Ethan Zhang
Product builder and quality-assurance maintainer for the free Concrete Calc Pilot estimating software.
What the product builder and QA maintainer is responsible for
Ethan Zhang operates and maintains Concrete Calc Pilot, an independent collection of free concrete-estimating tools. His responsibilities cover software implementation, published calculation assumptions, repeatable regression testing, source tracking, release checks and correction requests. This is a product and software QA role, not a claim of structural engineering registration or a contractor license.
The calculators cover slab and round-form volumes, multi-section projects, concrete bags, Sonotubes, fence posts, self-leveling products and user-defined slab cost scenarios.
How the calculation QA checks work
Rather than asking visitors to trust an unsupported professional title, the project publishes a dated, seven-tool numerical QA record with sample inputs, the expected values, and links to the actual calculator pages. The automated regression suite checks dimensions and unit conversion, individual versus grouped slab volumes, material allowance applied only once, final whole-bag rounding, embedded fence-post displacement, cost arithmetic, and product-specific self-leveling restrictions.
Example: avoiding a floating-point bag-count error. A 12 × 12 ft slab at 4 in thickness with 10% extra is 52.8 ft³. With a stated 0.60 ft³/80 lb bag, the expected result is 88 bags, not 89. The bag-widget regression test checks this case. Other checks reject invalid measurements, preserve volumes before display rounding, and keep the user-selected material yield separate from the actual geometry.
Example: fence-post subtraction. A filled round hole containing a square embedded post needs concrete for the hole volume minus the space occupied by the post. The QA ledger includes a pooled-versus-per-hole whole-bag rounding example so readers can verify both the method and the purchase-count limitations.
Our manufacturer reference list documents why a bag yield or coverage number was used and where product limitations apply. These are material quantity tools, not project-specific engineering designs or independently certified construction plans.
Engineering advisory input vs. software verification
The project is supported by engineering advisor Enrique García, whose professional background and advisory role are described on a separate public profile. Ethan remains accountable for the website's software, published tests and corrections; advisor credit does not imply that Enrique personally performed the operator's test suite.
No personal LinkedIn profile, GitHub identity, employment history or professional license is listed here without an independently verifiable owner-approved reference. A documented formula and reproducible test are the evidence provided for this software-maintenance role.
Send questions, corrections or new manufacturer data to support@concretecalcpilot.com.