Waste Tonnage Calculator — How Much Does My Construction Waste Weigh?

This calculator converts waste volumes (in m³) to weight (in tonnes) using standard material densities, then estimates the landfill tax payable based on the waste type classification.

Material Densities (indicative waste-form)

Based on WRAP and Environment Agency waste volume-to-mass conversion factors. These are typical skip/loose-form figures and vary with compaction, moisture and material mix — treat them as estimates, not fixed values.

• Plasterboard: ~800 kg/m³ (standard rate tax)
• Timber: up to ~500 kg/m³ (standard rate tax) — a conservative solid-timber upper bound; loose offcuts in a skip are far lighter (~130–400 kg/m³)
• Brick rubble: ~1,800 kg/m³ (lower rate tax — inert)
• Concrete rubble: ~2,200 kg/m³ (lower rate tax — inert)
• Soil: ~1,500 kg/m³ (lower rate tax — inert)
• Mixed waste: ~1,000 kg/m³ (standard rate tax) — mixed/general C&D waste varies widely (~0.3–1.0 t/m³); this is a conservative upper estimate

Landfill Tax Rates (from 1 April 2026)

• Standard rate: £130.75 per tonne (non-inert: plasterboard, timber, mixed, plastics)
• Lower rate: £8.65 per tonne (inert: brick, concrete, soil, stone)

Skip Size: Volume vs Weight

The recommended skip is the smallest size whose volume covers your total waste. But every skip also has a weight limit — roughly 2 t (2-yard), 4 t (4-yard), 6 t (6-yard) and 8 t (8-yard) per typical UK operator guidance. Dense waste such as rubble, concrete and soil reaches the weight limit long before the skip looks full, so the tool flags a warning when your calculated tonnage exceeds the chosen skip’s weight allowance. Rubble and hardcore are normally restricted to 8-yard skips or smaller, because a fully loaded larger skip would be too heavy for the collection lorry. Always confirm limits with your waste carrier.

Plasterboard Separation

Plasterboard must be kept separate from other waste by law. It cannot be placed in a mixed skip. It must go to a dedicated plasterboard recycling facility or a specific landfill cell that contains no biodegradable waste.