Round Timber Calculator
Calculate round timber cubage: logs, thinwood, pulpwood. Volume by diameter and length, pieces to m³ and back.
Diameter at the thin end of the log in centimeters — the standard measurement
Length of the log in meters — typically 4, 6, or 8 m
How many logs in the batch
Calculation formula
V₁ = π × (D/100)² ÷ 4 × L; V_total = V₁ × N
D — top-end diameter in cm, L — log length in m, N — number of logs. The log is treated as a cylinder; the actual cubage by GOST 2708-75 tables is slightly larger because of the natural taper from butt to top.
About the round timber calculator
The round timber calculator computes log cubage from the top-end diameter and the length. It works for sawlogs, thinwood, pulpwood and posts — any round wood that is sold and graded by its thin-end diameter.
The math uses the geometric volume of a cylinder. This is convenient for quick estimates on the felling site, when paying for a logging truck, or when buying timber for a log house. For official acceptance, GOST 2708-75 (round timber volume tables) gives a slightly larger figure because it accounts for the taper of the trunk toward the butt.
All calculations run in your browser — nothing is sent to a server. Run as many estimates as you need: a single log, a truckload, or a full shipment.
Calculator benefits
Single log and batch volume
See both the volume of one log and the total cubic meters of the whole batch
Top-end measurement
Calculation uses the top-end diameter — the standard way logs are graded at sawmills and timber yards
Works for any round wood
Sawlogs, thinwood, pulpwood, posts — the same formula applies to all types of round timber
Frequently asked questions
How does GOST 2708-75 differ from the geometric formula?
GOST 2708-75 is a set of round timber volume tables that account for trunk taper — a log is thicker at the butt than at the top. The geometric formula π × D² ÷ 4 × L treats the log as a perfect cylinder and usually gives 5–15% less volume than the table value. The geometric estimate is fine for quick checks and for sales 'by the thin end'; for official intake and shipping documents use the GOST tables.
Does cubage differ between softwood and hardwood?
Geometric volume does not depend on species — a cubic meter of pine, spruce, birch or oak is calculated the same way. What differs is density and weight: a cubic meter of dry pine weighs about 470 kg, spruce 450 kg, birch 650 kg, oak 700 kg. GOST 2708-75 also uses common volume tables without separate species coefficients.
How do you measure log diameter correctly?
Diameter is measured at the top end — the thin face of the log — with bark excluded. If the face is oval, take the average of two perpendicular measurements and round to the nearest even centimeter per GOST rules. Length is measured along the shortest side, not along the slant. This is the standard procedure at sawmills, timber yards and for logging-truck delivery.
How many logs are in a cubic meter?
It depends on diameter and length. A 24 cm × 6 m log gives about 0.27 m³, so roughly 3.7 logs fit in 1 m³. A 14 cm × 4 m thinwood log is 0.06 m³, about 16 per cubic meter. Enter your dimensions and quantity above and the calculator will compute the batch cubage automatically.