Wood Weight Calculator UK: Timber Density, Weight Per Metre and Structural Sizes
Work out how much a length, pack or delivery of timber weighs in kilograms. This page uses UK sizes in millimetres, lists the BS EN 338 densities behind C16 and C24, shows the published figures for common species, and gives ready-made tables for weight per metre, kilograms per cubic metre and the effect of moisture.
Quick Answer
UK timber weight is calculated as Weight (kg) = Width (m) x Depth (m) x Length (m) x Density (kg/m3), enter your dimensions in millimetres and metres, choose a species or structural grade (C16/C24), and get an instant weight in kilograms, useful for van payload checks, joist load calculations, or simply working out how much a delivery will weigh.
Wood Weight Calculator UK: Timber Density, Weight Per Metre and Structural Sizes
Enter your values below for an instant result, then see the formula, worked example, and common mistakes.
Enter your timber dimensions in metres/millimetres, then click calculate.
Check the Estimate Against a Real Weight
Best Crane Scale for Weight Checks
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Published densities are averages. Two boards cut from the same species can differ noticeably, and a board that has sat in a damp yard weighs more than the kiln-dried figure. Weigh one length on a scale and compare it with the calculator figure for the same piece. If your real piece is 5% heavier, scale the pack total up by the same 5%.
How to Use This Calculator
UK softwoods (Scandinavian redwood/pine, spruce/whitewood, Douglas fir) generally range 370-530 kg/m3 kiln-dried; UK hardwoods (European oak, beech, ash) generally run 580-760+ kg/m3. C16 and C24 are structural strength grades with their own TRADA-published mean densities (370 and 420 kg/m3 respectively).
Common UK timber lengths are sold in 0.3 m increments, commonly 2.4, 3.0, 3.6, 4.2, and 4.8 m.
UK carcassing sizes are typically specified as e.g. 47×100, 47×150, or 47×225 mm; joinery/PAR timber uses smaller finished sections like 25×50 or 50×100 mm.
Kiln-dried timber at roughly 15% moisture content (MC) is the standard reference condition for UK density tables and most purchased sawn timber. Green (freshly felled, unseasoned) timber can weigh 30-60% more due to retained water.
Multiply by quantity to check a full timber pack’s weight against a van’s payload rating or to plan a delivery.
Formula
Weight (kg) = Width (m) x Depth (m) x Length (m) x Density (kg/m3). UK timber sizes are specified in millimetres, so divide width and depth by 1,000 before multiplying. For structural carcassing timber, C16 and C24 refer to strength grades (not species) with published mean densities of 370 kg/m3 and 420 kg/m3 respectively (TRADA, kiln-dried regularised timber).
Reference Table: UK Timber Density by Species/Grade
| Species/Grade | Density (kg/m3) | Type | Typical UK use |
|---|---|---|---|
| Western Red Cedar | 370 | Softwood | Cladding, garden buildings |
| C16 (structural grade) | 370 | Softwood grade | Stud walls, general carcassing |
| Spruce/Whitewood | 450 | Softwood | Joinery, carcassing |
| C24 (structural grade) | 420 | Softwood grade | Floor joists, rafters (higher strength) |
| Scandinavian Redwood (Pine) | 510 | Softwood | Structural, joinery, flooring |
| Douglas Fir | 530 | Softwood | Structural beams, decking |
| European Larch | 590 | Softwood | Cladding, decking, fencing |
| Black Walnut (American) | 640 | Hardwood | Furniture, veneer |
| European Oak (joinery grade) | 720 | Hardwood | Flooring, beams, furniture |
| American White Oak | 760 | Hardwood | Flooring, furniture, barrels |
| Balau | 845 | Hardwood | Decking, heavy outdoor use |
Sourced Density Check: Calculator Value vs Published Figure
The dropdown uses rounded UK trade values. The table below sets each against a published reference so you can see how far apart they are. Published species figures are at 12% moisture content, the calculator values at about 15%, so small differences are expected.
| Timber | Calculator (kg/m3) | Published (kg/m3) | Source |
|---|---|---|---|
| C16 softwood | 370 | 370 (mean density) | BS EN 338 strength class table |
| C24 softwood | 420 | 420 (mean density) | BS EN 338 strength class table |
| Western red cedar | 370 | 370 | The Wood Database |
| Scots pine (redwood) | 510 | 550 | The Wood Database |
| Douglas fir | 530 | 510 | The Wood Database |
| European larch | 590 | 575 | The Wood Database |
| Balau | 845 | 850 | The Wood Database |
Weight Per Metre and Per 2.4 m Length: C16 and C24
Calculated from section area x density, using the BS EN 338 mean densities (370 kg/m3 for C16, 420 kg/m3 for C24). Sizes are nominal; planed timber is slightly smaller and lighter.
| Size (mm) | C16 kg/m | C24 kg/m | C16, 2.4 m | C24, 2.4 m |
|---|---|---|---|---|
| 38 x 89 | 1.25 | 1.42 | 3.0 kg | 3.4 kg |
| 47 x 75 | 1.30 | 1.48 | 3.1 kg | 3.6 kg |
| 47 x 100 | 1.74 | 1.97 | 4.2 kg | 4.7 kg |
| 47 x 150 | 2.61 | 2.96 | 6.3 kg | 7.1 kg |
| 47 x 200 | 3.48 | 3.95 | 8.3 kg | 9.5 kg |
| 47 x 225 | 3.91 | 4.44 | 9.4 kg | 10.7 kg |
| 75 x 225 | 6.24 | 7.09 | 15.0 kg | 17.0 kg |
| 100 x 100 | 3.70 | 4.20 | 8.9 kg | 10.1 kg |
Timber-frame walling, studwork and joists are all built from these sections, so adding up the lengths and multiplying by the kg per metre gives a quick estimate of frame weight.
Cubic Metres to Kilograms: Quick Table
Timber is often bought by the cubic metre, but vans and lifting gear are rated in kilograms. Multiply volume by density.
| Volume | Softwood 510 kg/m3 | European oak 720 kg/m3 | Balau 845 kg/m3 |
|---|---|---|---|
| 1 m3 | 510 kg | 720 kg | 845 kg |
| 2 m3 | 1,020 kg | 1,440 kg | 1,690 kg |
| 4 m3 | 2,040 kg | 2,880 kg | 3,380 kg |
| 6 m3 | 3,060 kg | 4,320 kg | 5,070 kg |
Going the other way, one tonne of timber occupies about 2.70 m3 of C16 (1,000 / 370), 2.38 m3 of C24, 1.96 m3 of 510 kg/m3 softwood, or 1.39 m3 of 720 kg/m3 oak. A hardwood load that looks small can still use up a van’s payload quickly.
Floorboards and Sleepers: Weight Per Square Metre and Per Piece
For boards, weight per square metre is simply thickness in metres x density. For sleepers, multiply the section by length. Both use the dry densities in the calculator; treated or wet sleepers weigh more.
| Item | Volume | At 510 kg/m3 | At 720 kg/m3 |
|---|---|---|---|
| 19 mm board, per m2 | 0.019 m3 | 9.7 kg | 13.7 kg |
| 22 mm board, per m2 | 0.022 m3 | 11.2 kg | 15.8 kg |
| 25 mm board, per m2 | 0.025 m3 | 12.8 kg | 18.0 kg |
| 200 x 100 mm sleeper, 2.4 m | 0.048 m3 | 24.5 kg | 34.6 kg |
| 200 x 150 mm sleeper, 2.4 m | 0.072 m3 | 36.7 kg | 51.8 kg |
How Moisture Content Changes the Weight
Water adds weight on top of the dry wood. Relative to timber at 15% moisture content (the calculator baseline), weight scales roughly with (1 + MC) / 1.15. This simple relation ignores the small change in volume as timber dries below fibre saturation, so treat it as an estimate.
| Moisture content | Weight vs 15% MC | Example: 100 kg at 15% |
|---|---|---|
| 12% | 0.97x | 97 kg |
| 15% | 1.00x | 100 kg |
| 20% | 1.04x | 104 kg |
| 30% | 1.13x | 113 kg |
| 50% | 1.30x | 130 kg |
| 80% | 1.57x | 157 kg |
The calculator’s green option adds 45%, which works out to roughly 67% moisture content (1.45 x 1.15 = 1.67), between the 50% and 80% rows above. Use the table if you know the real reading from a moisture meter.
Common Mistakes to Avoid
- Confusing C16/C24 (strength grades) with a species, they describe structural strength classification for graded softwood, most commonly Scandinavian redwood or European spruce, not a specific timber species.
- Using nominal (sawn) size instead of actual finished size for PAR (planed all round) joinery timber, sawn 50×100 mm typically finishes closer to 45×95 mm after planing, which reduces the true weight slightly.
- Applying kiln-dried density values to green (unseasoned) timber, green timber, especially hardwood, can weigh 30-60% more due to retained moisture, which matters for both transport payload and structural dead-load calculations before the timber has dried in place.
- Ignoring pack weight limits when ordering structural timber for delivery or self-collection, multiply per-metre weight by quantity and length, and check against your vehicle’s payload before loading a full pack.
When the Estimate May Be Wrong
Density figures represent typical values for kiln-dried timber at approximately 15% moisture content, the standard condition for purchased UK sawn timber, and can vary by growth region, individual board density, and specific mill/supplier. For structural design (joist sizing, beam spans), always use the specific grade stamp, span tables, or a structural engineer’s calculation rather than average species density alone.
FAQs
How do you calculate timber weight in the UK?
Multiply width in metres by depth in metres by length in metres by the timber’s density in kg per cubic metre, since UK timber dimensions are given in millimetres, divide each by 1,000 first.
What is the difference between C16 and C24 timber?
C16 and C24 are UK structural strength grades for softwood timber, not species, C24 is the higher-strength grade with a higher mean density (420 kg/m3) compared to C16 (370 kg/m3), used where greater structural performance is required, such as longer floor joist spans.
How much does a pack of timber joists weigh?
Multiply the per-metre weight (from width, depth, and density) by the joist length and then by the number of joists in the pack, for example, 50 joists of 47x150mm C16 at 4.8m each weigh roughly 626 kg total.
Does moisture content affect timber weight significantly?
Yes, green (unseasoned) timber can weigh 30 to 60% more than the same timber once kiln-dried to the standard 15% moisture content used in most UK density reference tables.
How much does 1 cubic metre of timber weigh?
About 370 kg for C16 softwood, 510 kg for Scots pine and around 720 kg for European oak at roughly 15% moisture content. For example, 6 m3 of 720 kg/m3 hardwood weighs about 4,320 kg.
How much does a 2.4 m length of 47 x 100 mm C24 timber weigh?
0.047 x 0.100 x 2.4 = 0.01128 m3, and at 420 kg/m3 that is about 4.7 kg.
Sources and Methodology
The calculator uses typical kiln-dried (about 15% moisture content) trade densities. Cross-checks used for this page: the C16 (370 kg/m3) and C24 (420 kg/m3) mean densities come from the BS EN 338 strength-class table, as reproduced by the Engineering ToolBox structural softwood strength-class page; the species figures in the sourced-density table come from The Wood Database entries for Scots pine, European larch, Douglas fir, western red cedar and balau, each quoted at 12% moisture content. The moisture table is a straight calculation, not a measured result.
- Engineering ToolBox: structural softwood strength classes (BS EN 338)
- The Wood Database: Scots pine, European larch, Douglas fir, western red cedar, balau
- Moisture relation: the Forest Products Laboratory Wood Handbook gives density at moisture content M as 1,000 x specific gravity x (1 + M/100) kg/m3.
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