How to calculate your electricity bill
kWh = (watts × hours per day × days) ÷ 1,000
cost = kWh × rate per kWh
Example: 1,500W space heater, 8 hrs/day, $0.16/kWh
- Daily kWh: (1,500 × 8) ÷ 1,000 = 12 kWh
- Monthly kWh: 12 × 30 = 360 kWh
- Monthly cost: 360 × $0.16 = $57.60
Electricity rates by state
Average residential electricity rates vary dramatically by state:
| State | $/kWh | Monthly bill (850 kWh) |
|---|---|---|
| Hawaii | $0.35 | $298 |
| California | $0.30 | $255 |
| Connecticut | $0.29 | $246 |
| Massachusetts | $0.28 | $238 |
| New York | $0.23 | $196 |
| New Hampshire | $0.22 | $187 |
| Rhode Island | $0.22 | $187 |
| Michigan | $0.18 | $153 |
| New Jersey | $0.17 | $145 |
| US Average | $0.16 | $136 |
| Illinois | $0.15 | $128 |
| Ohio | $0.14 | $119 |
| Texas | $0.14 | $119 |
| Florida | $0.13 | $111 |
| Georgia | $0.13 | $111 |
| North Carolina | $0.12 | $102 |
| Washington | $0.11 | $94 |
| Louisiana | $0.10 | $85 |
Appliance energy usage (at $0.16/kWh)
| Appliance | Watts | Hrs/day | kWh/mo | $/month |
|---|---|---|---|---|
| Central AC | 1,500 | 8 | 360.0 | $57.60 |
| Window AC | 900 | 8 | 216.0 | $34.56 |
| Electric heater | 1,500 | 6 | 270.0 | $43.20 |
| Water heater (electric) | 4,000 | 3 | 360.0 | $57.60 |
| Refrigerator | 150 | 24 | 108.0 | $17.28 |
| Clothes dryer | 5,000 | 1 | 150.0 | $24.00 |
| Electric oven | 2,000 | 1 | 60.0 | $9.60 |
| Dishwasher | 1,800 | 1 | 54.0 | $8.64 |
| Pool pump | 2,000 | 8 | 480.0 | $76.80 |
| TV (LED) | 100 | 5 | 15.0 | $2.40 |
| Desktop computer | 200 | 6 | 36.0 | $5.76 |
| Laptop | 60 | 8 | 14.4 | $2.30 |
| Washing machine | 500 | 1 | 15.0 | $2.40 |
| Microwave | 1,000 | 0.25 | 7.5 | $1.20 |
| Ceiling fan | 75 | 10 | 22.5 | $3.60 |
| LED bulb (×10) | 100 | 6 | 18.0 | $2.88 |
| Hair dryer | 1,800 | 0.1 | 5.4 | $0.86 |
| Coffee maker | 900 | 0.25 | 6.8 | $1.08 |
| EV charger (L2) | 7,200 | 4 | 864.0 | $138.24 |
| Dehumidifier | 500 | 12 | 180.0 | $28.80 |
How to read your electricity meter
Modern digital meters display your cumulative kWh reading directly. Record the reading on two dates (e.g., 1st and 30th of the month), subtract to get kWh used during that period. Analog dials: read left to right; if the pointer is between numbers, use the lower number. Smart meters transmit readings automatically to the utility and often display daily/hourly usage through a web portal or app.
Tips to lower your electric bill
- Switch to LED bulbs — 75% less energy than incandescent, last 10–25× longer. Saves $30–75/year per bulb.
- Install a smart thermostat — saves 10–23% on heating/cooling costs ($100–200+/year).
- Unplug phantom loads — game consoles, cable boxes, chargers. 50–200W constant = $6–23/month.
- Seal air leaks — weather strip doors, caulk windows. Cuts HVAC load by 10–20%.
- Use cold water for laundry — 90% of washer energy goes to heating water.
- Time-of-use rates — run dishwasher, laundry, EV charging during off-peak hours (nights/weekends). Saves 20–40% where available.
- Replace old appliances — Energy Star fridge, washer, dryer use 30–50% less than 15+ year-old models.
- Ceiling fans + AC together — allows you to set thermostat 4°F higher with the same comfort.
Understanding your electric bill
Your bill typically has three main parts:
- Energy charge — kWh used × rate per kWh. This is the biggest line item.
- Delivery / distribution charge — cost to bring power from the grid to your home. Fixed + per-kWh component. Often 25–50% of the total bill.
- Fixed monthly charge — $5–25/month service fee regardless of usage.
- Taxes and surcharges — state/local taxes, renewable energy surcharge, public benefit fees. 5–15% of total.
Your "effective rate" (total bill ÷ total kWh) is typically 20–40% higher than the advertised energy rate due to delivery and taxes. Use the effective rate for accurate calculations.
Electricity units explained
- Watt (W) — unit of power. A 100W bulb uses 100 watts of power when on.
- Kilowatt (kW) — 1,000 watts. A 1.5 kW heater = 1,500W.
- Kilowatt-hour (kWh) — unit of energy. 1 kW running for 1 hour = 1 kWh. This is what you're billed for.
- Amp (A) — unit of current. Household circuits are 15 or 20 amps.
- Volt (V) — unit of voltage. US outlets are 120V (240V for large appliances).
Relationship: Watts = Volts × Amps. Use our Watts/Amps/Volts Calculator for conversions.
Frequently asked questions
How do I calculate my electricity bill?
Calculate kilowatt-hours (kWh) used, then multiply by your rate. kWh = (watts × hours used) ÷ 1,000. Example: a 1,500W heater running 8 hours = (1,500 × 8) ÷ 1,000 = 12 kWh per day. Multiply by 30 for monthly (360 kWh) and by your rate (e.g., $0.16/kWh) = $57.60/month. Sum all appliances for your total bill. Our calculator handles this for any number of devices.
What is a kilowatt-hour (kWh)?
A kilowatt-hour is the unit your electric company uses for billing — it's the energy used by 1,000 watts running for 1 hour. A 100W bulb for 10 hours = 1 kWh. A 1,500W hair dryer for 10 minutes = 0.25 kWh. The US average household uses 850 kWh per month at ~$0.16/kWh = ~$136/month. Your bill has a total kWh figure — compare to your calculated appliance usage.
How much does it cost to run an air conditioner?
A central AC (1,500W) running 8 hours/day uses 360 kWh per month, costing $57.60 at $0.16/kWh. A window AC (900W) running 8 hours = 216 kWh = $34.56/month. Higher usage (12+ hours during summer) doubles these numbers. SEER rating matters: a 20 SEER AC uses 30% less than a 14 SEER at the same cooling output. Set thermostat to 78°F when home, 85°F when away to cut costs ~10% per degree.
What uses the most electricity in a home?
In order of typical monthly usage: (1) HVAC (heating/cooling) — 40–60% of bill, (2) water heater — 15–20%, (3) refrigerator — 5–10%, (4) clothes dryer — 5–10%, (5) lighting — 5–10%, (6) TVs and electronics — 5%. High-end energy hogs: EV charging (7.2 kW for 4 hrs = 864 kWh/month = $138), pool pumps (2 kW for 8 hrs = 480 kWh = $77), and electric dryers (5 kW for 1 hr × 20 loads = 100 kWh = $16).
What is the average electric bill in the US?
The US average monthly electric bill is approximately $136 (as of 2025 data from EIA). This covers ~850 kWh at ~$0.16/kWh. Bills vary widely by state: Hawaii averages $200+ (highest rates), Louisiana and Washington around $100–120 (cheapest rates + efficient homes). Larger homes with central AC, pools, and EVs can easily exceed $300/month. Apartment dwellers often pay $50–80.
How many watts does a refrigerator use?
Modern Energy Star refrigerators use 100–250 watts while running, but only run about 30% of the time (compressor cycles). Average daily consumption: 3–5 kWh (~$0.50–0.80/day at $0.16/kWh). Monthly: 90–150 kWh (~$15–24). Older refrigerators (pre-2000) can use 2–3× as much. Check the yellow EnergyGuide label for the exact annual kWh. Side-by-side models use more than top-freezer models.
How do I find my electricity rate?
Check your electric bill — look for 'energy charge' or 'supply rate' in $/kWh. Typical US rates are $0.10–0.35/kWh. Some utilities show a simple per-kWh rate; others have tiered rates (first 500 kWh at $0.12, above 500 kWh at $0.18) or time-of-use rates (peak $0.30, off-peak $0.08). For accurate calculations, add delivery charges and taxes — these can add 20–40% to the base energy rate. Your 'effective rate' is total bill ÷ total kWh used.
Does turning off lights save electricity?
Yes, but LED lights use so little power the savings are modest. A 10W LED for 10 hours = 0.1 kWh = $0.016/day = $6/year. Turning off for 4 of those hours saves $2.40/year. For incandescent bulbs (mostly phased out), savings are 10× higher. Bigger savings come from turning off AC, computers, TVs, and heaters. The old 'turn off lights when leaving a room' advice still applies — it's just not the biggest win anymore.
How much electricity does a TV use?
Modern LED/LCD TVs use 50–150 watts depending on size (32" ~50W, 55" ~100W, 75" ~150W). OLED TVs vary more — 80–250W based on brightness and content. Average 5 hours/day for a 55" TV (100W): 15 kWh/month = $2.40/month. Plasma TVs (older) use 2–3× more. Standby mode adds $1–3/year. Biggest impact: TV size and brightness settings. Check the yellow EnergyGuide label for exact annual kWh.
What is a phantom load?
Phantom load (or vampire power) is electricity consumed by devices in standby mode — TVs, microwaves with clocks, game consoles, chargers plugged in without a device. Typical household phantom load: 50–200W constantly = 36–144 kWh/month = $6–23/month. Use smart power strips that shut off peripherals when the main device is off. Worst offenders: cable/satellite boxes (25W always), game consoles (10W), smart speakers (3W each), wall warts (1–5W each).
How do I convert watts to kWh?
kWh = (watts × hours) ÷ 1,000. A 100W bulb for 10 hours = (100 × 10) ÷ 1,000 = 1 kWh. For a full month: multiply hours per day × 30 days. A 200W desktop on 8 hours/day × 30 days = (200 × 8 × 30) ÷ 1,000 = 48 kWh/month. Use our calculator for any wattage and time period.
How much does it cost to charge an electric car?
Depends on battery size and rate. A Tesla Model 3 Long Range (82 kWh battery) fully charged at $0.16/kWh = $13.12. Driving ~300 miles = 4.4¢/mile vs gas at ~12¢/mile (savings ~$100/month for typical drivers). Level 2 home chargers (240V, 30–50A) draw 7,200W — 4 hours to add 100 miles of range costs ~$4.60. Fast DC chargers at public stations cost more ($0.30–0.60/kWh) but are faster.