The calculation, explained.
Extra quantity = starting quantity × allowance/100. Total quantity = starting quantity + extra. Packaging and individual-product purchase increments are not inferred.
Review the example assumptions and results
- Starting quantity
- 100 units
- Extra material
- 15 %
- Extra
- 15 units
- Total
- 115 units
How this tool works
Adjust the labeled inputs to see a new calculation. Units and assumptions are shown beside each field. Printed and copied results use the same calculation.
This is a planning estimate, not a structural design, permit document or binding quote. Check product specifications and actual site measurements.
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