Garden Bed Area Calculator

Plan raised beds with confidence using flexible shape options. Convert units, include waste, and estimate costs. Clear outputs help crews measure faster on site.

Calculator

Pick the shape that matches your bed footprint.
All dimensions use the same unit.
Multiply results for repeated beds.
Adds cushion for cuts, settling, and rounding.
Used to estimate soil volume.
For sod, fabric, pavers, or finish pricing.
For soil, compost, gravel, or mulch delivery.
Uses perimeter where available.
Rectangle / Square
Area = length × width; Perimeter = 2 × (length + width).
Circle
Area = πr²; Perimeter = 2πr.
Oval / Ellipse
Area = πab (a,b are semi-axes). Perimeter uses a proven approximation.
Triangle
Area = ½ × base × height. Add two side lengths to get perimeter.
Trapezoid
Area = ½ × (base1 + base2) × height. Add side lengths for perimeter if needed.
L-Shape (corner cutout)
Area = (outer L×W) − (cutout L×W). Perimeter assumes a corner cutout.
Custom Polygon (points)
Uses the shoelace formula for area and sums segment lengths for perimeter. Enter points in order around the bed. Do not repeat the first point.
Results appear above after submission.

Example data table

Bed type Inputs Area result Depth Volume estimate
Rectangle 8 ft × 4 ft 32 ft² 0.5 ft 16 ft³ (before waste)
Circle Diameter 6 ft 28.27 ft² 0.33 ft 9.33 ft³ (before waste)
Polygon 0,0; 8,0; 8,3; 2,3; 2,6; 0,6 (ft) 36 ft² 0.5 ft 18 ft³ (before waste)

Formula used

Waste factor is applied as: Adjusted = Base × (1 + waste/100). Volume uses: Volume = Adjusted area × depth.

How to use this calculator

  1. Select a bed shape that matches your layout.
  2. Choose the unit you measured with on site.
  3. Enter dimensions, then add number of beds.
  4. Add a waste percentage for cuts and settling.
  5. Enter depth to estimate soil or mulch volume.
  6. Optionally enter prices for area, volume, and edging.
  7. Press Calculate, then download CSV or PDF reports.

Planning guide

1) Why area matters on site

Garden beds look simple, but takeoffs rarely are. Accurate plan area controls how much fabric, soil, compost, mulch, and edging you order. A 10% error on a 120 ft² layout adds 12 ft² of waste and extra hauling. Measure carefully, then apply a realistic overage for cuts and settling.

2) Typical bed sizes and benchmarks

Common raised-bed footprints include 4×8 ft (32 ft²), 4×12 ft (48 ft²), and 3×6 ft (18 ft²). For circles, a 6 ft diameter is about 28.27 ft² and an 8 ft diameter is about 50.27 ft². Benchmarks help catch bad measurements before ordering.

3) Depth drives volume

Depth converts area into cubic measure. Example: 32 ft² at 0.5 ft depth needs 16 ft³ before overage. Many suppliers quote by cubic yard: 1 yd³ equals 27 ft³. That bed is about 0.59 yd³, and with 10% overage it becomes roughly 0.65 yd³.

4) Waste factor guidance

Waste depends on shape complexity and material behavior. Straight rectangles may need 3–7% extra for trimming and compaction. Curves, polygons, and multiple beds often justify 7–12%. Loose fills can settle 5–15% after watering. Using the waste input creates a clear, defendable buffer.

5) Perimeter and edging

Perimeter matters for borders, pavers, timbers, or steel edging. A single 4×8 ft bed has a 24 ft perimeter. Ten identical beds need 240 ft, plus splices and corners. For triangles and trapezoids, add side lengths to compute perimeter; base and height still give area.

6) Irregular beds with polygons

Many beds follow property lines or hardscape curves. The polygon option uses ordered corner points to compute area with the shoelace method and sums edge lengths for perimeter. Record points around the boundary from a consistent reference and keep the order clockwise or counterclockwise.

7) Cost estimating by unit

Vendors price by ft², yd², yd³, or m³ depending on region. The calculator converts results so you can match invoice units. If mulch is 45 per yd³ and you need 2.8 yd³, the material subtotal is 126. Add delivery, labor, and disposal as separate line items.

8) Reporting for crews

After calculation, export CSV for spreadsheets and PDF for job folders. Store the shape, units, bed count, overage, and depth so the takeoff is auditable. Add a date, crew name, and lot reference for traceability. Consistent reporting reduces change orders and keeps purchasing aligned with the approved plan.

FAQs

1) What waste percentage should I use?

Use 3–7% for straight rectangles and clean cuts. Use 7–12% for curved or irregular beds, multiple beds, or uncertain measurements. Increase if material settles significantly after watering.

2) Why does the tool show both area and volume?

Area supports fabric, liners, and surface finishes. Volume supports soil, compost, mulch, or gravel ordering. Add depth to convert area into a practical delivery quantity.

3) How do I enter a custom polygon correctly?

Enter points as x,y pairs separated by semicolons. Keep points in order around the boundary and do not repeat the first point at the end. Use one consistent unit for all points.

4) Why is perimeter sometimes not calculated?

Some shapes need side lengths to find perimeter. For triangles and trapezoids, base and height are enough for area, but edging needs the remaining sides. Enter optional side values to enable perimeter totals.

5) Can I estimate delivery quantities in cubic yards?

Yes. When depth is provided, the calculator outputs soil volume in m³, yd³, ft³, and liters. Use yd³ for most bulk landscape deliveries and compare with your supplier’s truck capacity.

6) How should I measure an L-shaped bed?

Measure the outer rectangle first, then measure the corner cutout rectangle. The area is outer minus cutout. Keep all measurements in the same unit and confirm the cutout does not exceed the outer size.

7) Are the CSV and PDF exports safe to share?

The exports contain only the inputs you typed and the computed results. They do not include personal identifiers unless you enter them as values. Use the files to attach takeoffs to work orders.

Accurate bed areas reduce waste, time, and surprises greatly.

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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.