Use this page as an estimating workflow rather than a specification. Build the quantities in the order shown, use the linked calculators for the arithmetic, then verify every product-specific value against the material you intend to buy.
Start with the finished base footprint
Measure the required length and width of the base, then record each layer depth separately.
Calculate excavation independently
The amount removed depends on total dig depth, not just concrete thickness. Keep spoil planning separate from imported material quantities.
Estimate sub-base and concrete as separate layers
Use the same footprint only where the design actually calls for full-area layers. Edge beams or local thickening should be measured separately.
Round after comparing supplier units
Concrete may be ordered as bags or ready-mix; sub-base may be tonnes or bulk bags. Convert only after the geometric quantities are established.
Calculators for this job
Common mistakes
- Using the concrete depth as the total excavation depth
- Forgetting side clearance or formwork space
- Assuming bulk-bag mass is universal
- Combining sub-base and concrete allowances
Pre-order checklist
- Re-measure the main dimensions or compare them with a current drawing.
- Replace generic coverage, density, spacing or pack figures with the actual product data.
- Keep the base quantity, waste allowance and pack rounding as separate steps.
- Check whether any part of the job requires professional design, approval or a manufacturer-specific installation method.
- Save the raw measurements so the estimate can be reproduced if the supplier queries it.
The project planners deliberately stop at quantity planning. They do not certify structural adequacy, regulatory compliance or installation suitability.