Enter Project Details
Example Data Table
These examples use 1.45 tons per cubic yard, 15% compaction allowance, and 10% waste allowance.
| Project | Size | Depth | Estimated Volume | Estimated Tons |
|---|---|---|---|---|
| Driveway base | 50 ft × 12 ft | 6 in | 14.06 cu yd | 20.39 tons |
| Patio subbase | 20 ft × 18 ft | 4 in | 5.62 cu yd | 8.15 tons |
| Walkway base | 80 ft × 4 ft | 4 in | 5.00 cu yd | 7.25 tons |
| Shed pad | 24 ft × 16 ft | 8 in | 12.00 cu yd | 17.40 tons |
Formula Used
The calculator first converts all area measurements to square feet. It then converts the planned depth to feet.
Compacted cubic yards = area in square feet × depth in feet ÷ 27
Loose cubic yards = compacted cubic yards × (1 + compaction allowance ÷ 100)
Order cubic yards = loose cubic yards × (1 + waste allowance ÷ 100 + moisture allowance ÷ 100)
Tons = order cubic yards × density in tons per cubic yard
Total cost = rounded tons × price per ton + delivery + tax
The result is a planning estimate. Supplier tickets, moisture, stockpile condition, and compaction method can change the final delivered weight.
How to Use This Calculator
- Select the shape that best matches your construction area.
- Enter length, width, diameter, triangle values, or custom area.
- Choose the matching dimension unit.
- Enter the final compacted depth required for the base.
- Set density from your supplier when available.
- Add waste, compaction, moisture, cost, delivery, tax, and truck settings.
- Press calculate to view the result above the form.
- Use the CSV or PDF button to save the estimate.
2A Modified Stone Planning Guide
What 2A Modified Stone Does
2A modified stone is a dense graded aggregate. It usually contains crushed stone, fines, and dust. The fines help the base lock together. This makes it useful under driveways, sheds, patios, walkways, retaining wall pads, and construction entrances.
Why Accurate Measuring Matters
A good estimate starts with the finished area. Measure the length and width carefully. Then select the planned compacted depth. Many light base projects use four to six inches. Heavier drives may need more depth, stronger subgrade prep, and better drainage.
Compaction and Waste
This calculator separates compacted volume from loose order volume. That is important. Stone shrinks during rolling, plate compaction, and traffic. A compaction allowance helps replace that lost volume. A waste allowance covers edge trimming, grading loss, spillage, and small measuring errors.
Density and Tonnage
Density controls the weight result. 2A modified stone is often ordered by the ton. Your supplier may quote a local density. Use that number when available. The default value is only a planning estimate. Moisture, quarry source, gradation, and handling can change actual tonnage.
Cost and Delivery Planning
Cost planning also matters. Enter a price per ton, delivery charge, and tax rate. The calculator returns material cost, delivery cost, tax, and grand total. It also estimates truckloads and bag counts. These values help compare bulk delivery with smaller retail bags.
Site Preparation Tips
For best results, check the subgrade before ordering. Remove soft organic soil. Add geotextile fabric when separation is needed. Keep water moving away from the base. Spread the stone in lifts when the planned depth is large. Compact each lift until it feels firm and stable.
Final Ordering Advice
Always round the final order up. Small shortages slow crews and create weak thin spots. Extra material can fill low areas, shoulders, or future repairs. Confirm depth requirements with project plans, local codes, or an engineer when the base supports vehicles or structures.
Using the Report
The example table shows how depth changes totals quickly. A small increase can add many tons. This is why the calculator keeps each assumption visible. You can adjust density, waste, and compaction without rebuilding the whole estimate. Save the CSV for records. Use the PDF when sharing a quote with a client, foreman, supplier, or purchasing team. It supports faster decisions and cleaner site communication.
FAQs
What is 2A modified stone?
It is a dense graded crushed stone mix. It includes larger aggregate and fine particles. The fines help the material compact tightly. It is commonly used for driveways, road bases, pads, and construction entrances.
What density should I use?
Use your supplier’s density when possible. A planning value near 1.45 tons per cubic yard is often used, but local stone can vary. Moisture, gradation, and quarry source can change the real weight.
Why does the calculator include compaction?
Loose stone settles and tightens during rolling or plate compaction. The compaction allowance adds material so the finished base can still reach the planned depth after it is compacted.
How much waste should I add?
Many projects use 5% to 15% waste. Use more for irregular shapes, rough grading, long hauling paths, or inexperienced placement. Use less for clean rectangular areas and controlled machine placement.
Should I order by tons or cubic yards?
Many suppliers sell 2A modified stone by the ton. Some quote cubic yards. This calculator shows both. Confirm the ordering unit before placing the material request.
Can this estimate replace engineering plans?
No. It is a planning tool. Structural pads, commercial drives, drainage areas, and code-controlled work may need engineered specifications. Always follow project drawings and local requirements.
Why is my truckload count rounded up?
Partial loads still require delivery planning. The calculator rounds truckloads up because a small remaining amount may still need another trip or a smaller delivery option.
Can I use this for other aggregate?
Yes, if you change the density and allowances. Different stone types compact differently. Sand, clean gravel, and open graded stone may need different values and installation methods.