Flower Bed Soil Calculator

Plan perfect beds with precise soil volume and bags. Switch units, choose shapes, and factor compaction or waste. Estimate cost, bag counts, and blends for custom mixes. Export CSV results or print neat PDF summaries. Save presets, share states, and work confidently outdoors today.

Settings
L
Common sizes: 25 L, 40 L, 50 L
$
%
%

Mix ratio (parts)
Beds
# Shape Dimensions Depth Qty Area Volume
Results
Total area
0.00
Volume
0.000
Bags needed
0 bags
Estimated cost
$0.00
Liters
0 L
Cubic feet
0.000 ft³
Cubic yards
0.000 yd³

Mix breakdown
Topsoil
0 L
Compost
0 L
Sand
0 L

Example data

Click Load example beds to populate the table below.

#ShapeDimensionsDepthQty
1RectangleLength 3, Width 1.225 cm2
2CircleDiameter 1.520 cm1
3AnnulusOuter Ø 2.2, Inner Ø 1.018 cm1
4Area onlyArea 4.030 cm1

How to use this calculator

  1. Select your measurement system, bag size, and costs.
  2. Add a bed row, choose its shape, and fill dimensions.
  3. Enter depth at finished grade; include waste and settling.
  4. Add multiple rows for different beds and quantities.
  5. Review totals, bag count, and cost; adjust settings if needed.
  6. Export a CSV for records or download a formatted PDF summary.
  7. Save presets to local storage; share a link with teammates.

Formulas used

FAQs

Geometric volume is exact to your inputs. Real-world soil settles, edges curve, and ground varies. Use waste and settling percentages for realistic ordering.

Most ornamental beds use 15–30 cm (6–12 in). Deep-rooted shrubs or raised beds may need more. Follow plant recommendations and local practices.

Bag count divides total liters by chosen bag capacity. Larger bags reduce handling but may change price per liter. Update cost to compare.

Waste covers spillage and trimming. Settling accounts for post-install compaction and voids. Both multiply required volume; adjust per site conditions.

Yes. Choose “Area only,” provide area in current units, then enter depth. This suits curved borders measured from a plan or wheel.

Parts are proportional. For example, 3:1:0 splits total liters into 75% topsoil, 25% compost, 0% sand. Change parts to match your blend.

Yes. Use Rectangle for raised beds, Circle for tree rings, or Annulus for donut-shaped beds around trunks or planters.

Reference tables & guides

Recommended bed depths by plant type
Plant type Typical depth (cm) Typical depth (in) Notes
Annual flowers10–204–8Shallow roots; refresh with compost annually.
Perennials20–308–12Allow room for crowns and seasonal divisions.
Shrubs (small)30–4512–18Deep organic layer improves establishment.
Bulbs15–256–10Depth varies by species; check bulb size guides.
Groundcovers8–153–6Even, shallow layer; consider edging for consistency.
Bag coverage at common depths

Coverage assumes loose-fill soil. Compaction and waste reduce coverage in practice.

Bag size (L) 5 cm (m²) 10 cm (m²) 20 cm (m²)
25 L0.500.250.13
40 L0.800.400.20
50 L1.000.500.25
80 L1.600.800.40
Bag size (ft³) 2" (ft²) 4" (ft²) 8" (ft²)
1 ft³6.03.01.5
1.5 ft³9.04.52.25
2 ft³12.06.03.0
3 ft³18.09.04.5
Suggested soil mix ratios by application
Use case Topsoil : Compost : Sand (parts) Notes
General flower beds3 : 1 : 0Rich organic layer; good moisture retention.
Improved drainage3 : 1 : 1Add sand to reduce waterlogging in heavy soils.
Seed starting/annuals2 : 2 : 0Higher compost for nutrients; keep depth shallow.
Bulb beds3 : 0.5 : 0.5Moderate sand to prevent rot around bulbs.
Container/raised beds*2 : 1 : 1*Consider lightweight amendments (perlite/bark fines).
Typical bulk densities & mass reference

Values are approximate; moisture content and local sourcing cause significant variation.

Material Bulk density (kg/m³) kg per liter lb per cubic yard
Topsoil (loamy)12001.20~2020
Compost (screened)6000.60~1010
Horticultural sand16001.60~2690
Peat/peat-based mix2500.25~420
Wood mulch (fine)4000.40~670

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.