Use of the calculators
You can use all 21 calculators free of charge for personal, educational and commercial work, such as quoting a job, checking homework or sizing equipment. Do not disrupt the service, scrape it at a scale that slows it down or use it for anything unlawful.
What the results assume
The results rest on 7 assumptions: three-phase loads are balanced; voltage and current are RMS values; the supply sits at its nominal voltage; battery runtime equals Ah ÷ A with no depth-of-discharge or high-current losses; generator ratings use power factor 0.8; EV charging runs at constant power with the efficiency you enter; and breaker, MCB and generator suggestions add a 25% margin to the load. Real equipment differs from these conditions.
Not professional advice
Breaker, MCB, cable and generator suggestions are starting points for planning, not designs. Follow your local electrical code, such as the NEC, BS 7671, AS/NZS 3000 or IEC 60364, and have a licensed electrician check ratings and protection before installing or switching on anything.
No warranty
The website and calculators are provided "as is" and "as available", without warranties of any kind, express or implied, including accuracy, fitness for a particular purpose or uninterrupted availability.
Limitation of liability
To the fullest extent permitted by law, AmpToKW and its operator are not liable for any direct, indirect, incidental or consequential loss or damage arising from the use of, or reliance on, the website or its results, including damage to equipment, property or persons.
Intellectual property
The design, text, code and graphics of AmpToKW are protected by copyright. You can share links, quote results and copy formulas and chart values into your own notes, reports and spreadsheets. Do not copy or republish the site or its pages as a whole without permission.
Changes and contact
We update these terms when the site changes; the date at the top shows the current version. These terms are governed by the laws of the country where the site operator is established. Send questions about these terms to the email address below.