Spike's Calculators

Measurement of log volume under bark - SDC's instructions for estimating timber volume.

All diameter measurements are measured under bark.

*Top-butt measurement may be used for all tree species on logs with a top diameter of ≥ 3 cm and length ≤ 6.5 m*

The diameter is measured 10 cm from each end of the log, with the exception of the butt end of a butt log, where the measurement is taken 50 cm from the end.

V = π ÷ 4 * L[cDl² + (1- c)Dt²]where:

V = the log volume in cubic metres

L = length of the log in metres

c = constant

Dt = small end diameter taken 10 cm from end of log

Dl = large end diameter taken 10 cm from end of log/ taken 50 cm from the end of a butt log

- the log length in metres
- top end diameter measured 10 cm in from top end of log in centimetres
- butt end diameter measured 10 cm in from butt end of log or 50 cm butt end of a butt log

- volume of log in cubic metres

*Top measurement may be used on all tree species, regardless of diameter and length. *

The top diameter is measured 10 cm from the top end of the log.

V = π ÷ 4 * L * Dt²where:

V = the log volume in cubic metres

L = length of the log in metres

Dt = the small end diameter measured 10 cm from the top end of log

- the log length in metres
- top end diameter measured 10 cm in from top end of log

- volume of log in cubic metres

*Mid-point measurement may be used on all tree species, regardless of diameter and length. *

V = π ÷ 4 * L * Dm²where:

V = the log volume in cubic metres

L = length of the log in metres

Dm = the mid-point diameter

- the log length in metres
- diameter measured at the mid length of the log

- volume of log in cubic metres

- Brereton Log Rule - Metric Measurements
- Burt's Quarter Girth Method
- Chinese National Standard
- Cubic Metre Rule
- Francon Measure
- Hoppus Rule
- Huber's Formula
- Huber's Formula - Metric
- Ireland - Log Volume Measurement
- Japanese Agricultural Standard (JAS)
- Manitoba - Cubic Method
- Newton's Formula
- Nova Scotia Cubic Metre Log Scale
- Pressler's Cubic Foot Formula
- Smalian's Formula - Metric
- Smalian's Formula - Imperial
- Solid Volume of a Log
- Spike's Rule
- Swedish Log Volume Calculation
- Swedish Log Volume Calculation Method One
- Swedish Log Volume Calculation Method Two
- Swedish Log Volume Calculation Method Three
- William Klemme