Freshly cut logs are full of water and can weigh twice as much as the same wood once seasoned. Before you move logs with a tractor, load a trailer or plan a milling job, it is worth knowing how heavy they are. Green density varies a lot by species – a white oak log is about 70% heavier than an eastern white pine log of the same size.
How to use the Log Weight Calculator
- Species
- Custom density
- Small-end diameter
- Large-end diameter
- Log length
- Number of logs
- Every result field is editable: type into Weight of one log or any other result and Log length plus every other field update to match.
Results update as you type, and every field accepts the units shown in its menu.
How it works
Choose the species and moisture state, enter the diameter at each end (inside the bark if possible), the length and the number of logs. The calculator averages the two end areas (Smalian’s formula) to account for taper.
Tips for an accurate estimate
- Sketch the job and split irregular areas into rectangles, circles and triangles before you measure.
- Add a waste allowance – typically 5–10% for simple layouts and 15–20% for diagonal, curved or heavily cut work.
- Check the coverage or yield printed on the product, because sizes and densities vary between manufacturers.
- Buy all units of a finished material (tile, brick, siding) from the same batch so colours match, and keep a few spares for repairs.
- Confirm local prices – quarry, lumber and steel prices vary widely by region and season.
Common mistakes to avoid
- Ordering exactly the calculated amount with no allowance for breakage, offcuts and settlement.
- Forgetting to subtract doors, windows and other openings – or subtracting small ones that still need cutting around.
- Confusing US short tons (2,000 lb) with metric tonnes (1,000 kg) when comparing quotes.
Inputs explained
| Field | What to enter |
|---|---|
| Species | Choose one: Douglas fir (green), Loblolly pine (green), Eastern white pine (green), Ponderosa pine (green) … |
| Custom density | Units: kg/m³, lb/ft³, g/cm³, lb/yd³ |
| Small-end diameter | Units: in, cm, mm, ft, m |
| Large-end diameter | Units: in, cm, mm, ft, m |
| Log length | Units: ft, m, in, yd, cm |
| Number of logs | A number |
What each result means
- Volume of one log = [Log length]×(pi×[Small-end diameter]^2÷4 + pi×[Large-end diameter]^2÷4)÷2
- Total weight = [Weight of one log]×[Number of logs]
- Approx. Doyle log scale (board feet) = (([Small-end diameter]÷0.0254 – 4)÷4)^2×[Log length]÷0.3048×[Number of logs]
Example values
How the main result changes when Log length changes and everything else stays at the example values above:
| Log length (ft) | Total weight (lb) |
|---|---|
| 5 | 447 |
| 7.5 | 670 |
| 10 | 893 |
| 12.5 | 1,117 |
| 15 | 1,340 |
| 20 | 1,786 |
Formula
Volume (Smalian) = length × (A₁ + A₂) ÷ 2, A = π D² ÷ 4Weight = volume × wood density × number of logsWorked example
Inputs — Species: Red oak (green); Custom density: 1,000 kg/m³; Small-end diameter: 14 in; Large-end diameter: 18 in; Log length: 10 ft; Number of logs: 1.
Results — Volume of one log = 14.18 ft³; Weight of one log = 893 lb; Total weight = 893 lb; Approx. Doyle log scale (board feet) = 63.
Key terms
- Smalian's formula
- Log volume = length × average of the two end areas; slightly over-estimates for strongly tapered butt logs.
Frequently asked questions
How much does a green oak log weigh?
About 63 lb/ft³ (1,000 kg/m³), so a 16 in × 10 ft oak log weighs roughly 880 lb.
How long does it take for a log to dry?
Air-drying sawn lumber takes about one year per inch of thickness; whole logs dry very slowly and often check.
What is the Doyle log scale?
A traditional rule for board feet sawn from a log: (D − 4)² ÷ 16 × L, with D the small-end diameter in inches and L in feet.
What formula does the Log Weight Calculator use?
Volume (Smalian) = length × (A₁ + A₂) ÷ 2, A = π D² ÷ 4.