Free
Voltage Drop Calculator
VD = k × I × L × (R cos φ + X sin φ)
Single-phase, three-phase and DC voltage drop in sq mm or AWG under 15 national codes (IEC, NEC, BS 7671, SP 30 and more), with your own cable data if you have it.
03 · Calculations
Engineering Calculators & Formulas
Free calculators that show their working: the formula, the inputs, a step-by-step method and a worked example, so you can check the answer, not just get one.
All calculators
Each one shows the formula, a step-by-step method and a worked example.
Explore other sections
- 01 Technology Clear explainers on the devices, networks and standards you use every day, from Wi-Fi and USB-C to smart homes and batteries.
- 02 Engineering Engineering for people who design, install and maintain real systems: electrical installations, power, energy, EV charging and safety.
- 04 How-To Step-by-step guides for practical jobs at home and at work, written with safety and real-world limits in mind.
- 05 Apps & Software Guides to the software worth your time: engineering tools, spreadsheets, automation and the habits that make digital work reliable.
- 06 World Global developments in technology, energy and industry, explained calmly: what happened, why it matters and what changes next.
- 07 AI AI without the hype: how it works, where it helps, where it fails and how to use it responsibly in technical work.
- 08 Shop Handbooks, apps, calculators and digital tools from EngiLoop.