Sawdust Waste EstimatorKerf Loss and Lumber Recovery Calculator
Estimate sawdust, slabs, edging and total waste from log sawing. Calculate Lumber Recovery Factor, overrun vs log rules, and INR value of waste for biomass or panel board feedstock.
Why this calculation matters
Residue volume decides disposal or resale, and it is a direct read on how much of each log is being lost to the saw.
Sawdust Waste Estimator
Kerf Loss and Lumber Recovery Calculator
Bandsaw: 2-3mm. Circular: 3-4mm. Gang: 3.5mm. Chainsaw: 6-9mm.
| Component | Volume m3 | Mass kg | % of Log |
|---|
About Sawdust Waste Estimator
Every saw cut removes material as sawdust - 3-4mm of wood per pass. For a 25mm board with 3.2mm kerf, over 11% of each board's thickness becomes sawdust. This tool calculates kerf waste, slab and edging waste, actual lumber recovery, and the biomass value of the waste stream for panel board or fuel use. Mills use it to estimate sawdust volume and overall sawmill waste percentage before quoting a custom cutting job.
Where Used?
Formulas
Boards per pass = floor(D_cm x 10 / (thickness_mm + kerf_mm))Kerf loss % = kerf_mm / (thickness_mm + kerf_mm) x 100Slab waste approx = (1 - pi/4) x log_volume = 21.5%LRF = lumber_volume / log_volume x 100- Mass balance: slab = log − cant (1 − π/4); kerf and edging are sawn out of the cant; lumber = cant − kerf − edging
- Kerf fraction = kerf ÷ (board thickness + kerf)
- The four components sum to 100% of the log — verified across board thicknesses 12–75 mm and kerfs 0.5–5 mm
Formula checked against the sources above by an automated regression test (tests/verify-phase3a.js) that derives each expected value independently of this page. Last reviewed .
FAQ
Wood species data
Density, hardness and movement for 60 timbers
How the calculation works
The round log first becomes a squared cant, and the corners sawn off are slab waste — that alone is about 36% of the log before a single board is cut. Within the cant, every board costs one saw kerf, so thin boards lose proportionally more to dust than thick ones.
Show the formula
Log volume = pi x (D/2)^2 x L. Cant volume = log volume x 2/pi, the largest square that fits inside the round section. Kerf fraction = kerf / (board thickness + kerf). Sawdust = cant volume x kerf fraction. Edging allowance = cant volume x 8%. Lumber = cant - sawdust - edging.The 2/pi cant ratio is exact geometry. The 8% edging allowance is at the low end of the losses reported in FPL GTR-39, where edging and trimming practice is one of the seven factors governing recovery — raise it if your logs carry sweep or wane.
References and what each one provides
- USDA FPL GTR-39 — Factors Determining Lumber Recovery in SawmillingSteele, P.H. (1984). Identifies and quantifies the seven factors that govern how much lumber a log yields, including kerf, edging and trimming practice, saw variation and log taper.Edging and trimming loss, and the effect of kerf width on yield.
Unverified values are marked as such rather than presented as sourced.
Limitations of this calculation
Estimates residue from kerf and conversion assumptions. It does not account for blade type and condition, resaw passes, edging and trimming losses, or moisture content of the residue.
Do not use this for Environmental reporting, waste-transfer documentation, or byproduct sale contracts.
Figures are engineering estimates from the inputs and assumptions shown. Verify against the actual material and, where the result affects structure or safety, against a qualified professional.
How to use this tool
- Enter the log measurements below, then press Calculate.
- Pick your saw type from the dropdown.
- Fill in kerf width, target lumber thickness, log diameter, log length.
- Press Calculate.
Worked example
Common mistakes to avoid
- Forgetting that sawdust volume is fluffed up. Loose sawdust occupies 2–3× the solid wood it came from.
- Estimating dust from board count without counting the number of cuts. Dust comes from kerf × cuts.
- Ignoring moisture when weighing dust for disposal or sale. Wet dust weighs far more.