About Arch Calculator
Arch Calculator was created to bridge the gap between pure architectural geometry and real-world jobsite execution.
Our Core Mission
Eliminate costly layout mistakes, bowed trim, and unstable masonry arches by providing finish carpenters, drywall installers, bricklayers, and architects with instant, mathematically verified layout coordinates, fractional dimensions, and voussoir calculations.
Mathematical Rigor & Engineering Models
Unlike generic chord calculators, Arch Calculator models seven distinct geometric arch classifications:
- Segmental Arches: Computed via the Intersecting Chords Theorem with continuous sagitta curves.
- Elliptical Arches: Scribed using true semi-major and semi-minor focal point distances (c = √(a² - b²)) and Ramanujan perimeter approximations.
- Gothic & Pointed Arches: Dual-arc equilateral and lancet intersections.
- Masonry Voussoirs: Strict adherence to odd-integer brick count laws ensuring a central apex keystone and calculated skewback seating angles.
Editorial & Trade Standards
Every equation, guide, and layout method published on this website is peer-reviewed by seasoned construction drafters, finish carpenters, and structural engineering guidelines. We do not provide generic approximations; we provide field-ready coordinates down to 1/16" carpenter fractions.