Plant Spacing CalculatorFree online other calculator — instant results, no sign-up
Estimate plant count on a square grid from bed area.
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About the Plant Spacing Calculator
The Plant Spacing Calculator estimates how many plants fit in a bed when arranged on a square grid. It uses bed area in square metres and center-to-center spacing in centimetres, with equal spacing between plants and between rows. For a 12 m² bed with 30 cm spacing, the estimated count is 133 plants.
- Bed area (m²)
- The usable planting area of the bed in square metres, with a default of 12 m².
- Center spacing (cm)
- The distance in centimetres from one plant's center to the next in both grid directions, with a default of 30 cm.
Formula and method
N = floor(A / (s / 100)²); with A = 12 and s = 30, N = floor(12 / 0.30²) = floor(133.333…) = 133 plants.
- NEstimated whole-number plant count.
- AUsable bed area in square metres.
- sCenter-to-center plant spacing in centimetres, used equally along rows and between rows.
- floorRounds down to the nearest whole number.
Convert spacing from centimetres to metres, then square it to find the area allocated to each plant on a square grid. Divide the bed area by that allocation and round down to a whole plant. With the defaults, 30 cm becomes 0.30 m, each plant is allocated 0.09 m², and 12 ÷ 0.09 gives 133.333…, reported as 133 plants.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Bed area12 m²
- Center spacing30 cm
Results
- Result133 plants
How to use the Plant Spacing Calculator
- 1Determine the usable planting area, excluding paths and sections that will remain unplanted.
- 2Enter that area in Bed area (m²); the default is 12.
- 3Enter the recommended center-to-center spacing in Center spacing (cm); the default is 30.
- 4Read the estimated plant count: the default inputs produce 133 plants.
- 5Check the proposed rows against the bed's actual dimensions and required edge clearances before planting.
Reading your result
The result row reports the estimated whole-number plant count for the entered area and square-grid spacing. A result of 133 plants means the 12 m² bed provides approximately 133 planting allocations at 30 cm spacing; it does not guarantee that exactly 133 planting positions fit the bed's shape.
Limitations
This is an area-based estimate, not a row-by-row layout calculation. It assumes uniform spacing on a square grid and does not account for bed dimensions, irregular boundaries, edge setbacks, paths, obstacles, or mixed plant sizes. Actual capacity may differ depending on how rows and margins are arranged. It does not model staggered or triangular planting, choose suitable spacing for a species, or allow for plant losses. Spacing must be greater than zero, and bed area must not be negative.
Common questions
Does 30 cm spacing mean a 30 cm gap between leaves?+
No. It means 30 cm from the center of one plant to the center of the next, both along a row and between rows. Foliage may overlap as plants mature.
Why does a 12 m² bed at 30 cm spacing return 133 plants?+
Each plant is allocated 0.30 × 0.30 = 0.09 m². Dividing 12 m² by 0.09 m² gives 133.333…, which is rounded down to 133 whole plants.
Can beds with the same area fit different numbers of plants?+
Yes. This calculator returns the same estimate for equal areas at the same spacing, but narrow beds, irregular edges, and required margins can change the number of complete rows and planting positions that actually fit.
Can I use this result for staggered planting or wider row spacing?+
Not directly. The formula assumes equal spacing in two perpendicular directions. Staggered layouts or rows spaced differently from plants within each row need a different layout calculation.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
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Results are estimates for informational purposes and are not financial, medical or legal advice.