Concrete Weight Calculator UK

How the Concrete Weight Calculator Works

Enter dimensions of your slab or element or a known volume and choose concrete type. The calculator multiplies volume by density to return weight in kilograms and tonnes.

The formula is simply weight = volume x density. Standard concrete has a density of 2,400 kg/m³ and for reinforced concrete UK and European structural practice assumes 2,500 kg/m³ to cover embedded steel. Those two figures answer the vast majority of weight questions on site.

Concrete Densities by Type

Density varies with aggregate, which is why the type matters:

• Standard concrete: 2,400 kg/m³
• Reinforced concrete: 2,500 kg/m³, the Eurocode design assumption including rebar
• Lightweight concrete: roughly 1,450 to 1,850 kg/m³ depending on the aggregate
• Aircrete blocks: as low as 600 to 800 kg/m³, which is why they lift one handed

Freshly poured concrete weighs slightly more than fully cured concrete because some mixing water evaporates over months after the pour, though difference is small enough to ignore for most practical purposes.

Quick Reference: Slab Weights

So a typical 3m x 2m garden slab at 100mm weighs around 1.44 tonnes and a single garage base at 6m x 3m and 150mm comes to about 6.5 tonnes. Numbers like these explain why concrete deliveries are measured against vehicle limits, a fully loaded 6m³ ready mix truck carries over 14 tonnes of concrete alone.

Why Concrete Weight Matters in Practice

Three situations bring people to this calculation. Structural loading first, concrete's self weight is a major part of dead load on beams, floors and foundations, which is why engineers work from 2,500 kg/m³ reinforced figure. Transport second, a builder's trailer rated at 750kg fills with just a third of a cubic metre of broken concrete and overloading is both illegal and dangerous.

Demolition and disposal third and this is one that surprises people. Breaking out a modest 10 m² patio at 100mm produces around 2.4 tonnes of rubble. An 8 yard skip is typically limited to about 8 tonnes and smaller skips much less, so weight rather than volume usually decides how many skips a concrete break out needs. Grab lorries price by weight for the same reason.

Worked Example: Garage Base Disposal

Breaking out a 4m x 3m reinforced garage base at 150mm to plan disposal:

• Volume: 4m x 3m x 0.15m = 1.8 m³
• Weight at 2,500 kg/m³: 4.5 tonnes
• Broken concrete bulks up in volume by around 30 percent but the weight stays the same
• Disposal: one 8 yard skip on weight or a grab lorry load with room to spare