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Decking Calculator
Boards, joists and cost for a timber or composite deck.
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⚡ Instant Results
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Boards to buy (10% waste)
Compare Your Options And Get Clear Answers
Boards, joists and cost for a timber or composite deck.
Decking Estimator
Enter your numbers below for an instant estimate.
0
💡 Tip: Boards = rows x boards per row x 1.1.
How It Works
Key concepts behind this calculator
1
Enter Values
Fill in each field with your own numbers.
2
Calculate
Results update as you change the inputs.
3
Review
Read the breakdown and the explanation.
4
Adjust
Change values to compare scenarios.
Quick Reference Guide
Decking Quick Guide
Typical values for reference.
| Length m | Width m | Board mm | Boards |
|---|---|---|---|
| 4 | 3 | 140 | 47 boards |
| 3 | 3 | 120 | 27 boards |
| 6 | 4 | 140 | 62 boards |
| 5 | 2.5 | 150 | 38 boards |
| Rule of Thumb | Check inputs | Use as a guide | Round sensibly |
Common Questions
Decking Calculator FAQ
Answers to common questions about this calculator.
Divide deck width by board width plus gap, then allow waste.
Typically 400 mm for timber, 300 mm for composite.
Yes, for drainage and expansion.
No.