<!doctypehtml><meta charset=utf-8><meta content=width=device-width,initial-scale=1.0 name=viewport><meta content="text/html; charset=utf-8"http-equiv=Content-Type><meta content='(PICS-1.1 "http://www.classify.org/safesurf/" L gen true for "http://www.onlineconversion.com/" r (SS~~000 1))'http-equiv=PICS-Label><title>
   Online Conversion - Ohm's Law Calculator
  </title><meta content="Calculators for Ohms Law. Calculate voltage, current, resistance, and power. Convert watts, volts, and amps."name=DESCRIPTION><meta content="current, amps, ampere, voltage, volts, power, watts, wattage, resistance, ohms"name=KEYWORDS><link href=/assets/style.css rel=stylesheet><script src=/assets/misc_functions.js></script><body><div class=container><div class=header_area><div class=header><div class=logo><img alt="Online Conversion"title="Online Conversion"height=53 src=/assets/rf_logo.gif width=142></div></div></div><div class=mainmenu_area><div class=mainmenu><div class=nav><ul><li><a href=/> Home </a><li><a href=/faq.htm> FAQ </a><li><a href=http://forum.onlineconversion.com/> Message Forum </a><li><a href=/contact.htm> Contact Us </a></ul></div></div></div><div class=main_content><div class=content_left><div class=content_heading><h2>Welcome to OnlineConversion.com</h2><p class=red>Ohm's Law Calculator</p><script language=JavaScript src=/assets/browser_detection.js></script><noscript><blockquote><p><font color=#FF0000 size=3> <b> You do not have JavaScript enabled. </b> </font> <br> <font color=#000080 size=2> The conversions on this site require the use of JavaScript so please enable before continuing. For assistance in enabling JavaScript, please contact the webmaster. </font></blockquote></noscript></div><script language=JavaScript><!--
// Copyright 2004 by Robert Fogt and OnlineConversion.com
// No use without permission

function stripBad(string) {
    for (var i=0, output='', valid="eE-0123456789."; i<string.length; i++)
       if (valid.indexOf(string.charAt(i)) != -1)
          output += string.charAt(i)
    return output;
} 

function calculate() {
  var lvolts, lamps, lwatts, lohms;
  var mvolts, mamps, mwatts, mohms;

  with (document.ohmslaw) {
     lvolts = stripBad(volts.value);
     volts.value = lvolts;
     lamps = stripBad(amps.value);
     amps.value = lamps;
     lwatts = stripBad(watts.value);
     watts.value = lwatts;
     lohms = stripBad(ohms.value);
     ohms.value = lohms;

    for (i = 0; i < 4; i++){
       if (rb_volts[i].checked) mvolts = parseFloat(rb_volts[i].value);
       if (rb_amps[i].checked) mamps = parseFloat(rb_amps[i].value);
       if (rb_ohms[i].checked) mohms = parseFloat(rb_ohms[i].value);
       if (rb_watts[i].checked) mwatts = parseFloat(rb_watts[i].value);
     }
  }

  var valueCount = 0;
  if (lvolts == "") valueCount++;
  if (lamps == "") valueCount++;
  if (lwatts == "") valueCount++;
  if (lohms == "") valueCount++;

  if (valueCount < 2) {
    alert("You must enter exactly 2 values. The remaining 2 values will be calculated.\n\nIf you do not know 2 of the values, you will not be able to calculate the others.");
     return;
  }
  if (valueCount > 2) {
    alert("You must enter exactly 2 values. Entering more than 2 values will not work.");
     return;
  }

  if ((lvolts != "") & (lamps != "")){
    lvolts = parseFloat(lvolts) * mvolts;
    lamps = parseFloat(lamps) * mamps;
     lwatts = lvolts * lamps;
     lohms = lvolts / lamps;
  }
  else if ((lvolts != "") & (lohms != "")){
    lvolts = parseFloat(lvolts) * mvolts;
    lohms = parseFloat(lohms) * mohms;
     lwatts = (lvolts * lvolts) / lohms;
     lamps = (lvolts / lohms);
  }
  else if ((lvolts != "") & (lwatts != "")){
    lvolts = parseFloat(lvolts) * mvolts;
    lwatts = parseFloat(lwatts) * mwatts;
     lamps = lwatts / lvolts;
     lohms = (lvolts * lvolts) / lwatts;
  }
  else if ((lamps != "") & (lohms != "")){
    lamps = parseFloat(lamps) * mamps;
    lohms = parseFloat(lohms) * mohms;
     lvolts = lamps * lohms;
     lwatts = (lamps * lamps) * lohms;
  }
  else if ((lamps != "") & (lwatts != "")){
    lamps = parseFloat(lamps) * mamps;
    lwatts = parseFloat(lwatts) * mwatts;
     lvolts = lwatts / lamps;
     lohms = lwatts / (lamps * lamps);
  }
  else if ((lohms != "") & (lwatts != "")){
    lohms = parseFloat(lohms) * mohms;
    lwatts = parseFloat(lwatts) * mwatts;
     lvolts = Math.sqrt(lwatts * lohms);
     lamps = Math.sqrt(lwatts / lohms);
  }

     with (document.ohmslaw){
       volts.value = lvolts / mvolts;
       amps.value = lamps / mamps;
       watts.value = lwatts / mwatts;
       ohms.value = lohms / mohms;
     }

}

//--></script><p>Enter any 2 values then click "Calculate". The unknown values will be calculated.<form name=ohmslaw><center> <table border=0><tbody><tr><td>Voltage<td><input name=volts size=10><td bgcolor=#C6D1FF><input name=rb_volts type=radio value=0.001> <font size=-1> millivolts </font><td bgcolor=#C6D1FF><input checked name=rb_volts type=radio value=1> <font size=-1> volts </font><td bgcolor=#C6D1FF><input name=rb_volts type=radio value=1000> <font size=-1> kilovolts </font><td bgcolor=#C6D1FF><input name=rb_volts type=radio value=1000000> <font size=-1> megavolts </font><tr><td>Current<td><input name=amps size=10><td bgcolor=#C6D1FF><input name=rb_amps type=radio value=0.001> <font size=-1> milliamps </font><td bgcolor=#C6D1FF><input checked name=rb_amps type=radio value=1> <font size=-1> amps </font><td bgcolor=#C6D1FF><input name=rb_amps type=radio value=1000> <font size=-1> kiloamps </font><td bgcolor=#C6D1FF><input name=rb_amps type=radio value=1000000> <font size=-1> megaamps </font><tr><td>Resistance<td><input name=ohms size=10><td bgcolor=#C6D1FF><input name=rb_ohms type=radio value=0.001> <font size=-1> milliohms </font><td bgcolor=#C6D1FF><input checked name=rb_ohms type=radio value=1> <font size=-1> ohms </font><td bgcolor=#C6D1FF><input name=rb_ohms type=radio value=1000> <font size=-1> kilohms </font><td bgcolor=#C6D1FF><input name=rb_ohms type=radio value=1000000> <font size=-1> megaohms </font><tr><td>Power<td><input name=watts size=10><td bgcolor=#C6D1FF><input name=rb_watts type=radio value=0.001> <font size=-1> milliwatts </font><td bgcolor=#C6D1FF><input checked name=rb_watts type=radio value=1> <font size=-1> watts </font><td bgcolor=#C6D1FF><input name=rb_watts type=radio value=1000> <font size=-1> kilowatts </font><td bgcolor=#C6D1FF><input name=rb_watts type=radio value=1000000> <font size=-1> megawatts </font><tr><td align=center colspan=5><input onclick=javascript:calculate(); type=button value=Calculate>   <input type=reset value=Clear></table> </center></form><p>Ohm's Law defines the relationship between power, voltage, current, and resistance. The various possible formulas for Ohm's law are as follows.<p>Where <br> P = power in watts <br> E = voltage in volts <br> I = current in amps <br> R = resistance in ohms<p>P = E <sup> 2 </sup> /R <br> P = I <sup> 2 </sup> * R <br> P = E * I<p>E = sqrt(P * R) <br> E = P/I <br> E = I * R<p>I = E/R <br> I = P/E <br> I = sqrt(P/R)<p>R = E/I <br> R = E <sup> 2 </sup> /P <br> R = P/I <sup> 2 </sup></div><div class=content_right><div class=bookmark><h3>BookMark Us</h3><p>It may come in handy.</div><div class=quick_link><script><!--
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