Correct unit conversion
Switch between metric and imperial while keeping equivalent project dimensions.
Project quantities without the guesswork.
Estimate volume, weight, waste and material cost for common outdoor and construction projects in imperial or metric units.
Multiple materialsMetric + imperialWaste allowancePrintable plan
Project dimensions
Use the finished area dimensions. Add a realistic waste allowance.
Concrete slab
Order volume
0 yd³
Estimated weight
0 tons
Base volume
0 yd³
Estimated cost
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Your material plan
Enter dimensions to generate an estimate.
Planning estimate only. Confirm compaction, site conditions, density and supplier minimums.
One measurement, clearer purchasing.
Change material without re-entering the project dimensions.
Waste included
See base volume and order volume separately, so the buffer is never hidden.
Cost-aware
Add a supplier price to turn a quantity estimate into an early budget.
Turn site dimensions into a defensible order estimate.
The core calculation for a rectangular project is length × width × depth. All three measurements must use compatible units before multiplication. Ready Materials converts the result into common supplier units and shows the base amount separately from the waste-adjusted order amount.
Measure depth carefully
Depth is often the smallest number and the easiest source of a large mistake. Four inches is one-third of a foot, not 0.4 feet. Measure several points when the excavation or base is uneven.
Example: 12 ft × 10 ft × 4 in slabConvert 4 inches to 0.333 feet. Base volume is about 40 cubic feet, or 1.48 cubic yards. With 10% waste, the planning quantity is about 1.63 cubic yards before supplier minimums or project-specific adjustments.
Waste is not one universal percentage
Cut pieces, irregular boundaries, settling, compaction, spillage and uncertain dimensions affect materials differently. Use the calculator’s percentage as an explicit planning assumption, then confirm it with drawings, site conditions and the supplier.
Read the full material volume and waste guide →
Last updated 6 September 2026. Density and cost outputs are estimates; supplier specifications and professional plans take priority.
Common questions
Material calculator FAQ
Why must units be consistent?
Multiplying feet by feet by inches does not produce a valid cubic unit. Convert each dimension into the same base system before calculating volume.
How much waste should I add?
There is no universal answer. Simple rectangular placement may require less than a complex cut pattern or uncertain excavation. Use project documents and supplier advice.
Why can delivered weight differ?
Bulk density changes with grading, moisture, voids and compaction. The calculated weight is useful for early planning, not loading certification.
Does estimated cost include delivery or tax?
No. It multiplies order quantity by the unit price entered. Delivery, tax, short-load charges, pallets, labor and equipment are separate unless included in your unit price.
Can this replace an engineer or supplier quote?
No. Confirm structural work, load limits, specifications, local requirements and final ordering with qualified professionals and suppliers.