Enter Load Details
Formula Used
Direct current: kW = Amps × Volts ÷ 1000
Single phase AC: kW = Amps × Volts × Power Factor ÷ 1000
Three phase AC: kW = √3 × Amps × Volts × Power Factor ÷ 1000
Energy: kWh = kW × Hours
Cost: Cost = kWh × Price per kWh
How To Use This Calculator
- Enter the current in amps from the label or meter.
- Enter the voltage for the circuit or equipment.
- Select direct current, single phase, or three phase.
- Add a power factor for alternating current loads.
- Enter run time, quantity, efficiency, margin, and price.
- Press calculate to see kW, kWh, cost, and design values.
Example Data Table
| Load Type | Amps | Volts | Power Factor | Hours | Approx kW | Approx kWh |
|---|---|---|---|---|---|---|
| Direct current tool | 20 | 24 | Not used | 3 | 0.48 | 1.44 |
| Single phase appliance | 12 | 120 | 0.90 | 5 | 1.296 | 6.48 |
| Three phase motor | 15 | 400 | 0.85 | 2 | 8.833 | 17.666 |
Understanding Amps To kW Per Hour
Amps measure electrical current. Kilowatts measure real power. Kilowatt-hours measure energy used over time. This calculator connects those values in one clear workflow. It is useful for motors, heaters, chargers, pumps, shop tools, and three phase equipment.
Why The Unit Matters
Many people say kW per hour. In daily use, they usually mean kWh for one hour. A kilowatt is already a rate of power. A kilowatt-hour is the energy used when that power runs for a chosen time. For example, a 2 kW load running for one hour uses 2 kWh. The same load running for four hours uses 8 kWh.
Power Factors And Phase Types
Direct current uses amps and volts only. Single phase alternating current also uses power factor. Three phase systems use the square root of three because the line currents are separated by phase angle. Power factor is important for motors, transformers, compressors, and inductive loads. A low power factor means more current is needed for the same useful power.
Advanced Load Planning
Real systems have losses. The efficiency field estimates useful output from the electrical input. A motor, inverter, or power supply may waste heat during operation. The quantity field lets you total several equal devices. The safety margin field supports design checks. It can help size circuits, backup power, or operating reserves.
Energy And Cost Use
Once kilowatts are known, time changes power into energy. Multiply kilowatts by hours to get kWh. Then multiply kWh by the energy price to estimate cost. This makes the tool useful for daily use, job costing, battery planning, generator sizing, and comparing equipment options.
Better Input Decisions
Use nameplate voltage when it matches the circuit. Use measured voltage when accuracy matters. For three phase systems, enter line to line voltage. Use a realistic power factor for alternating current loads. Resistive heaters often sit near 1.00. Motors may range lower, especially when lightly loaded. Use rated current for planning. Use measured current for testing.
Practical Safety Notes
This tool gives planning values. It does not replace electrical codes, site inspection, or professional design. Conductors, breakers, temperature, duty cycle, voltage drop, starting current, and local rules still matter. High starting loads can exceed running power for a short time. Always leave room for real world variation. Check equipment labels before relying on any estimate.
Final Value
The main result shows adjusted kW and kWh. The one hour energy value equals the adjusted kW for a one hour run. That number helps users understand the phrase kW per hour. It also makes monthly estimates easy. Multiply the result by daily hours and days of use.
Record each assumption with the result. Small changes in voltage, power factor, or run time can alter totals. Keeping notes makes repeat estimates easier. It also helps teams compare several electrical choices fairly during later reviews and future upgrades.
FAQs
What does amps to kW per hour mean?
It usually means converting current into kilowatts, then finding kilowatt-hours for one hour or another run time. kW is power. kWh is energy used over time.
Is kW per hour the same as kWh?
No. kW is a power rate. kWh is energy. Many users say kW per hour when they want the energy used by a load during one hour.
What formula is used for direct current?
For direct current, multiply amps by volts. Then divide by 1000. Power factor is not used for direct current in this calculator.
What formula is used for single phase AC?
For single phase AC, multiply amps by volts and power factor. Then divide by 1000. This gives real power in kilowatts.
What formula is used for three phase AC?
For three phase AC, multiply square root of three by amps, volts, and power factor. Then divide by 1000. Use line to line voltage.
What power factor should I enter?
Use the value from the equipment label when available. Use 1.00 for mostly resistive heaters. Motors and inductive loads often use lower values.
Why does the calculator include hours?
Hours convert power into energy. A load using 3 kW for 2 hours consumes 6 kWh. Billing and battery estimates usually need kWh.
How does efficiency affect the result?
Efficiency estimates useful output power from electrical input power. It does not increase billed energy. It helps compare losses in motors, inverters, and supplies.
Why add a safety margin?
A safety margin helps planning. It allows room for variation, heat, voltage changes, and design reserve. It should not replace electrical code checks.
Can I estimate electricity cost?
Yes. Enter your price per kWh. The calculator multiplies energy use by that rate. The result is an estimate for the chosen run time.
Can this size a breaker or cable?
No. It gives planning values only. Breaker and cable sizing also need code rules, duty cycle, temperature, voltage drop, and starting current.