Online Power Calculator

This free Online Power Calculator lets you calculate Online Power without installing anything. Use the tool below and see your result straight away.

How to use the Online Power Calculator

Enter a value for “Voltage (V)”.
Enter a value for “Current (I)”.
Click “Calculate Power”.
Your result shows on the page.

Why use this Online Power Calculator?

The Online Power Calculator is handy for school, work and everyday decisions. It is free, easy to use and works on any device.

Skip manual maths and avoid simple mistakes
Get a result as soon as you enter your numbers
Try different values as often as you like

Online Power Calculator – frequently asked questions

Is the Online Power Calculator free to use?

Yes, it is free. You can use the Online Power Calculator as often as you like without signing up.

Do I need to install anything?

No. It runs in your web browser on a phone, tablet or computer.

Is my data safe when I use the Online Power Calculator?

The tool runs in your browser, so what you enter is processed on your own device and is not sent to our servers.

How accurate is the Online Power Calculator?

It follows standard formulas and shows the result on the page. For important choices, such as money, health or exams, please double-check the result with an official source or a professional.

More free Calculators

Browse all Calculators on Ilmhunt, or see all free online tools.

Embed this tool on your website — free

Copy the code below to add this working tool to your own page. A small credit link stays with it — that’s all we ask.

<iframe srcdoc="&lt;!DOCTYPE html&gt;
&lt;html lang=&quot;en&quot;&gt;
&lt;head&gt;
  &lt;meta charset=&quot;UTF-8&quot;&gt;
  &lt;meta name=&quot;viewport&quot; content=&quot;width=device-width, initial-scale=1.0&quot;&gt;
  &lt;title&gt;Power Calculator&lt;/title&gt;
  &lt;script src=&quot;https://cdn.jsdelivr.net/npm/chart.js&quot;&gt;&lt;/script&gt;
  &lt;style&gt;
    body { font-family: Arial, sans-serif; text-align: center; margin-top: 50px; }
    input { padding: 10px; margin: 10px; width: 80%; font-size: 16px; }
    button { padding: 10px 20px; font-size: 18px; cursor: pointer; }
    canvas { width: 80%; height: 300px; margin-top: 20px; }
    #result { font-size: 20px; color: #333; margin-top: 20px; }
  &lt;/style&gt;
&lt;/head&gt;
&lt;body&gt;
  &lt;h1&gt;Power Calculator (P = V * I)&lt;/h1&gt;
  
  &lt;label for=&quot;voltage&quot;&gt;Voltage (V): &lt;/label&gt;
  &lt;input type=&quot;number&quot; id=&quot;voltage&quot; placeholder=&quot;Enter Voltage (V)&quot;&gt;
  
  &lt;label for=&quot;current&quot;&gt;Current (I): &lt;/label&gt;
  &lt;input type=&quot;number&quot; id=&quot;current&quot; placeholder=&quot;Enter Current (I)&quot;&gt;
  
  &lt;button onclick=&quot;calculatePower()&quot;&gt;Calculate Power&lt;/button&gt;
  
  &lt;div id=&quot;result&quot;&gt;&lt;/div&gt;
  
  &lt;h2&gt;Power vs Voltage/Current&lt;/h2&gt;
  &lt;canvas id=&quot;powerGraph&quot;&gt;&lt;/canvas&gt;
  
  &lt;script&gt;
    function calculatePower() {
      const voltage = parseFloat(document.getElementById('voltage').value);
      const current = parseFloat(document.getElementById('current').value);
      
      if (isNaN(voltage) || isNaN(current)) {
        document.getElementById('result').innerHTML = &quot;Please enter both Voltage and Current.&quot;;
        return;
      }

      const power = voltage * current;
      
      // Show the result in text
      document.getElementById('result').innerHTML = `Power (P) = ${power.toFixed(2)} Watts`;
      
      // Graph the power
      const ctx = document.getElementById('powerGraph').getContext('2d');
      new Chart(ctx, {
        type: 'bar',
        data: {
          labels: ['Voltage (V)', 'Current (I)'],
          datasets: [{
            label: 'Power (P = V * I)',
            data: [voltage * current, voltage * current],
            backgroundColor: ['rgba(75, 192, 192, 0.2)', 'rgba(75, 192, 192, 0.2)'],
            borderColor: ['rgba(75, 192, 192, 1)', 'rgba(75, 192, 192, 1)'],
            borderWidth: 1
          }]
        },
        options: {
          scales: {
            y: { beginAtZero: true }
          }
        }
      });
    }
  &lt;/script&gt;
&lt;style&gt;html,body{height:auto!important;min-height:0!important;max-height:none!important}&lt;/style&gt;&lt;script&gt;(function(){function wpcPost(){try{parent.postMessage({wpcId:112,wpcH:document.body.scrollHeight},'*');}catch(e){}}window.addEventListener('load',wpcPost);try{new MutationObserver(wpcPost).observe(document.body,{childList:true,subtree:true,attributes:true});}catch(e){}window.addEventListener('resize',wpcPost);setInterval(wpcPost,600);})();&lt;/script&gt;&lt;/body&gt;
&lt;/html&gt;
" id="wpc-frame-112" class="wpc-embed-frame" style="width:100%;border:0;display:block;overflow:hidden;" scrolling="no"></iframe>
<p><a href="https://ilmhunt.com/online-power-calculator/" target="_blank" rel="noopener">Online Power Calculator</a> by <a href="https://ilmhunt.com/" target="_blank" rel="noopener">IlmHunt</a> — free online tools</p>