About ConstructTools

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ConstructTools is a free library of construction calculators for contractors, builders, quantity surveyors, engineering students and homeowners. The goal is simple: give you a fast, honest first estimate — concrete volume, rebar quantities, steel weight, roof area, lumber, paint, tile and more — based on the same formulas engineers use in practice, explained in plain language.

Who is behind the site?

Azeddine El — Structural & BIM engineer

Azeddine El holds a five-year civil engineering degree (2017) and has more than 8 years of experience designing reinforced concrete, steel and timber structures. He runs his own structural engineering consultancy, where he produces structural calculations, reinforcement drawings and steel-structure checks for buildings, industrial canopies and airport facilities. He also develops engineering software, including BIM automation tools and calculation apps.

How we build and check our calculators

Engineering formulas, not guesses. Each tool uses standard geometric and engineering formulas (volumes, section areas, unit weights, slopes) with reference values from recognised sources such as ACI 318, ASTM A615, Eurocode and manufacturer tables.
Worked examples. Every calculator page includes a guide with the formula, a worked example and answers to common questions, so you can check the result by hand.
Regular review. Pages are reviewed and updated; the "last updated" date is shown on every page.
Clear limits. Results are planning estimates. They do not replace a design by a licensed engineer or a quote from a contractor.

Our calculators

Start with the concrete calculator, rebar calculator, steel weight calculator, foundation calculator or roofing calculator, or browse all 18 calculators.

Get in touch

Found an error, need a new calculator or want to work with us? Contact us — we read every message.

Last updated: October 16, 2026