土壤用量计算器
计算高架种植床、花盆和种植区域所需的土壤用量。输入床体形状和尺寸，即时获得立方英尺、立方码、所需袋数（1 立方英尺和 2 立方英尺）和预估重量。支持矩形、圆形和三角形种植床，含常用深度预设。
Soil Volume Calculator
Calculate how much soil you need for raised beds, pots, and garden beds
Dimensions
Frequently Asked Questions
土壤体积计算器是如何工作的？
土壤体积计算器根据种植区域的长、宽和深度计算所需土壤体积。对于矩形花坛：体积 = 长 × 宽 × 深；对于圆形花坛：体积 = π × 半径² × 深。结果可换算为立方英尺、立方米、升或袋数（按所选袋装规格）。
不同植物需要多深的土壤？
一年生花卉和蔬菜：15-30 cm（6-12 英寸）；多年生植物和草本：30-45 cm（12-18 英寸）；灌木：45-60 cm（18-24 英寸）；小乔木：60-90 cm（24-36 英寸）。深根植物需要更深的种植土层。
一袋土/堆肥能覆盖多大面积？
常见规格换算：1 立方英尺袋土（约 28 升）：以 5cm 厚铺设可覆盖约 0.56 m²（6 平方英尺）；以 10cm 厚可覆盖 0.28 m²。本计算器支持按不同袋装规格（1 cu ft、2 cu ft、40L 等）计算所需袋数。
散装土壤和袋装土壤哪个更经济？
一般而言，需要量超过 1-2 立方米时，散装土壤（按立方米计价）比袋装土更经济。但袋装土更易于运输、无需大型车辆，且成分更均匀稳定。本计算器同时显示体积和建议用量，方便您选择采购方式。
Soil Volume Calculator: Complete Guide for Raised Beds, Pots & Garden Beds
The Soil Volume Calculator helps you determine exactly how much soil to buy for raised garden beds, potted plants, in-ground garden beds, and other planting areas. It computes volume in cubic feet and cubic yards, estimates how many 1 cu ft or 2 cu ft bags you need, and provides a rough weight estimate to plan delivery logistics.
Soil Volume Formulas
The calculator uses standard geometry to compute volume. Depth is always entered in inches and converted to feet internally.
Rectangular Bed:
Circular Bed / Pot:
Triangular Bed:
Key Conversions:
- 1 cubic yard (yd³) = 27 cubic feet (ft³)
- 1 inch depth = 1/12 foot depth
- Bags needed = ⌈Volume ÷ Bag size⌉ (always round up)
Common Raised Bed Sizes
Use this reference table to quickly find the volume of popular raised bed sizes at common soil depths.
| Bed Size | 6" Deep | 8" Deep | 12" Deep | 1 cu ft Bags (12") |
|---|---|---|---|---|
| 2×4 ft | 4 ft³ | 5.3 ft³ | 8 ft³ | 8 bags |
| 4×4 ft | 8 ft³ | 10.7 ft³ | 16 ft³ | 16 bags |
| 4×8 ft | 16 ft³ | 21.3 ft³ | 32 ft³ | 32 bags |
| 4×12 ft | 24 ft³ | 32 ft³ | 48 ft³ | 48 bags |
| 4×16 ft | 32 ft³ | 42.7 ft³ | 64 ft³ | 64 bags |
| 3×6 ft | 9 ft³ | 12 ft³ | 18 ft³ | 18 bags |
Soil Types & Weight Reference
Soil weight varies significantly by type and moisture content. The calculator uses 75 lb/ft³ as a typical dry garden soil density. Here is a reference for common soil types:
| Soil Type | Approx. lb/ft³ | lb/yd³ | Notes |
|---|---|---|---|
| Dry garden / potting soil | 60–75 | 1,620–2,025 | Light; used in this calculator |
| Moist garden soil | 80–100 | 2,160–2,700 | After watering |
| Topsoil (loose) | 75–85 | 2,025–2,295 | Varies by clay/sand content |
| Compost | 40–55 | 1,080–1,485 | Very light; high organic matter |
| Clay soil (wet) | 100–130 | 2,700–3,510 | Heavy; poor drainage |
| Mel's Mix (square foot gardening) | 45–55 | 1,215–1,485 | 1/3 peat, 1/3 compost, 1/3 vermiculite |
Weight tip:A typical pickup truck can safely carry about 1,000–1,500 lb of soil. If you need more than 1 cubic yard (~2,000 lb), arrange for a bulk delivery rather than carrying bags in a passenger vehicle.
Amending Soil Tips
For raised beds and container gardening, pure topsoil is rarely the best choice. Here are proven amendments to improve soil performance:
For Raised Beds
- 60% quality topsoil or garden soil
- 30% compost (aged)
- 10% perlite or coarse sand for drainage
For Containers & Pots
- Use a premium potting mix (not garden soil)
- Add perlite (20%) to prevent compaction
- Refresh or replace annually
Improving Clay Soil
- Add 3–4 inches of compost and till in
- Gypite or gypsum to loosen clay structure
- Avoid working when wet
Improving Sandy Soil
- Add 2–4 inches of organic matter annually
- Coconut coir helps retain moisture
- Biochar improves water retention long-term
How to Calculate Soil Volume
- Choose your bed shape — rectangular for standard raised beds, circular for pots and round beds, triangular for corner beds.
- Measure the dimensions — length and width in feet for rectangles; diameter in feet for circles; base and height for triangles.
- Set the soil depth — use the preset buttons (6", 8", 12", 18") or enter a custom depth. Most vegetables need 12" minimum.
- Click Calculate — see results in cubic feet, cubic yards, bags needed, and estimated weight.
- Add 10% extra — soil settles after watering, so always buy a little more than calculated.
Related Tools
- Mulch Calculator — calculate how much mulch you need to cover garden beds and landscaping areas.
- Pea Gravel Calculator — estimate volume and weight of gravel for pathways, driveways, and decorative use.
- Plant Spacing Calculator — plan how many plants fit in a raised bed at your chosen spacing.