Hoppus Calculator

Quarter-Girth Volume Formula

Input Mode and Units

Measurement Input

Unit System

Wood Species

Log Measurements

Girth at Mid-Length

inches

Measure circumference at the exact mid-point of the log.

Log Length

feet

Number of Logs

logs

Price per Hoppus Foot

USD/Hft

Price per m3 (INR)

INR/m3

Hoppus Volume Results

Hft

Hoppus Feet

Hoppus Metres

True Cubic m3

INR

INR Value

Hoppus Measurements

Quarter Girth (G/4)-

Hoppus vs True ratio78.54%

1 Hft equals m30.02832 m3

Conversions

True cylinder m3-

Board feet equivalent-

USD value-

Formula Trace

About Hoppus Calculator

Standardised by Edward Hoppus in 1736. Calculates log volume using girth at the midpoint. Hoppus feet represent approximately 78.54% of true cylindrical volume, accounting for bark and round log wastage. Still official in UK, widely used in India for imported round wood documentation at Kandla, Nhava Sheva and Mumbai.

Where Used?

India IS 1902UK Timber TradePort of KandlaMumbai Timber YardsImport/Export Documents

Formulas

Hoppus Feet = (G/4)^2 x L / 144 G = girth inches, L = length feetHoppus Metre = (G/4)^2 x L / 10000 G = girth cm, L = length metresTrue volume = Hoppus x (4/pi) = Hoppus x 1.27321 Hoppus foot = 0.02832 m3 | 1 BF = 2359 cm3

FAQ

Why does Hoppus give only 78.54% of true volume?

The quarter-girth formula (G/4)^2 assumes a square cross-section. The ratio of a square inscribed in a circle to the full circle is pi/4 = 0.7854. This built-in deduction accounts for round log waste in sawing.

How is Hoppus used in India today?

IS 1902:2015 defines measurement in cubic metres, but Hoppus is common for imported logs. Indian importers at Gandhidham, Kandla and Nhava Sheva convert: 1 Hft = 0.02832 m3.

Hoppus CalculatorQuarter-Girth Volume Formula