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Every total is shown as a short sequence so you can see what was measured, deducted, adjusted and rounded.
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Concrete & Screed
Screed calculator
Estimate floor screed volume and optional bag quantities from floor area, average depth and waste.
Transparent formulaFormula v1.0 · floor length × width × average depth × waste allowance
Scope boundary: Materials estimate only — it does not specify floor build-up, substrate, damp protection, structural loading or compliance.
Measure clearly
Simple guidance
Measure the finished floor length and width, then use the intended average screed depth. Keep any separate insulation, membrane or floor build-up layers out of the screed depth.
Worked example
Follow the same logic
A 4 m × 3 m floor at an average 50 mm screed depth is 0.6 m³ before the selected waste allowance. The bag total is a purchase estimate, rounded up.
Planning tipWrite down the product factor or pack size you used, so a later change is easy to trace.
Before you buy
Three quick checks
- 01
Use the intended average screed depth across the finished floor.
- 02
Check the actual product's bag yield, mix guidance and minimum depth.
- 03
Keep substrate, damp protection and floor design decisions outside this estimate.
Quick answers
Useful to know
What is average screed depth?
Use the planned average thickness of the screed layer, not the whole floor build-up. Where a floor varies, use a sensible average and confirm with the installer or product guidance.
Can I use the bag total to place an order?
Use it as a planning quantity, then check the chosen product's stated yield, pack size and installation guidance before buying.
Review record
Transparent, source-ready method
Last reviewed: 15 October 2026. Formula version: v1.0. Source/review data to be added — Calculator.Shop does not present placeholder figures as an authoritative trade specification.