Joint Compound Calculator
Find how much drywall mud you need for your wall
Frequently Asked Questions
Base rate (kg per m² per mm of thickness) × wall area × coat thickness, adjusted for surface type and wall condition, plus a waste allowance.
A skim coat is typically 1-3mm; a leveling coat over rough or damaged drywall can be 3-6mm or more, applied in multiple thin passes rather than one thick one.
Porous surfaces (bare drywall, old plaster) absorb more compound than a previously painted or primed surface, so they need a higher coefficient applied to the base rate.
10-15% is a reasonable waste allowance to cover mixing losses, drying-out in the bucket, and touch-ups after sanding.