Timber Cost Estimate Calculator

Example data table

Formula used

• Board feet per piece (imperial): BF = (Thickness(in) × Width(in) × Length(ft)) ÷ 12
• Piece volume (metric): m³ = (Thickness(mm) ÷ 1000) × (Width(mm) ÷ 1000) × Length(m)
• Waste adjustment: Effective Quantity = Pieces × (1 + Waste% ÷ 100)
• Material subtotal: UnitPrice × (Total BF or Total m³ or Effective pieces)
• Pre-tax subtotal: Material + Milling + Treatment + Hardware + Delivery
• Tax: Tax% × Pre-tax subtotal
• Contingency: Contingency% × (Pre-tax subtotal + Tax)
• Grand total: Pre-tax subtotal + Tax + Contingency − Discount

How to use this calculator

1. Select your unit system and pricing basis that matches your supplier quote.
2. Enter the timber size and the number of pieces required.
3. Set waste allowance for offcuts, defects, and on-site changes.
4. Add delivery, milling, treatment, and hardware allowances if needed.
5. Apply tax, contingency, and any discount, then press Calculate.
6. Use CSV or PDF exports to share totals with your team.

Cost drivers you can control

Timber cost shifts most through quantity accuracy, waste control, and the pricing basis in the quote. Enter finished pieces, then apply a realistic waste allowance for defects, offcuts, and rework. If pricing is per board foot, the calculator converts dimensions into board feet, so larger members and longer lengths raise totals. With per cubic meter pricing, volume dominates and small dimension changes add up across an order.

Quantity and waste planning

Waste is not only scrap. It includes trimming for crown, knots, warp, and site adjustments. Framing packages often run 8–15%, while trim or engineered members can be lower when cut lists are controlled. The effective quantity output is what you should purchase, not what you will install. Use it to compare quotes and avoid shortages that trigger reorders.

Unit pricing and measurement checks

Confirm whether unit price includes treatment, milling, or delivery. If pricing is per piece, dimensions still calculate for reporting, but cost follows the piece rate. If pricing is per board foot or per cubic meter, verify nominal versus actual sizes. A “two by four” is often 1.5 in × 3.5 in, which changes board-foot totals. Verify length units when mixing feet and meters.

Allowances that improve realism

Milling, treatment, hardware allowance, delivery, tax, and contingency turn a material quote into a budget-ready estimate. Milling reflects cutting, planing, or shop fabrication priced per board foot or cubic meter. Treatment and hardware allowances are modeled as percentages of material subtotal to stay proportional. Contingency is applied after tax to cover price movement, substitutions, and unforeseen site waste.

Using outputs for purchasing decisions

Review the cost breakdown and average cost per piece. If totals look high, test sensitivity by adjusting waste, changing pricing basis, or separating delivery from material pricing. Export CSV for procurement tracking and generate a PDF for approvals. For structural work, align grade and treatment with drawings and specifications before ordering, then keep the estimate as your baseline for change management.

FAQs

Q1. What price basis should I choose?

Match the basis on your supplier quote. Use per piece for unit-pack pricing, per board foot for lumberyards, and per cubic meter for bulk timber or export quotes.

Q2. How do I pick a waste percentage?

Start with 8–15% for framing, 5–10% for decking, and 3–8% for trim. Increase waste for complex layouts, long members, or uncertain site conditions.

Q3. Does the calculator use nominal or actual sizes?

It uses the dimensions you enter. If your design uses nominal sizes, convert to actual dimensions used by your supplier before calculating to avoid underestimating board feet and cost.

Q4. What does milling rate represent?

Milling rate is an added cost for cutting, planing, drilling, or shop preparation. Enter it per board foot in imperial mode or per cubic meter in metric mode.

Q5. Can I estimate treated timber premiums?

Yes. Add a treatment allowance percent to model the uplift on material subtotal, or include treatment in the unit price and set the allowance to zero.

Q6. How are discount, tax, and contingency applied?

Tax is applied to the pre-tax subtotal. Contingency is calculated after tax. Discount is applied last, which keeps the estimate conservative for purchasing approvals.