Ohm's Law Calculator 2026 | Voltage Current Resistance Solver

Ohm's Law Calculator — Voltage, Current, Resistance & Power

Ohm's Law is the fundamental relationship governing electrical circuits: Voltage equals Current multiplied by Resistance (V = I × R). This calculator solves for any of the three values given the other two, plus calculates power dissipation.

The Four Key Formulas

Voltage: V = I × R
Current: I = V ÷ R
Resistance: R = V ÷ I
Power: P = V × I

Practical Applications

Ohm's Law calculations are essential for selecting correct resistor values in circuits, sizing power supplies, calculating fuse/breaker ratings, and troubleshooting electrical faults — used by electronics hobbyists, students, and professional engineers alike.

Frequently Asked Questions

Does Ohm's Law apply to all electrical components? +

Ohm's Law applies precisely to 'ohmic' components like standard resistors, where resistance stays constant regardless of voltage/current. Non-ohmic components (diodes, transistors, light bulbs at high temperature) have variable resistance and don't follow a simple linear V=IR relationship.

Why is power dissipation important to check? +

Components have maximum power ratings. If actual power dissipation (calculated as P=VI) exceeds a resistor's rated wattage, it will overheat and potentially fail or cause a fire hazard — always verify components are rated for the calculated power.

What's the difference between AC and DC for this calculator? +

This calculator assumes simple DC (direct current) relationships. AC (alternating current) circuits involve additional factors like impedance, frequency, and phase angle, which require more complex calculations beyond basic Ohm's Law.

🔄 Last Updated: September 2026 · Rule year is shown where relevant; verify source-linked rules before filing or payment

Ohm's Law Formulas

V = I × R (Voltage = Current × Resistance)
I = V ÷ R (Current = Voltage ÷ Resistance)
R = V ÷ I (Resistance = Voltage ÷ Current)
P = V × I (Power = Voltage × Current)

Worked Example

A 100W bulb on 230V mains. Current = 100 ÷ 230 = 0.43A. Resistance = 230 ÷ 0.43 = 535 Ω. Monthly energy at 8 hrs/day = 100W × 8h × 30 = 24 kWh. At ₹8/unit = ₹192/month per bulb. An LED equivalent (10W) costs only ₹19.2/month.

Tips

Higher resistance = lower current = less power consumption
India uses 230V AC at 50Hz — different from US (120V, 60Hz)
Always check device voltage ratings before connecting to Indian power supply

Ohm's Law Calculator — Electricity Basics for Indian Homes and Engineering

Ohm's Law is the fundamental principle governing electricity — it describes the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit. Formulated by German physicist Georg Ohm in 1827, it is expressed as V = I × R. Understanding Ohm's Law is essential for anyone dealing with electrical systems, from home wiring to electronics to industrial applications.

The Three Forms of Ohm's Law: V = I × R (Voltage = Current × Resistance). I = V ÷ R (Current = Voltage ÷ Resistance). R = V ÷ I (Resistance = Voltage ÷ Current). The fourth relationship for power: P = V × I (Power in Watts = Voltage × Current). These four equations form the complete set for basic circuit analysis. If you know any two values, you can calculate the other two.

Practical Application — Understanding Your Home Electricity Bill: India's standard household supply is 230V AC at 50Hz. A 100W LED bulb: Current = P ÷ V = 100 ÷ 230 = 0.43A. Resistance = V ÷ I = 230 ÷ 0.43 = 535 Ω. Running 8 hours/day for 30 days: 100W × 8 × 30 = 24 kWh = 24 units. At ₹8/unit = ₹192/month per bulb. Replacing with a 10W LED: ₹19.20/month — saving ₹172.80/month per bulb.

MCB (Miniature Circuit Breaker) Ratings and Ohm's Law: MCBs protect circuits by tripping when current exceeds their rating. A 6A MCB on a lighting circuit protects against more than 6A of current draw. Total power at 230V with 6A limit = 230 × 6 = 1,380W maximum load. Never connect appliances exceeding this limit on a single circuit — it causes MCB tripping and potential wire overheating if the MCB is faulty.

Series and Parallel Circuits in Indian Home Wiring: Indian homes use parallel circuits — each electrical outlet and light point connects directly between live and neutral. This ensures all appliances receive the full 230V regardless of others. In series, current is the same through all components but voltage is shared — used in some types of Christmas lights and not in power distribution. Understanding parallel circuits explains why all your appliances work at rated voltage simultaneously, and why turning off one doesn't affect others.

CalcuTools India · Free calculator · Updated September 2026 · Applicable rule year shown on this page · Verify engineering designs and safety requirements with the applicable standards · About · How we verify

About the Ohms Law

This free Indian calculator helps you compute an estimate for ohms law — reviewed for the applicable current period. Calculations use documented formulas and source notes shown on this page where applicable.

How to Use This Calculator

Enter your values in the fields above and click Calculate. Results update instantly. You can adjust any input and recalculate as many times as needed — completely free with no sign-up required.

Accuracy and Verification

Our ohms law formulas are sourced from official Indian regulatory bodies including the Income Tax Department, EPFO, RBI, Ministry of Finance, and WHO where applicable. We verify results against official calculators before publishing and update with every budget and policy change.

Disclaimer

Results are estimates based on the inputs you provide. Actual outcomes can vary with the rules, rates, prices, biological conditions, or other assumptions that apply to your situation. Review the assumptions and effective date shown on this page before using a result for an important decision.

CalcuTools India · Free calculator platform · About us · How we verify · Last Updated September 2026 · Applicable rule year shown on this page

⚡ Ohm's Law Calculator