Garden Bed Area Calculator
Calculate the area and perimeter of rectangular, circular, triangular, or L-shaped garden beds.
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How to use this calculator
Choose your garden bed shape and enter the relevant dimensions. Area determines material quantities; perimeter determines edging length.
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Select your garden bed shape.
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Enter the relevant dimensions in metres.
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Read off the area in m² and sq ft for calculating soil and mulch needs.
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Use the perimeter to purchase the correct amount of garden edging.
Frequently asked questions
How do I calculate the area of an irregular-shaped bed?
Break irregular shapes into simpler shapes (rectangles and triangles), calculate each separately, and add them together. For very complex curves, use the grid method: overlay a grid of 0.5 m squares and count how many fall inside the bed.
What is garden edging used for?
Garden edging creates a clean visual border between beds and lawn, prevents grass from spreading into beds, and helps contain mulch. Steel, aluminium, timber, brick, and plastic are common edging materials.
How many square metres is a standard raised bed?
A typical raised bed is 1.2 × 2.4 m (approximately 2.9 m²). This size allows you to reach the centre from either side without stepping into the bed, which prevents soil compaction.
Garden Bed Area Calculator — Rectangle, Circle, Triangle & L-Shape
Why Calculate Garden Bed Area?
Knowing your garden bed area accurately means you buy exactly the right amount of soil, mulch, compost, and fertiliser — no more guessing and making multiple trips to the garden centre. It also lets you calculate how many plants you need at a given spacing.
Circular and Curved Garden Beds
Circular beds have a warm, informal look. The area of a circle is π × radius². A 2-metre-diameter circular bed has an area of about 3.14 m² — only 44% of the area of a 2 × 2 m square bed, so they need less material than you might expect.
Garden Edging Length
The perimeter of your bed tells you how many linear metres of edging to purchase. Always add 10% for corners and joins. Steel or aluminium roll edging typically comes in 10 m lengths; brick and timber edging is priced by the linear metre.
Learn more from an authoritative source:
WikipediaMulch Calculator
Calculate how many cubic yards or cubic metres of mulch you need for a garden bed, plus bags required.
Raised Bed Soil Calculator
Calculate how much soil and compost you need to fill a raised garden bed, with mix breakdowns.
Lawn Seed Calculator
Calculate exactly how much grass seed you need based on lawn area, grass type, and seeding purpose.
Plant Spacing Calculator
Calculate how many plants fit in a garden bed using square grid or triangular offset planting patterns.
Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →