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Vriksai Timber Intelligence

Waste Margin CalculatorWaste & Material Margin Calculator

Work out how much raw timber to order to deliver a finished quantity. Account for compounding defect, processing and cutting losses plus a safety margin, and see your true total waste and cost.

Gross Input NeededCompounding LossesSafety MarginTrue Waste %PDF Report
WM

Waste Margin Calculator

Waste & Material Margin Calculator

Final Requirement
units

Net finished output you must deliver.

INR
Loss Factors
%

Knots, splits, rejects.

%

Drying shrink, planing, machining.

%

Saw kerf, offcuts, trim.

%

Extra buffer stock.

OK
Waste Margin Results
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to order
Gross Input Needed
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waste
Total Waste
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%
Waste Percentage
-
INR
Total Cost
FactorValueDetail
Waste Margin Calculation
About Waste Margin Calculator
To deliver a finished quantity of timber you must start with more - enough to absorb defect rejection, processing shrinkage, cutting waste and a safety buffer. The crucial insight is that these losses compound multiplicatively, not additively. This tool works backward from your final requirement to the gross input you must order, and shows the true total waste and cost.
Where Is This Used?
Material OrderingJob CostingProduction PlanningPurchase SizingQuotation AccuracyInventory Control
Formulas Used
Retention = (1-defect%) x (1-process%) x (1-cutting%)Gross before safety = Final qty / RetentionTo order = Gross x (1 + safety%)Total waste = To order - Final qtyNote: losses multiply - 10%+10%+10% leaves 72.9%, not 70%
Frequently Asked Questions
Why multiply the losses instead of adding them?
Each loss acts on what survives the previous stage, not on the original amount. If you lose 10% to defects, 90% remains; losing 10% of that in processing leaves 81%, and another 10% cutting loss leaves 72.9%. Adding (giving 70%) underestimates the material you actually need - a common and costly ordering mistake.
How do I work backward from finished quantity?
You divide, not multiply. If you need 10 m3 finished and your overall retention is 72.9%, you must order 10 / 0.729 = 13.72 m3 of input. This tool does the reverse calculation automatically so you order enough to net exactly what the job requires, plus your chosen safety margin.
What safety margin should I add?
5% is a reasonable default for well-understood jobs. Increase it for new species, unfamiliar suppliers, tight-tolerance work, or when running short would halt production or break a delivery promise. Balance the cost of extra stock against the cost and delay of running out mid-job.
ResourcesView the formulasFormula Library
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