Calculator Inputs
Enter the two right-angle legs, soil depth, waste, settlement, bag size, density, delivery capacity, and cost details.
Formula Used
Right triangle area: Area = 0.5 × base leg × perpendicular leg
Average depth: Average depth = (shallow depth + deep depth) ÷ 2
Raw soil volume: Volume = triangle area × average depth
Pre-settlement volume: Raw volume × (1 + waste% + crown%)
Order volume: Pre-settlement volume ÷ (1 − shrinkage%)
Bag count: Ceiling(order volume ÷ one bag volume)
Cost: Quantity × unit price, based on the selected pricing method.
How to Use This Calculator
- Measure the two straight sides that meet at the right angle.
- Enter the shallow and deep soil depths. Use equal depths for a flat bed.
- Select the correct units for length, depth, bags, and truck capacity.
- Add a waste percentage for spills, edge trimming, and field variation.
- Add shrinkage if the soil will settle after watering or light compaction.
- Enter bag size, density, delivery capacity, price, and pricing basis.
- Press the calculate button. The result appears above the form.
- Download the CSV or PDF report for records, bids, or purchase planning.
Example Data Table
| Project | Base leg | Height leg | Average depth | Waste | Shrinkage | Approximate order |
|---|---|---|---|---|---|---|
| Small herb triangle | 6 ft | 4 ft | 8 in | 8% | 10% | 0.36 yd³ |
| Raised corner bed | 12 ft | 8 ft | 9 in | 8% | 12% | 1.66 yd³ |
| Large landscape wedge | 18 ft | 14 ft | 10 in | 10% | 15% | 5.05 yd³ |
Right Triangle Bed Soil Planning Guide
Why Triangle Soil Estimates Matter
A right triangle bed looks simple, yet soil ordering can go wrong quickly. Two straight legs form the right angle. Those legs define the surface area. The fill depth turns that area into volume. This calculator combines those values with waste, shrinkage, bags, density, and hauling capacity.
Measure the Shape Correctly
For construction work, the triangle shape matters. Rectangular shortcuts overestimate material. Guessing from the longest side also gives poor results. A right triangle bed uses one half of a matching rectangle. That makes the base and height measurements very important. Measure both legs from the exact inside edges of the border.
Choose Practical Fill Depths
Depth is another key input. Raised beds often settle after watering. Native soil can also mix with imported material. Use the shallow and deep depth fields when the bed is not level. The calculator averages those depths. It then multiplies the average by the triangle area. This gives a practical field estimate.
Include Waste and Shrinkage
Waste and shrinkage protect the order. Waste covers spillage, trimming, uneven grading, and small measurement errors. Shrinkage covers compaction and settling after placement. A dense clay mix may shrink differently from compost rich soil. Builders should choose realistic percentages. Small beds may need a higher safety margin because bags are sold in fixed sizes.
Use Outputs for Ordering
The calculator also estimates mass, bag count, load count, and cost. Bulk density converts volume into approximate weight. Bag size turns ordered volume into a purchase quantity. Truck capacity helps schedule deliveries or site movement. Unit price creates a direct budget estimate. These outputs are useful for garden beds, landscape borders, triangular planters, and small retaining projects.
Final Site Checks
Always confirm field measurements before buying soil. Check the bed shape after edging is installed. Remove large debris before measuring depth. Use the same unit system across the form when possible. If the soil will be compacted in layers, apply shrinkage. If the bed needs a crowned finish, raise the waste factor. Keep a record of the final result. The CSV and PDF buttons help create that record for contractors, clients, or personal project files. After delivery, spread soil in thin lifts. Lightly water each lift. Recheck finished height before planting, paving, or installing irrigation lines on site today.
FAQs
1. What is a right triangle bed?
A right triangle bed has two straight sides meeting at 90 degrees. The third side is the diagonal edge. Soil volume is based on half of the matching rectangle area.
2. Which sides should I measure?
Measure the two sides that form the right angle. Do not use the diagonal side as the base or height unless you convert the geometry first.
3. Why does the calculator use average depth?
Many beds are not perfectly level. Average depth gives a practical estimate when one side is shallow and another side is deeper.
4. What waste percentage should I use?
Use 5% to 10% for careful work. Use 10% to 20% for irregular edges, loose placement, or uncertain measurements.
5. What does shrinkage mean?
Shrinkage means the soil settles after watering, walking, or light compaction. Adding shrinkage helps prevent a low finished bed.
6. Can I use this for raised beds?
Yes. Enter the inside bed measurements and the intended fill depth. Add a crown factor if you want soil above the frame line.
7. Why is bag count rounded up?
Bags are purchased as whole units. The calculator rounds up so the ordered bag volume can meet or exceed the required volume.
8. Is the weight estimate exact?
No. Weight depends on moisture, material mix, and compaction. Use the density field to match your supplier’s soil data when available.