⚡ Quick Answer
Electricity cost = Power (kW) x Time (hours) x Rate (per kWh). Example: a 1,500W air conditioner running 8 hours per day at 30 rupees/kWh costs: 1.5kW x 8h x 30 = 360 rupees per day = 10,800 rupees per month. Understanding appliance costs helps identify where to save on your electricity bill!
📂 Daily Life

⚡ Electricity Cost Calculator

Calculate the electricity cost of any appliance. Find out which devices use the most power and how much they cost per day, month, and year. Identify where to save on your bill!

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🦉Owl's Explanation
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✅ Trusted Tool
The 365tool.net Electricity Cost Calculator uses standard electrical power calculation. Enter your actual rate from your electricity bill for most accurate results. Free for homeowners and businesses everywhere. No sign-up needed.

🤔 How Does This Work?

The Electricity Cost Calculator uses a simple formula:

Cost = (Watts / 1000) x Hours x Rate per kWh

  • Convert watts to kilowatts (divide by 1,000)
  • Multiply by daily usage hours to get daily kWh
  • Multiply by electricity rate to get daily cost
  • Extrapolate to monthly and annual costs

❓ Frequently Asked Questions

What is a kWh (kilowatt-hour)?
kWh is the standard unit for measuring electricity consumption. 1 kWh = 1,000 watts running for 1 hour. A 100W bulb running for 10 hours uses 1 kWh. A 1,000W heater running for 1 hour uses 1 kWh. Electricity bills are charged per kWh. In Sri Lanka, residential electricity rates range from about 7-70 rupees per kWh depending on usage band.
Which appliances use the most electricity?
High consumers: air conditioner (1,000-3,000W), electric water heater (2,000-4,000W), electric oven (2,000-5,000W), clothes dryer (2,500-5,000W), refrigerator (150-400W but runs 24/7). Medium: washing machine (500-1,500W per cycle), computer (100-500W). Low: LED bulbs (5-15W), phone charger (5-20W).
How can I reduce electricity bills?
Switch to LED bulbs (use 80% less than incandescent). Use air conditioner efficiently: set to 24-26°C, clean filters monthly. Unplug devices on standby (phantom loads add 5-10%). Wash clothes in cold water. Run dishwasher and laundry at night (lower rates). Install solar panels for long-term savings.
What is the electricity rate in Sri Lanka?
Sri Lanka uses tiered pricing (more you use, higher rate per unit). Residential: 0-30 units: ~7.85/kWh. 31-60: ~10/kWh. 61-90: ~27.75/kWh. 91-120: ~32/kWh. Above 120: ~45-72/kWh. Industrial and commercial rates differ. Rates change periodically — check your latest bill for current rates.
Can solar panels eliminate my electricity bill?
Potentially yes. A properly sized solar system can offset most or all consumption. Net metering allows you to sell excess power back to the grid. In Sri Lanka, a 1kW solar system costs about 200,000-300,000 rupees and generates about 100-130 kWh per month. Payback period is typically 5-8 years.
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❓ FAQ
What is a kWh (kilowatt-hour)?
kWh is the standard unit for measuring electricity consumption. 1 kWh = 1,000 watts running for 1 hour. A 100W bulb running for 10 hours uses 1 kWh. A 1,000W heater running for 1 hour uses 1 kWh. Electricity bills are charged per kWh. In Sri Lanka, residential electricity rates range from about 7-70 rupees per kWh depending on usage band.
Which appliances use the most electricity?
High consumers: air conditioner (1,000-3,000W), electric water heater (2,000-4,000W), electric oven (2,000-5,000W), clothes dryer (2,500-5,000W), refrigerator (150-400W but runs 24/7). Medium: washing machine (500-1,500W per cycle), computer (100-500W). Low: LED bulbs (5-15W), phone charger (5-20W).
How can I reduce electricity bills?
Switch to LED bulbs (use 80% less than incandescent). Use air conditioner efficiently: set to 24-26°C, clean filters monthly. Unplug devices on standby (phantom loads add 5-10%). Wash clothes in cold water. Run dishwasher and laundry at night (lower rates). Install solar panels for long-term savings.
What is the electricity rate in Sri Lanka?
Sri Lanka uses tiered pricing (more you use, higher rate per unit). Residential: 0-30 units: ~7.85/kWh. 31-60: ~10/kWh. 61-90: ~27.75/kWh. 91-120: ~32/kWh. Above 120: ~45-72/kWh. Industrial and commercial rates differ. Rates change periodically — check your latest bill for current rates.
Can solar panels eliminate my electricity bill?
Potentially yes. A properly sized solar system can offset most or all consumption. Net metering allows you to sell excess power back to the grid. In Sri Lanka, a 1kW solar system costs about 200,000-300,000 rupees and generates about 100-130 kWh per month. Payback period is typically 5-8 years.