Calculate lumber quantities

What does this calculator do?

The lumber calculator gives you board count, m³ volume, total running metres, weight and material cost for your lumber project — all in one step, all in the browser, all local without server roundtrip. It knows six wood species with real density values (spruce 470 to ash 720 kg/m³), five project types with project-specific wastage corridors, and DIN 4074-1 sortier-classes mapped to DIN EN 338 strength classes.

Five differentiation features no other online calculator integrates this way:

1. Project-specific wastage corridors instead of a single flat number. Most online lumber calculators show a single “Wastage %” field with default 10 — regardless of whether you’re building battens (3–7 %), wall sheathing (5–10 %), flooring (8–12 %), terrace decking (10–15 %) or formwork (15–22 %). The calculator knows the use case and adapts the recommended corridor. The slider stays freely editable.
2. DIN 4074-1 sortier-classes + DIN EN 338 strength-class mapping as an info card next to the species. S10 maps to C24, S13 maps to C30, LS10 maps to D30. Market standard for load-bearing members is S10/C24 — the calculator shows the mapping but does not replace structural analysis per Eurocode 5.
3. Statically embedded Q1/2026 price corridors sourced from Destatis producer-price index February 2026 and B+L timber-construction market report. Spruce 500–600 €/m³, oak 600–714 €/m³ etc. No live fetch, no ads, no affiliate links — “Valid Q1/2026” timestamp stays visible, the €/m³ value is editable.
4. Bill-of-materials export as Markdown or CSV. One click copies the bill to your clipboard — Markdown for the estimate request email, CSV for spreadsheet import. Sorted by board type and species, with all relevant columns.
5. Pure-client and offline-capable — the calculation runs entirely in the browser, no data leaves your device, no account needed.

The calculator follows German timber-construction standards DIN 4074-1 (visual sorting of softwood lumber) and DIN EN 338 (strength classes for structural lumber). For structural design DIN EN 1995 (Eurocode 5) applies — the calculator delivers quantities, not the structural design.

How is lumber quantity calculated?

The base formula depends on the input mode. In count mode you enter board dimensions and the count:

Volume per board = length × width × thickness
Total volume     = count × volume per board × (1 + wastage %)
Total lfm        = count × length
Weight           = total volume × density (kg/m³)

Worked example — 100 wall-sheathing boards 200 × 12 × 2 cm spruce:

• Volume per board = 2.00 m × 0.12 m × 0.02 m = 0.0048 m³
• Wait — verify the math: at 200 × 12 × 2 cm the dims in metres are 2 × 0.12 × 0.02 = 0.0048 m³ per board. Hundred boards = 0.48 m³ at zero wastage. At 10 % wastage, 110 boards equal 0.528 m³. The earlier “0.048 m³ per board” reading mixed two different decimal placements — careful. The calculator handles unit conversion deterministically.
• Total running metres = 110 × 2 = 220 lfm
• Weight = 0.528 m³ × 470 kg/m³ (spruce) ≈ 248 kg

Note: the working example assumes a thin 2-cm sheathing board. Thick joist or beam sections (e.g. 6 × 12 cm) of the same length yield 0.0144 m³ per board, three times more.

In area mode you enter the area to cover and the board dimensions:

Boards (net) = ceil(area / (length × width))
Total volume = boards × volume per board × (1 + wastage %)

Worked example — 25 m² wall with 200 × 12 cm boards:

• Coverage per board = 2 m × 0.12 m = 0.24 m²
• Boards net = ⌈25 / 0.24⌉ = ⌈104.17⌉ = 105 boards
• With 7 % wastage = ⌈105 × 1.07⌉ = 113 boards
• Order volume = 113 × 0.0048 = 0.542 m³

Which six wood species does the calculator support?

Species	Density (kg/m³)	Sortier-class	Strength class	Primary use
Spruce	470	S10	C24	Standard structural lumber, roof trusses, sheathing
Pine	510	S10	C24	Pressure-treated for exterior, terrace substructure
Douglas fir	540	S10	C24	Structural carpentry, CLT lamellas
Larch	590	S10	C24	Façades, terrace decking (naturally durable)
Oak	690	LS10	D30	Half-timber restoration, solid-wood stairs, floorboards
Ash	720	LS10	D30	Highly stressed members, treads, tool handles

The sortier-class is a market-standard suggestion — the actual class of the supplied lumber depends on each piece and is stamped on the delivery note. S10/C24 covers ~90 % of residential structural carpentry. S13/C30 is the higher class for structurally demanding applications such as long-span purlins or high-load posts.

Which wastage corridor fits which project?

The wastage corridors are not marketing flat-rates but project-specific:

Project type	Wastage corridor	Default	Rationale
Battens	3–7 %	5 %	Simplest straight cuts, almost no angled trim
Wall sheathing	5–10 %	7 %	Few angled cuts, corner trim stays straight
Floor decking	8–12 %	10 %	Cuts at doors, radiators, wall transitions
Terrace decking	10–15 %	12 %	Post and railing angled cuts
Formwork (concrete)	15–22 %	18 %	Rough cuts, but reusable — long-term corridor drops

When switching project types the calculator loads project-appropriate default board dimensions and wastage corridor. You can override both at any time — defaults are starting points, not constraints.

DIN 4074-1 and DIN EN 338 — what do sortier and strength classes mean?

DIN 4074-1 is the German standard for visual sorting of softwood lumber by load-bearing capacity. It defines three classes for softwood (S7 — low, S10 — market standard, S13 — high) and for hardwood (LS7/LS10/LS13). Visual sorting examines knots, cracks, grain slope, warping and discolouration.

DIN EN 338 is the European standard for structural-lumber strength classes. Softwood classes are labelled C (Coniferous), hardwood classes D (Deciduous). The number equals the characteristic bending strength in N/mm² (e.g. C24 = 24 N/mm²).

The mapping is normative:

• S7 → C16 (base class, secondary members)
• S10 → C24 (standard class for load-bearing members, market standard)
• S13 → C30 (higher class for structurally demanding applications)
• LS10 → D30 (standard hardwood class)
• LS13 → D40 (higher hardwood class)

The calculator shows this mapping as an info card. Important: this is a standards lookup, not a structural design. Load-bearing members require a Eurocode 5–compliant structural design by a licensed structural engineer.

Q1/2026 price corridors — where do the numbers come from?

The price corridors come from two official sources:

1. Destatis producer-price index February 2026 for softwood lumber (+12.1 % year-over-year for industry averages, +7.8 % for spruce versus February 2025).
2. B+L timber-construction market report Q1/2026 for industry-specific sawmill list prices by species and sortier-class.

The values are statically embedded in the calculator — no live API, no runtime network dependency. This has two consequences: (a) the calculator works offline and without tracking risk, (b) for large price drifts (>15 % vs. quarterly average) the corridor must be refreshed manually. Refresh cadence: annual, as soon as Destatis Q4 data is available.

Species	Corridor (€/m³ incl. VAT)	Midpoint
Spruce	500–600	540
Pine	520–620	560
Douglas fir	580–680	620
Ash	580–700	640
Larch	600–720	660
Oak	600–714	660

The €/m³ value is editable in the calculator. If you have a concrete sawmill quote, enter it — the calculator immediately reflects the real price.

Bill-of-materials export — Markdown or CSV?

The calculator delivers the bill of materials in two clipboard-ready formats:

• Markdown for the email to the sawmill dealer (“this is what I need”), for your project notebook entry or as an attachment to a permit application. Readable as text, formatted as a list with species, board dimensions, count, total m³ and weight.
• CSV for import into Excel, LibreOffice Calc or Google Sheets. One row per board type with all measurement and quantity values, including €/m³.

Both exports respect the UI language: DE bill uses comma decimal and semicolon CSV separator; EN bill uses dot decimal and comma separator. Export runs in the browser via the Clipboard API — no file uploads to a server, no files saved to disk.

What does the calculator NOT do?

Deliberately left out to keep scope and liability clear:

• No structural analysis / no member design. Rafter cross-section for snow load, purlin dimensioning, post buckling check — all Eurocode 5 domain, belongs to a structural engineer.
• No cutting-stock optimisation. A 1-D cutting-stock solver distributing length lists onto standard stock lengths — could be a separate tool but is out of scope for the quantity calculator.
• No BIM/IFC import. Integration with CAD/BIM stacks belongs to professional tools, not a DIY quantity calculator.
• No live price API. Lumber prices vary regionally and daily — a live API would force a server dependency and break the privacy promise. Static Q1/2026 corridors are sufficient for order-of-magnitude estimates.
• No firewood mode. Festmeter, stacked m³, loose m³ — different units, different use case. Phase-2 candidate as a separate firewood calculator.
• No affiliate links to building-material chains. The calculator does not recommend a dealer and does not collect contact data. You take the bill of materials to your local sawmill or building-material supplier of choice.

Which building tools are related?

For complementary tasks around construction and renovation projects: Roof-Area Calculator for seven roof forms with DIN 18338 aufmaß logic, Screed Calculator for floor-build-up quantities, Masonry Calculator for brick and mortar requirements per Eurocode 6, Concrete Calculator for foundation and slab quantities, and Insulation Calculator for GEG 2024-compliant insulation thickness.

Specialised modules for cutting-stock optimisation, CLT/cross-laminated timber quantities and firewood stacked-m³ conversion are on the Phase-B roadmap, pending real search-demand data.

Frequently Asked Questions

The frontmatter of this page lists ten FAQ entries with schema.org/FAQPage markup, sourced from top Google “People also ask” patterns for lumber-quantity topics. Answers address the question in the first 10 words directly — voice-search-optimised for smart speakers and AI search assistants.