Electricity Cost Calculator
Electricity cost calculation bridges the gap between a piece of equipment's nameplate wattage and the real dollars it extracts from your utility budget. The fundamental equation...
Formula
Source: EIA, EPA Energy Star, DOE Building Energy Data Book | Last reviewed: July 26, 2026
Examples
1500 W
= 43.2 kWh
- hours_per_day = 8
- days_per_month = 30
- rate = 0.12
1,500W heater 8h/day = $43.20/month
75000 W
= 3780 kWh
- hours_per_day = 24
- days_per_month = 30
- rate = 0.07
75 kW motor 24/7 at industrial rate = $3,780/month
12 W
= 6.31 kWh
- hours_per_day = 12
- days_per_month = 365
- rate = 0.12
12W LED bulb 12h/day = $6.31/year
Quick Reference Table
| Sector/Region | Average Rate ($/kWh) | Annual Cost at 1,000 kWh/Month |
|---|---|---|
| Residential - US Average | 0.165 | $1,980 |
| Residential - Pacific Northwest | 0.089 | $1,068 |
| Residential - California | 0.320 | $3,840 |
| Residential - Hawaii | 0.442 | $5,304 |
| Residential - New England | 0.260 | $3,120 |
| Commercial - US Average | 0.125 | $1,500 |
| Industrial - US Average | 0.075 | $900 |
Popular Conversions
Quick answers for the most-searched W to kWh values.
How much does it cost to run a 1500W heater 8 hours a day
1500 W = 43.2 kWh
1,500W space heater, 8h/day, 30 days at $0.12/kWh = $43.20/month. Electric resistance heating is expensive - a heat pump at COP 3.0 costs only $14.40/month for the same heat.
Cost to run central AC per month
3500 W = 100.8 kWh
3.5 kW (4-ton) central AC running 8h/day at $0.12/kWh = $100.80/month. In hot climates with 12-16h runtime in summer months, expect $150-200/month.
How much does it cost to run a 75 kW motor 24/7
75000 W = 3780 kWh
75 kW (100 HP) industrial motor running 24/7/365 at $0.07/kWh industrial rate = $3,780/month = $45,990/year. This is why motor efficiency matters - 2% improvement saves $920/year.
LED vs incandescent lighting cost
60 W = 0.52 kWh
60W incandescent bulb 5h/day = $1.08/month. Equivalent 9W LED = $0.16/month. Savings: $0.92/month per bulb. Over 50 bulbs in a commercial office, that's $552/year.
Cost to charge an EV at home
7200 W = 17.28 kWh
7.2 kW Level 2 charger, 2 hours nightly (14.4 kWh/day), 30 days at $0.12/kWh = $51.84/month. Compare to $175/month for gasoline at 15,000 mi/yr.
Where is this used?
(1) Residential appliance audit: A homeowner with a 200W television used 6 hours/day, a 1,500W space heater used 4 hours/day, a 4,500W water heater operating 3 hours/day, and a 200W refrigerator cycling 8 hours/day can calculate monthly costs: TV = $4.32, heater = $21.60, water heater = $48.60, refrigerator = $5.76, totaling $80.28/month at $0.12/kWh.
Comparing against the actual bill identifies discrepancies from phantom loads, meter errors, or unaccounted usage.
(2) Industrial motor replacement economics: A 100 HP (75 kW) motor running 8,000 hours/year at $0.07/kWh consumes $42,000/year in electricity.
Upgrading from standard efficiency (91.7%) to NEMA Premium (95.4%) saves approximately 75 x 8,000 x $0.07 x (1/0.917 - 1/0.954) = $1,770/year.
The premium motor's $2,000 cost premium pays back in 14 months, producing 20-year net savings of approximately $33,400.
(3) HVAC annual cost projection: Using cooling degree-days and the AC's SEER rating to estimate annual kWh, then multiplying by the local rate.
A 4-ton SEER 15 AC in Dallas (2,500 CDD) consumes approximately 7,680 kWh/year for cooling, costing $922/year at $0.12/kWh.
(4) Data center energy budget: A 100 kW IT load data center with a PUE of 1.6 consumes 1,401,600 kWh/year.
At $0.08/kWh industrial rate, annual electricity cost is $112,128 — often the single largest operating expense after staffing.
Reducing PUE from 1.6 to 1.2 saves 350,400 kWh ($28,032/year).
(5) Lighting retrofit payback: Replacing 400W metal halide high-bay fixtures (455W with ballast) with 150W LED fixtures in a 100-fixture warehouse operating 6,000 hours/year saves (455 - 150) x 100 x 6,000 / 1,000 = 183,000 kWh/year.
At $0.10/kWh, that's $18,300/year savings.
(6) Residential solar feasibility: A 12,000 kWh/year home at $0.18/kWh spends $2,160/year.
A 10 kW solar array in a 4.5 sun-hour location produces ~13,500 kWh/year, worth $2,430/year.
The $25,000 system (after 30% federal tax credit: $17,500 net) pays back in 7.2 years.
(7) EV home charging annual cost: 4,000 kWh/year (15,000 miles at 3.75 mi/kWh) at residential rate $0.12/kWh = $480/year.
Versus gasoline at 30 MPG and $3.50/gallon = $1,750/year — annual savings of $1,270.
(8) Server room and crypto mining profitability analysis: A 3 kW mining rig running 24/7 consumes 2,160 kWh/month.
At $0.10/kWh, monthly electricity cost is $216.
Revenue must exceed this plus amortized hardware cost to achieve profitability — explaining why commercial miners locate in regions with very cheap electricity (<$0.05/kWh, such as parts of Texas and Washington).
Real-World Usage Scenarios
Homeowner HVAC Bill Shock Investigation
A family in Phoenix, AZ noticed their July electricity bill reached $485 when it normally averages $220. Using the calculator: their 5-ton SEER 14 AC draws 4.3 kW running. At 14 hours/day runtime during a 115 degree F heat wave on the APS rate of $0.135/kWh: 4.3 kW x 14h x 31 days x $0.135 = $251.91 for cooling alone. The remaining $233 accounts for pool pump (1.5 kW x 8h = $50.22), water heating ($45), refrigeration ($35), and other base loads ($103). The audit revealed the AC had a refrigerant leak reducing its capacity, forcing longer runtimes and increasing compressor energy consumption. A $350 repair restored efficiency, reducing cooling cost to approximately $170/month — savings of $82/month that paid back the repair in just over 4 months.
Manufacturing Plant Compressed Air Cost Discovery
A plant engineer evaluated the facility's 200 HP air compressor running 6,000 hours/year. At 150 kW average load and $0.065/kWh industrial rate, annual electricity cost = 150 kW x 6,000h x $0.065 = $58,500. A compressed air system audit found 35% of compressed air was wasted through leaks (equivalent to a 1/4-inch hole at 100 PSI leaking $8,500/year), inappropriate uses such as open blow-off and chip cleaning ($6,000/year), and artificial demand from operating at 110 PSI when 95 PSI was sufficient ($3,400/year). Fixing leaks and reducing pressure setpoint from 110 PSI to 95 PSI saved 52,000 kWh/year ($3,380). Replacing pneumatic blow-off nozzles with engineered air nozzles saved another 18,000 kWh ($1,170). Total savings: $4,550/year with a one-time implementation cost of $8,000 — an attractive 1.8-year payback with ongoing savings thereafter.
Small Restaurant Energy Benchmarking and Optimization
A 1,500 sq ft restaurant operating with a walk-in cooler (2 kW, 60% duty cycle), commercial freezer (1.5 kW, 70% duty cycle), electric griddle (4 kW, 6 hours/day), two electric fryers (3 kW each, 5 hours/day), 5-ton HVAC (5 kW, 6 hours/day), and LED lighting (2 kW, 12 hours/day) at $0.14/kWh commercial rate. Monthly energy consumption: cooler = 864 kWh ($121), freezer = 756 kWh ($106), griddle = 720 kWh ($101), fryers = 900 kWh ($126), HVAC = 900 kWh ($126), lighting = 720 kWh ($101), water heating = 600 kWh ($84), miscellaneous = 350 kWh ($49). Total: 5,810 kWh/month or $814/month. The area benchmark for similar restaurants is $0.35/sq ft/month = $525, indicating 55% higher energy intensity. Installing programmable thermostats ($400), door gaskets for refrigeration ($300), and occupancy sensors for restroom/storage lighting ($200) — a $900 investment — saved an estimated $150/month for a 6-month payback.
Common Mistakes to Avoid
Confusing watts with kilowatts when entering data
The most common input error is manually dividing wattage by 1,000 before entering it — and then the calculator dividing again, producing a result 1,000x too low. The calculator expects the raw wattage and handles the division internally. Enter '1500' for a 1,500-watt device — do not enter '1.5'. Conversely, for large equipment rated in kW, convert to watts: a 75 kW motor is entered as 75,000 watts. Always check that your result is in the right order of magnitude — a 1,500W heater running all month should cost roughly $40-60, not $0.04.
Ignoring duty cycle for cycling appliances
Refrigerators, air conditioners, well pumps, and air compressors do not run continuously. A refrigerator nameplated at 200W typically has a compressor that runs only 40% of the time (~9.6 hours/day). A central AC might cycle 50-70% during summer afternoons. Using continuous 24-hour operation for a cycled appliance overstates the cost by 2-3x. For accurate measurement, use a plug-in energy meter (e.g., Kill-A-Watt EZ, approximately $30) over a 24-72 hour period to determine actual daily kWh consumption and back-calculate the effective duty cycle.
Using the wrong electricity rate for your customer class
Residential ($0.12-0.35/kWh), commercial ($0.08-0.18/kWh), and industrial ($0.05-0.10/kWh) customers pay fundamentally different rates. Within residential, many utilities offer time-of-use (TOU) rates where electricity costs $0.05/kWh at night and $0.30-0.50/kWh during summer peak hours (4-9 PM). For EV owners, charging on-peak vs off-peak can differ by 6x. Always use the actual rate from your utility bill — look for total bill amount divided by total kWh consumed to get the all-in average rate. For commercial and industrial customers, demand charges ($/kW of peak demand) can add 20-40% above energy ($/kWh) charges, and this calculator does not include demand charges — consult your rate schedule for total cost.
Industry Standards Referenced
Frequently Asked Questions
How do I calculate the cost of running an appliance?
Find the appliance wattage from the nameplate or a plug-in power meter such as a Kill-A-Watt. Estimate actual hours of use per day. Multiply: (Watts / 1000) x hours/day x days/month x $/kWh rate. Example: a 200W television used 5 hours/day: (0.2 kW) x 5h x 30 days x $0.12 = $3.60/month. For appliances that cycle (refrigerator, air conditioner, dehumidifier), use a power meter to measure actual daily kWh consumption over a 48-72 hour test period, or estimate the duty cycle based on the appliance's operational pattern. A refrigerator compressor typically runs 30-50% of the time in a climate-controlled home.
What is the average electricity rate in the US?
The US average residential rate is approximately $0.16-0.17/kWh as of 2025 (EIA Electric Power Monthly), with wide variation by state and region. Industrial rates are significantly lower at $0.06-0.08/kWh. Highest residential rates: Hawaii ($0.40-0.44/kWh), California ($0.30-0.35/kWh), Connecticut and Massachusetts ($0.28-0.32/kWh), Alaska ($0.24-0.26/kWh). Lowest residential rates: Washington ($0.08-0.10/kWh, hydro), Louisiana ($0.10-0.12/kWh, natural gas), Idaho ($0.09-0.11/kWh, hydro). Check your utility bill for your exact rate — the all-in average price is total bill amount divided by total kWh consumed. Time-of-use rates can range from $0.05/kWh (off-peak overnight) to $0.50+/kWh (summer peak 4-9 PM).
How much does it cost to run a central air conditioner?
A 4-ton (48,000 BTU/hr) central AC with a SEER rating of 15 draws approximately 3.2 kW while the compressor is running. At $0.12/kWh and 8 hours of actual compressor runtime per day (cycling on/off during a hot day): 3.2 kW x 8h x 30 days x $0.12 = $92/month. In hot climates such as Phoenix, Las Vegas, and Houston, AC can run 12-16 hours/day during July and August, pushing the monthly cooling cost to $150-200. A high-SEER unit (SEER 20 vs 15) reduces power draw by approximately 25%, saving $23-50/month. The SEER upgrade premium of $1,500-3,000 typically pays back in 3-5 years through electricity savings. For an accurate estimate, use your unit's actual SEER and the cooling degree-days for your climate zone.
What are phantom loads and how much do they cost?
Phantom loads (also called vampire loads, standby power, or idle load) are electricity consumed by devices when they appear to be 'off' or in standby mode. Common contributors: cable/satellite set-top boxes (25-45W continuous = $26-47/year at $0.12/kWh — often the single largest phantom load), video game consoles in standby/instant-on mode (10-15W = $10-16/year), televisions in standby (1-5W = $1-5/year), microwave oven clock display (2-5W = $2-5/year), and phone/laptop chargers left plugged in without a device connected (0.1-0.5W each — individually negligible but cumulatively can reach $5-10/year with many chargers). The average US home has 40+ devices always drawing some power, collectively consuming 200-400 kWh/year ($24-48/year). Using smart power strips that automatically cut power to peripheral devices when the main device is off can recover 50-100 kWh/year in savings.
How does power factor affect my electricity bill for industrial equipment?
For residential customers, power factor does not affect billing — residential meters measure only real power (kW and kWh). For commercial and industrial customers, many utilities impose a power factor penalty when the monthly average power factor falls below a specified threshold (typically 0.85-0.95). The billing adjustment is: billing demand (kW) = measured kW x (target PF / actual PF). So if measured demand is 100 kW at 0.70 PF and the target is 0.90, billing demand becomes 100 x (0.90/0.70) = 128.6 kW — a 28.6% penalty on the demand charge portion of the bill. Since demand charges can be $5-15/kW/month, a 28.6% penalty on 100 kW demand adds $143-429/month. Power factor correction capacitors typically cost $25-40/kVAR and pay back in 1-3 years, while also reducing I squared R losses in facility wiring by lowering total current draw. For motors, power factor is lowest at no load (0.1-0.2) and highest at full load (0.80-0.90) — oversizing motors degrades facility power factor.
Reviewed for accuracy
Reviewed against EIA 2025 Electric Power Monthly data and ENERGY STAR appliance energy use benchmarks · Last reviewed: July 26, 2026
All calculations are for reference only. Always verify with manufacturer data and a qualified engineer for critical applications. Learn about our editorial process.