Log Calculator
Calculate log volume (Smalian), board-foot yield by Doyle, Scribner or International rule, and green log weight.
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What this tool does
Calculate log volume (Smalian), board-foot yield by Doyle, Scribner or International rule, and green log weight. Diameters are inside bark at each end. Green density is an editable planning value (many green hardwoods run 50–65 lb/cu ft of solid wood). Board-foot rules estimate sawn yield, never solid volume — the three per-scale tools elsewhere in this category give the same rules one at a time; this tool combines them with true volume and weight.
How to use the Log Calculator
- Enter or select small-end diameter inside bark in in.
- Enter or select large-end diameter inside bark in in.
- Enter or select log length in ft.
- Enter or select log count.
- Enter or select board-foot rule.
- Enter or select green wood density (lb/cu ft).
- Read the calculated result; change any measurement to compare alternatives.
Formula
Smalian volume = length × (small-end area + large-end area) / 2; board feet by the selected rule (small-end diameter); weight = volume × green density
- smallD
- Small-end diameter inside bark (in, before metric conversion)
- largeD
- Large-end diameter inside bark (in, before metric conversion)
- logLength
- Log length (ft, before metric conversion)
- logCount
- Log count
- scale
- Board-foot rule
- greenDensity
- Green wood density (lb/cu ft)
Diameters are inside bark at each end. Green density is an editable planning value (many green hardwoods run 50–65 lb/cu ft of solid wood). Board-foot rules estimate sawn yield, never solid volume — the three per-scale tools elsewhere in this category give the same rules one at a time; this tool combines them with true volume and weight.
Worked example
For log calculator, the following measurements illustrate the exact method: Small-end diameter inside bark: 16; Large-end diameter inside bark: 18; Log length: 16; Log count: 1; Board-foot rule: doyle; Green wood density (lb/cu ft): 55.
Inputs
- Small-end diameter inside bark16 in
- Large-end diameter inside bark18 in
- Log length16 ft
- Log count1
- Board-foot ruleDoyle
- Green wood density (lb/cu ft)55
Result
- Estimated board feet (selected rule)144
- Solid wood volume25.31 cu ft
- Estimated green weight1,391.9 lb
- Board feet per log144
- Volume per log25.31 cu ft
Results explained
- Estimated board feet (selected rule)
- Estimated board feet (selected rule) from the formula above. Diameters are inside bark at each end. Green density is an editable planning value (many green hardwoods run 50–65 lb/cu ft of solid wood). Board-foot rules estimate sawn yield, never solid volume — the three per-scale tools elsewhere in this category give the same rules one at a time; this tool combines them with true volume and weight.
- Solid wood volume
- Solid wood volume from the formula above, expressed in cuft before metric conversion. Diameters are inside bark at each end. Green density is an editable planning value (many green hardwoods run 50–65 lb/cu ft of solid wood). Board-foot rules estimate sawn yield, never solid volume — the three per-scale tools elsewhere in this category give the same rules one at a time; this tool combines them with true volume and weight.
- Estimated green weight
- Estimated green weight from the formula above, expressed in lb before metric conversion. Diameters are inside bark at each end. Green density is an editable planning value (many green hardwoods run 50–65 lb/cu ft of solid wood). Board-foot rules estimate sawn yield, never solid volume — the three per-scale tools elsewhere in this category give the same rules one at a time; this tool combines them with true volume and weight.
- Board feet per log
- Board feet per log from the formula above. Diameters are inside bark at each end. Green density is an editable planning value (many green hardwoods run 50–65 lb/cu ft of solid wood). Board-foot rules estimate sawn yield, never solid volume — the three per-scale tools elsewhere in this category give the same rules one at a time; this tool combines them with true volume and weight.
- Volume per log
- Volume per log from the formula above, expressed in cuft before metric conversion. Diameters are inside bark at each end. Green density is an editable planning value (many green hardwoods run 50–65 lb/cu ft of solid wood). Board-foot rules estimate sawn yield, never solid volume — the three per-scale tools elsewhere in this category give the same rules one at a time; this tool combines them with true volume and weight.
Frequently asked questions
Smalian's formula: average the cross-section areas of the two ends and multiply by length. A 16 ft log tapering 16→18 in holds about 24.6 cu ft of solid wood.
Solid volume × green density. The example log at 55 lb/cu ft weighs about 1,350 lb green — far more than after drying, which is why green logs are a serious lifting problem.
Log rules price the boards a mill can saw out, after kerf, slabs and edging waste. Doyle underestimates small logs especially; International ¼-inch tracks actual recovery most closely.
Whichever your buyer or mill uses — prices are quoted per rule and they are NOT interchangeable. When in doubt, compute all three (the per-scale tools in this category) and expect Scribner between Doyle and International on most logs.
Inside bark, at the small end for board-foot rules. Bark thickness varies by species; when buying, agree the measurement convention before scaling a load.