants, trucks, fuel, cement, labour, energy and compliance costs still affect the price. This makes correct ordering even more important. A second lorry, a failed pour or a rejected load can cost far more than a sensible grade decision made before delivery.

Work out the concrete volume using theReady-Mix Concrete Volume Guide.
Confirm the concrete grade or formal class from drawings, engineer notes, supplier guidance or Building Control requirements.
Check exposure, frost, salts, ground conditions, reinforcement and cover requirements.
Ask the supplier to confirm the correct mix designation, consistence, aggregate size and delivery method.
Prepare formwork, access, labour, resources, pump arrangements and curing method before the lorry arrives.

For related concrete mix design and proportion working, see MixDesignCalc.xyz.