Kilowatt-Hour (kWh) Calculator
Calculate energy consumption and electricity costs accurately
kWh Energy Calculator
IEEE 1459 Standard Compliant
Results:
Energy Consumed: 0.00 kWh
Power Used: 0.00 kW
Electricity Cost: $0.00
Daily Cost: $0.00
Monthly Cost: $0.00
Annual Cost: $0.00
How to Use the kWh Calculator
Power & Time Method
- Select "Power & Time" calculation method
- Enter the power consumption in kilowatts (kW)
- Input the operating time in hours
- Enter your electricity rate per kWh
- Click "Calculate" to get energy consumption and costs
Best for: Appliances with known power ratings
Electrical Parameters Method
- Select "Electrical Parameters" method
- Choose AC or DC system type
- For AC: Select single or three-phase
- Enter voltage, current, and power factor
- Input operating time and electricity rate
- Calculate to get comprehensive results
Best for: When you have electrical measurements
Understanding Results
- Energy Consumed: Total kWh used
- Power Used: Average power consumption
- Electricity Cost: Cost for the specified period
- Daily/Monthly/Annual: Projected costs if usage continues
Note: Projections assume constant usage patterns
How to Calculate kWh
Basic Formula
kWh = Power (kW) × Time (hours)
This is the fundamental equation for energy consumption. Kilowatt-hours represent the amount of energy used when 1 kilowatt of power is consumed for 1 hour.
From Electrical Parameters
Single Phase AC: kWh = (V × I × PF × t) / 1000
Three Phase AC: kWh = (√3 × V × I × PF × t) / 1000
DC Systems: kWh = (V × I × t) / 1000
Where: V = Voltage, I = Current, PF = Power Factor, t = Time
Detailed Calculation Example
Example 1: Air Conditioner (Power & Time Method)
• Power Rating: 3.5 kW
• Operating Time: 8 hours/day
• Electricity Rate: $0.12/kWh
Calculation:
kWh = 3.5 kW × 8 hours = 28 kWh
Daily Cost = 28 kWh × $0.12 = $3.36
Monthly Cost = $3.36 × 30 = $100.80
Annual Cost = $3.36 × 365 = $1,226.40
Example 2: Electric Heater (Electrical Parameters)
• System: Single Phase AC
• Voltage: 240V
• Current: 20A
• Power Factor: 1.0 (resistive load)
• Time: 6 hours
Calculation:
Power = 240V × 20A × 1.0 = 4,800W = 4.8 kW
kWh = 4.8 kW × 6 hours = 28.8 kWh
Cost = 28.8 kWh × $0.12 = $3.46
kWh Calculation Formulas
Basic Energy Formula:
kWh = Power (kW) × Time (hours)
AC Single Phase:
kWh = (V × I × PF × t) / 1000
AC Three Phase:
kWh = (√3 × V × I × PF × t) / 1000
DC Systems:
kWh = (V × I × t) / 1000
Cost Calculation:
Cost = kWh × Rate ($/kWh)
Common Conversions
- 1,000 Wh (watt-hours)
- 3.6 MJ (megajoules)
- 3,412 BTU
- 860 kcal (kilocalories)
- 1 day = 24 hours
- 1 month ≈ 30 days
- 1 year = 365 days
- 1 year = 8,760 hours