0.00
Outputs
Calculated parameters shown in details card.
Calculated Value
0.00 Outputs
ℹ️ About Ohm's Law Calculator
The Ohm's Law Calculator converts V/I/R/P to Result instantly and accurately. Whether you're sizing electrical equipment, designing circuits, or checking power requirements, this tool gives you fast, reliable results.
📋 How to Use
- Enter the value in V/I/R/P.
- Enter any other required values (voltage, power factor, etc.).
- Click Calculate to convert to Result.
- Read the result and use the formula shown for manual verification.
🔢 Formula / Calculation Method
👥 Who Uses It
- Electricians
- Electronics students
- Engineers
- Hobbyists
- Technicians
📌 Practical Examples
V/I/R/P Input
Enter V/I/R/P value and required parameters.
Result
Instantly see the equivalent Result value.
Circuit Sizing
Use the result to size wires, breakers, or equipment.
Verification
Cross-check manual calculations.
⭐ Benefits
⚡
Fast
Instant conversion results
🎯
Accurate
Industry-standard formulas
📱
Mobile
Works on any device
🔢
Formula
See the math behind results
🌍
Universal
Works for any voltage system
💡 Tips
- 💡Always enter the correct voltage (120V, 220V, 240V, 480V etc.) for your system.
- 💡For 3-phase systems, use the 3-phase formula option if available.
- 💡Power factor is typically 0.8–0.95 — use 0.85 if unsure.
- 💡Always verify calculated values against local electrical codes (NEC, IEC).
❓ Frequently Asked Questions
How do I convert V/I/R/P to Result?
Use the formula: V = I × R | I = V ÷ R | R = V ÷ I | P = V × I
What voltage should I use?
Use your system voltage — 120V or 240V for US residential, 230V for UK/EU.
What is power factor?
Power factor (0–1) represents how efficiently power is used. Use 0.8 as a safe default.
Is the calculator accurate?
Yes, it uses standard electrical engineering formulas.
Is it free?
Yes, completely free.
Should I rely on this for wiring?
Always verify with a licensed electrician before making wiring decisions.
Does it support 3-phase?
Yes, select the 3-phase option if your system uses three-phase power.
What is the difference between kVA and kW?
kW is real power; kVA is apparent power. kW = kVA × Power Factor.
🚀 Features
⚡
Instant Results
Calculate in seconds, no waiting
🎯
High Accuracy
Precise results every time
📱
Mobile Friendly
Works on any device or screen size
🔒
Privacy First
No data stored or shared
🌍
Works Worldwide
Available 24/7 from anywhere
🆓
100% Free
Always free, no registration needed
⚠️ Common Mistakes to Avoid
- ⚠️Using the wrong voltage (120V vs 240V) — this halves or doubles results.
- ⚠️Ignoring power factor for AC circuits — can cause undersized equipment.
- ⚠️Confusing single-phase and three-phase formulas.
- ⚠️Using DC formulas for AC circuits without power factor adjustment.
📖 Glossary
Volt (V)
Unit of electrical potential — the 'pressure' that drives current.
Ampere (A)
Unit of electrical current — the 'flow rate' of electrons.
Watt (W)
Unit of real power — energy per unit time.
kVA
Kilo-Volt-Amperes — unit of apparent power in AC systems.
Power Factor
Ratio of real power to apparent power (0 to 1).
kWh
Kilowatt-hour — unit of energy consumed over time.
📢 Disclaimer
Electrical calculations are provided for reference only. Always consult a licensed electrician and verify against local electrical codes before making wiring or equipment decisions.
About Ohms Law Calculator
Ohm's Law states that current through a conductor between two points is directly proportional to the voltage across the two points. Use this tool to easily calculate any electrical parameter by entering the other two.
📚 Cite & Reference This Calculator
Verified Standard Calculation
Need to cite this calculator for academic papers, engineering notes, or school assignments? Use the reference below:
OnlineConvers. (2026). Ohm's Law Calculator | Voltage, Current, Resistance, Power. Retrieved from https://www.onlineconvers.com/electrical/ohms-law-calculator