Decking calculator
Estimate outputs: Area, Total board length, Whole pieces. Adjust Length, Width, Board face width to match your project.
Estimate outputs: Area, Total board length, Whole pieces. Adjust Length, Width, Board face width to match your project.
Inputs and units
Use the units shown beside each field. Replace the sample values with your measurements and the figures on the selected product packaging.
| Parameter | Example input |
|---|---|
| Length | 6 m |
| Width | 4 m |
| Board face width | 14 cm |
| Gap between boards | 0.5 cm |
| Board length | 4 m |
| Waste allowance | 10 % |
Formula and assumptions
Total board lengthLength × Width / ((Board face width + Gap between boards) / 100) × (1 + Waste allowance / 100)
Whole piecesceil(Total board length / Board length)
ceil = round up; floor = round down; max = the greater value. Trigonometric angles are converted from degrees to radians.
Allowance is applied before rounding to whole packages. Whole units are rounded up; displayed decimals are rounded only for readability.
Bulk density and compaction vary with moisture and the delivered material. The allowance does not model compaction; obtain the ordering conversion from your supplier.
Worked example
Sample values are examples, not product specifications. Run the calculation again with your own measurements.
| Result | Calculation |
|---|---|
| Area | 24 m² |
| Total board length | 182.069 m |
| Whole pieces | 46 |
Related calculators
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These are quantity estimates. Confirm product coverage, site conditions and required dimensions before ordering.