Methodology

VoltCalc is a collection of small, focused electrical calculators. This page explains how they work so you can judge the results for yourself.

Everything runs in your browser

Every calculation happens locally on your device using JavaScript. The values you enter are never sent to a server and are not stored by us. Optional result history is kept only in your own browser's local storage.

Transparent formulas

Each calculator shows the exact formula it uses, right on the page, along with the symbols and units involved. We prefer standard, textbook formulas (Ohm's law, P = √3 × V_L × I × PF, voltage drop, RC cut-off and so on) rather than hidden "black box" logic.

Reference data and standards

Where a tool relies on tabulated data, we use widely recognised sources and state the basis on the tool page:

• Wire ampacity: NEC Table 310.16 (AWG) and IEC 60364-5-52 reference method C (mm²).
• Conduit fill: NEC Chapter 9 fill percentages (53/31/40%).
• Motor and transformer sizing: NEC Article 430 and standard kVA / full-load-current relationships.

These tables are simplified to a single common case (for example one circuit at 30 °C ambient). Real installations may need derating for temperature, grouping or installation method.

Rounding and standard sizes

Results are rounded for readability, and "suggested" sizes are chosen from standard ranges (AWG/kcmil, mm², standard fuse and breaker ratings). Intermediate maths is done at full precision.

Estimates, not designs

These tools give fast estimates for learning and planning. They do not replace a full design or your local electrical code — please also read our disclaimer.