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37 Formulas

Log Measurement Formulas

Log rules and round-timber volume equations.

Scribner Log Rule

Open the Scribner Log Rule →
Scribner Log Rule
Scribner = (0.79 x D^2 - 2 x D - 4) x (L / 16) BF, D=in DIB, L=ft
Used in Scribner Log Rule
Scribner Log Rule
Decimal C = floor(BF / 10) x 10 official USFS rounded form
Used in Scribner Log Rule

Doyle Log Rule

Open the Doyle Log Rule →
Doyle
BF = ((D - 4)^2 / 16) x L D = DIB inches, L = length feet
Used in Doyle Log Rule
Scribner
BF = (0.79 x D^2 - 2xD - 4) x (L/16)
Used in Doyle Log Rule
International
BF = (0.905 x (D/2)^2 - D) x (L/16)
Used in Doyle Log Rule
IS 1902 India
V = pi x (D/200)^2 x L m3, D in cm, L in m
Used in Doyle Log Rule
Conversion
1 m3 = 423.78 BF | 1 BF = 2359 cm3
Used in Doyle Log Rule

Huber Formula

Open the Huber Formula →
Huber
V = A_mid x L = pi x (D_mid/200)^2 x L D in cm, L in m
Used in Huber Formula
Weight
W = V x density (kg/m3)
Used in Huber Formula
Hoppus feet
Hft = V / 0.02832
Used in Huber Formula

Sawdust Waste Estimator

Open the Sawdust Waste Estimator →
Sawdust Waste Estimator
Boards per pass = floor(D_cm x 10 / (thickness_mm + kerf_mm))
Used in Sawdust Waste Estimator
Sawdust Waste Estimator
Kerf loss % = kerf_mm / (thickness_mm + kerf_mm) x 100
Used in Sawdust Waste Estimator
Sawdust Waste Estimator
Slab waste approx = (1 - pi/4) x log_volume = 21.5%
Used in Sawdust Waste Estimator
Sawdust Waste Estimator
LRF = lumber_volume / log_volume x 100
Used in Sawdust Waste Estimator

Bark Deduction Tool

Open the Bark Deduction Tool →
Bark Deduction Tool
Bark thickness each side = OB_diameter x bark_factor / 200
Used in Bark Deduction Tool
Bark Deduction Tool
UB diameter = OB diameter - 2 x bark_thickness
Used in Bark Deduction Tool
Bark Deduction Tool
Volume OB = pi x (D_OB_mid / 200)^2 x L (Huber method)
Used in Bark Deduction Tool
Bark Deduction Tool
Volume UB = pi x (D_UB_mid / 200)^2 x L
Used in Bark Deduction Tool
Bark Deduction Tool
Bark volume % = (V_OB - V_UB) / V_OB x 100
Used in Bark Deduction Tool

Hoppus Calculator

Open the Hoppus Calculator →
Hoppus Calculator
Hoppus Feet = (G/4)^2 x L / 144 G = girth inches, L = length feet
Used in Hoppus Calculator
Hoppus Calculator
Hoppus Metre = (G/4)^2 x L / 10000 G = girth cm, L = length metres
Used in Hoppus Calculator
Hoppus Calculator
True volume = Hoppus x (4/pi) = Hoppus x 1.2732
Used in Hoppus Calculator
Hoppus Calculator
1 Hoppus foot = 0.02832 m3 | 1 BF = 2359 cm3
Used in Hoppus Calculator

Standing Tree Volume

Open the Standing Tree Volume →
IS 4213 India
V = (pi/4) x DBH^2 x H x f DBH in metres, H in metres
Used in Standing Tree Volume
Basal Area
BA = pi x (DBH/200)^2 m2, DBH in cm
Used in Standing Tree Volume
Standing Tree Volume
QS boards per quarter = floor(R x 10 / (thickness + kerf))
Used in Standing Tree Volume

Smalian Formula

Open the Smalian Formula →
Smalian
V = ((A1 + A2) / 2) x L A = pi x (D/200)^2 D in cm, L in m
Used in Smalian Formula
Huber
V = A_mid x L A_mid at midpoint
Used in Smalian Formula
Newton
V = (A1 + 4 x A_mid + A2) / 6 x L most accurate
Used in Smalian Formula

International Log Rule

Open the International Log Rule →
Per 8-ft section
BF = (0.905 x (D_s/2)^2 - D_s) x (L_s/16)
Used in International Log Rule
International Log Rule
D_s = diameter at each 8-ft section (adjusted for taper)
Used in International Log Rule
International Log Rule
Full log = sum of all 8-ft sections
Used in International Log Rule

Log Taper Calculator

Open the Log Taper Calculator →
Log Taper Calculator
Taper = (D_large - D_small) / L cm per metre
Used in Log Taper Calculator
Log Taper Calculator
Form factor f = V_huber / V_cylinder
Used in Log Taper Calculator
IS 1902 Class 1
taper <= 0.5 cm/m (slight)
Used in Log Taper Calculator
IS 1902 Class 2
0.5 to 1.5 cm/m (moderate)
Used in Log Taper Calculator
IS 1902 Class 3
> 1.5 cm/m (excessive)
Used in Log Taper Calculator

Common questions

Where do these formulas come from?

Every formula on this page comes from a published source — standards, handbooks or long-established trade rules for log scaling and timber measurement. The source is named next to each formula. Nothing here is invented by us.

Can I use these formulas in my own spreadsheets or software?

Yes. The formulas themselves are public knowledge and free to use anywhere. If our page helped you, a link back is appreciated but not required.

Are the calculators on this site using these exact formulas?

Yes. Each calculator runs the formula shown here, and automated tests check the results against worked examples from the original sources before anything goes live.