Electronics Calculator

Ohm's Law Calculator

Calculate Voltage (V), Current (I) or Resistance (R) instantly using Ohm's Law. Enter any two values and the calculator automatically computes the third.

Calculator

How to Use

  1. Enter any two values.
  2. Leave the unknown field empty.
  3. Click Calculate.
  4. The missing value is calculated automatically.

Ohm's Law Formula

Unknown Formula
Current I = V ÷ R
Voltage V = I × R
Resistance R = V ÷ I

Example

Voltage = 24 V

Resistance = 8 Ω

Current:

24 ÷ 8 = 3 A

JavaScript 


function calculateOhmsLaw(){

    let V=parseFloat(document.getElementById('voltage').value);
    let I=parseFloat(document.getElementById('current').value);
    let R=parseFloat(document.getElementById('resistance').value);

    let filled=0;

    if(!isNaN(V)) filled++;
    if(!isNaN(I)) filled++;
    if(!isNaN(R)) filled++;

    if(filled!=2){

        document.getElementById('result').innerHTML=
        'Please enter exactly two values.';

        return;

    }

    let html='';

    if(isNaN(V)){

        V=I*R;
        html='
Voltage
'+V.toFixed(3)+' V
';

    }else if(isNaN(I)){

        I=V/R;
        html='
Current
'+I.toFixed(3)+' A
';

    }else{

        R=V/I;
        html='
Resistance
'+R.toFixed(3)+' Ω
';

    }

    document.getElementById('result').innerHTML=html;

}

function clearResult(){

    document.getElementById('result').innerHTML='';

}

Features

  • Calculate Voltage.
  • Calculate Current.
  • Calculate Resistance.
  • Instant calculation.
  • Works on desktop and mobile.
  • No page reload.