Calculation Methodology

All 53 calculators on this site share a single JSON-driven calculation engine. When you enter values, the engine performs the following steps:

1. Input parsing — numeric inputs are validated against min/max/required rules; select inputs are mapped to their numeric values; material selectors pull density from the materials database.
2. SI conversion — every input is automatically converted to its SI base unit (meters, kilograms, seconds, Pascals, Kelvin, Watts). This ensures formulas always operate in a consistent unit system.
3. Formula evaluation — the formula expression is evaluated with mathjs. Formulas are written exactly as they appear in standard engineering references, so they are easy to verify.
4. Output formatting— the result is converted from SI to the display unit specified in the calculator configuration and formatted to the configured precision (decimal places and optional prefix like “k” for thousands).

Every calculator includes at least one test case with known inputs and an expected output taken from a published engineering reference (textbook worked example, standard example problem, or manufacturer data). The engine verifies that computed results match expected values within 0.1% tolerance.

For example, the Pressure Drop Calculator is validated against worked examples in Crane Technical Paper 410, and the Pump Power Calculator against examples in the Cameron Hydraulic Data Book.

Calculators implement formulas from the following primary sources:

• Fluid flow — Darcy-Weisbach equation; Crane TP-410; Moody friction factor (Colebrook-White approximation)
• Pump hydraulics — affinity laws; NPSH per Hydraulic Institute standards
• Heat transfer — LMTD method; Fourier’s law; thermal resistance networks
• Pressure vessels — ASME BPVC Section VIII Div. 1 thin-cylinder formulas (preliminary design only)
• Material properties — ASM International materials data; MatWeb; manufacturer data sheets
• Structural/mechanical — Shigley’s Mechanical Engineering Design; bolt torque per ISO 898-1
• Tank volumes — Standard geometric formulas for cylinders, cones, spheres, ellipsoids

See Data Sources & References for a complete list of standards and references.