Disclaimer

Last updated: 23 September 2026

BuildMetricLab provides free online construction calculators, material estimators, and unit converters. The results they produce are estimates for educational and planning purposes only. They are not, and must not be treated as, professional advice, or a substitute for a qualified contractor's quote, an engineer's calculation, or a building approval or permit.

What this means in practice

• Quantities are estimates. Every real-world job has site-specific conditions (wastage, cut-offs, substrate, access, crew) that change what you actually need. Verify every quantity with your supplier or contractor before ordering. We recommend building in additional contingency on top of the wastage assumptions shown.
• Costs are illustrative. Prices in the calculators are your own inputs; where a calculator starts from a default price, that figure is only a placeholder. Actual prices vary by country, region, supplier, quantity and market conditions, and may or may not include sales tax, VAT or GST. Always get written quotes.
• No structural or code advice. Calculators that touch beams, lintels and headers, foundations and footings, loads, fall or slope, drainage, electrics, gas, plumbing, or heating and cooling sizing are screening tools only. Designs that affect structural integrity, safety, or building-code compliance must be signed off by a qualified, licensed professional where the work is being done.
• Approvals and permits. Many works need consent before they start. This site does not determine whether any specific work needs one — that is the owner's or contractor's legal responsibility under local law.
• No warranty. Calculators are provided "as is". Formulas are documented on each tool page so you can check the method. We test actively but cannot guarantee every edge case. To the fullest extent permitted by law, all express and implied warranties, including merchantability and fitness for a particular purpose, are disclaimed. Use of this site is at your own risk.

Codes, approvals and licensed trades by region

What applies depends on where the work is done. As a guide:

• United Kingdom: Building Regulations approval, planning permission, Party Wall notices or Competent Person Scheme certification may be needed. Gas work must be done by a Gas Safe registered engineer, and electrical work by a competent electrician (for example one registered with NICEIC); structural designs need a chartered structural engineer.
• United States: the International Residential Code (IRC), International Building Code (IBC), plumbing and mechanical codes (IPC, IMC), the National Electrical Code (NEC / NFPA 70) and the International Energy Conservation Code (IECC) apply as adopted and amended by your state, county or city. Permits, inspections, zoning or HOA approval may be required, and work must be signed off by professionals licensed in that jurisdiction. Refrigerant handling requires an EPA Section 608 certified technician.
• Australia: the National Construction Code (NCC) and relevant Australian Standards (AS/NZS) apply. Building approval, a development application, an owner-builder permit or a Bushfire Attack Level (BAL) assessment under AS 3959 may be needed, and gas and electrical work is for licensed trades only. Requirements vary between states and territories.
• Canada: the National Building Code of Canada as adopted and amended by each province and territory (for example the Ontario Building Code, the BC Building Code or the Code de construction du Québec), with the relevant CSA standards, applies. Structural work may need a professional engineer (P.Eng.), and gas and electrical work is for licensed trades.

Your consumer rights

Nothing in this disclaimer limits your rights under the Consumer Rights Act 2015 (UK), the Australian Consumer Law (Schedule 2 of the Competition and Consumer Act 2010), the consumer-protection legislation of your Canadian province or territory, or the consumer-protection law of your US state, where those rights cannot be excluded by contract.

When to consult a professional

Always consult a suitably qualified, licensed professional before:

• Any structural alteration (removing walls, cutting joists or rafters, new openings, beam sizing, or foundation and underpinning work).
• Gas, electrical, plumbing, mechanical, refrigerant or hot-water work.
• Work near a boundary, party wall, easement or protected (listed, heritage or historic-district) property.
• Drainage that discharges to a public sewer, storm drain or watercourse.
• Building in a bushfire-prone, flood, termite-management or frost-susceptible area.
• Anything involving asbestos, lead paint, mould or other regulated hazardous materials.

If in doubt, don't. Get a professional.