Ohm's Law Calculator
Solve voltage, current, resistance and power.
Instant · runs in your browserAbout the Ohm's Law Calculator
Enter any two of voltage (V), current (I), resistance (R) and power (P) and the calculator finds the other two. It is a quick reference for electronics students, technicians and hobbyists.
Formulas
- V = I × R
- P = V × I = I²R = V² ÷ R
Example: 9 V across a 450 Ω resistor gives 20 mA and 0.18 W.
اوہم کا قانون
وولٹیج، کرنٹ، مزاحمت اور طاقت میں سے کوئی دو درج کریں، باقی دو خود معلوم ہو جائیں گی۔ V = I × R۔
- الیکٹرانکس طلباء اور ٹیکنیشنز کے لیے
How to use Ohm's Law Calculator
- Enter your values. Units and defaults are shown beside each field.
- Press Calculate (results also update as you type once calculated).
- Read the result and the step-by-step breakdown with the formula used.
- Copy the result or reset to start again.
Frequently asked questions
How accurate is this calculator?
Calculations use the standard formulas shown on the page, computed in full precision and rounded only for display. The result is only as accurate as the inputs and assumptions listed.
Can I use this for engineering design?
No. These are rough quantity estimates using the assumptions shown (wastage, densities, mix ratios). Get structural and electrical work designed and approved by a qualified engineer.
Is it free?
Yes. All tools are free to use without an account.