Concrete calculator
Base Material Calculator
Enter the specified compacted base depth, area, and supplier density. The order rounds up to half a US ton; the cost includes that rounded order and one delivery.
Planning estimate, not a contractor quote. Review the assumptions and replace presets with local prices when available.
Method
How this calculator works
Aggregate base under a slab or patio is a separate material from the finished surface. Start with the specified compacted depth, add an explicit allowance, and use the supplier’s density for the selected product.
Volume = length × width × depth. Adjusted cubic feet = volume × allowance. Tons = adjusted cubic feet × density in lb/ft³ ÷ 2,000. Delivered material estimate = rounded order tons × price per ton + delivery fee.
Worked example
A realistic starting point
A 20 ft by 10 ft area at 3 in deep is 1.85 yd³ before allowance. With 10% and a 105 lb/ft³ density, it needs about 2.89 tons. The suggested half-ton purchase quantity is 3 tons.
What changes the answer
Factors worth checking
Stone density
Ask the supplier for its conversion for the exact product. Washed stone, dense grade, and rounded gravel do not weigh the same.
Compacted depth
A driveway base is specified after compaction. Loose delivery volume may be larger than the final compacted layer.
Subgrade loss
Soft or uneven ground can consume extra material. Geotextile and proper preparation may reduce contamination and settlement.
Delivery minimums
The calculated material cost may be lower than the supplier’s delivered minimum. Confirm truck capacity, delivery charge, and dump access.
Common questions
Aggregate base FAQ
How many tons are in a cubic yard of gravel?
It varies. Use the supplier’s product-specific density rather than a single universal conversion.
How deep should driveway gravel be?
Depth depends on soil, drainage, traffic, material gradation, and local practice. Use a designed section or contractor recommendation.
Should I include compaction?
Yes, but make it explicit. Enter the final compacted depth and adjust the allowance using supplier or project guidance.
Why is cost based on the rounded order?
It matches the recommended purchase quantity. Confirm supplier minimums, tax, and delivery tiers before ordering.
Evidence
Sources & review
- FHWA Gravel Roads ManualTechnical context for aggregate, drainage, and compaction.
- NIST SI Units — MassUnit reference for mass conversions.
Published by Calcstead. Report a correction.
Method and source links reviewed September 5, 2026. Price presets are editable planning inputs and should be replaced with current local information.