Lumber Yield Calculator - How to Estimate Usable Lumber from Logs

Last updated: 16 Jul 2025 | Author: Brij | Review By: Irshad

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Easily estimate how much usable lumber (board feet) you can produce from logs. Input log size, lumber specs, kerf, and waste to get volume, yield, and efficiency.

Log Length (feet):

Log Diameter (small end, inches):

Number of Logs:

Lumber Thickness:

Lumber Width:

Lumber Length:

Kerf (blade thickness):

Waste Percentage (%):

Lumber Yield Calculation Results

Total Log Volume (board feet):

Estimated Lumber Yield (board feet):

Usable Lumber Yield (after waste):

Yield Percentage (%):

Number of Boards Produced:

Whether you're a sawmill operator or a DIY woodworker, maximizing lumber yield is crucial to efficiency and cost-effectiveness. A Lumber Yield Calculator helps estimate how much usable lumber you can get from your logs based on their dimensions, the lumber specs you need, saw kerf, and waste percentage.

What is Lumber Yield?

Lumber yield refers to the amount of usable lumber (in board feet) you can produce from raw logs. It's influenced by log volume, lumber size, kerf (blade thickness), and cutting strategy.

Formulas Used in the Lumber Yield Calculator

1. Total Log Volume (Board Feet) using Doyle Rule

The Doyle rule is a common method to estimate log volume:

Formula:

$\text{Log Volume} = \left(\frac{(\text{Average Diameter} - 4)^2 \times \text{Log Length}}{16}\right) \times \text{Number of Logs}$

2. Average Diameter (assuming 1" taper per 4 ft)

$\text{Average Diameter} = \frac{\text{Small End Diameter} + (\text{Small End Diameter} + 0.25 \times \text{Log Length})}{2}$

3. Volume per Board

$\text{Board Volume} = \frac{\text{Thickness} \times \text{Width} \times \text{Length}}{12}$

4. Number of Boards

This estimation considers kerf loss and board fit:

$\text{Boards per Log} = \left\lfloor \frac{0.8 \times \text{Average Diameter}}{\text{Width} + \text{Kerf}} \right\rfloor \times \left\lfloor \frac{\text{Log Length}}{\text{Lumber Length}} \right\rfloor$

5. Estimated Yield

$\text{Estimated Yield} = \text{Number of Boards} \times \text{Board Volume}$

6. Usable Yield After Waste

$\text{Usable Yield} = \text{Estimated Yield} \times \left(1 - \frac{\text{Waste \%}}{100}\right)$

7. Yield Percentage

$\text{Yield \%} = \left(\frac{\text{Usable Yield}}{\text{Total Log Volume}}\right) \times 100$

Example Calculation

Let’s walk through an example using your calculator:

Inputs:

Log Length = 12 ft
Small End Diameter = 16 inches
Number of Logs = 2
Lumber Thickness = 1 inch
Lumber Width = 6 inches
Lumber Length = 8 ft
Kerf = 0.125 inches
Waste Percentage = 10%

1. Average Diameter:

$\text{Avg. Diameter} = \frac{16 + (16 + 0.25 \times 12)}{2} = 17.5$

2. Log Volume:

$\text{Volume} = \left(\frac{(17.5 - 4)^2 \times 12}{16}\right) \times 2 = 273.375$

3. Board Volume:

$\text{Board Volume} = \frac{1 \times 6 \times 8}{12} = 4$

4. Number of Boards:

$\text{Boards} = \left\lfloor \frac{0.8 \times 17.5}{6.125} \right\rfloor \times \left\lfloor \frac{12}{8} \right\rfloor \times 2 = 4$

5. Estimated Yield:

$\text{Estimated Yield} = 4 \times 4 = 16$

6. Usable Yield:

$\text{Usable Yield} = 16 \times (1 - 0.10) = 14.4$

7. Yield Percentage:

$\text{Yield \%} = \left(\frac{14.4}{273.375}\right) \times 100 \approx 5.27\%$

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