Appliance Running Cost Calculator
Estimate daily, monthly, and yearly electricity cost for any appliance.
Appliance Running Cost Calculator
Appliance running cost estimates how much you pay to operate a device from its wattage, how long it runs each day, and your electricity rate. The result is daily, monthly, and yearly cost plus monthly kilowatt-hours consumed.
This is the simplest bill-building block: watts × hours gives watt-hours, divided by 1,000 for kWh, multiplied by your $/kWh rate. Use it for space heaters, AC units, fridges, gaming PCs, pool pumps, or any load where you know—or can measure—power and duty cycle.
Enter a flat rate from your utility bill or solar net-metering credit. For tiered or time-of-use tariffs, use a representative average rate here, or use the electricity bill calculator for full tier modeling.
How this calculator works
- Enter appliance watts from the nameplate, manual, or a plug-in power meter.
- Enter hours per day the appliance runs on average—not always 24 unless it is truly continuous.
- Enter your electricity rate in $/kWh from your bill (total cost ÷ kWh used, or your supply rate).
- Set days per month (default 30) for monthly and yearly projections.
- Daily kWh = (W × h) ÷ 1000. Costs = kWh × rate for daily, monthly (× days), and yearly (× 12 months).
Core cost relationships
Daily kWh = (W × h/day) ÷ 1000 | Cost = kWh × $/kWh | Yearly ≈ monthly × 12
Power in watts times runtime in hours gives watt-hours of energy per day. Dividing by 1,000 converts to kilowatt-hours, the unit utilities bill. Multiplying kWh by your rate gives cost. Monthly scales by days per month; yearly assumes 12 similar months—seasonal AC or heating may differ winter vs summer.
Formulas used by this tool
- Daily kWh = (watts × hours per day) ÷ 1000.
- Monthly kWh = daily kWh × days per month.
- Costs = kWh × your $/kWh rate for each period.
Worked example: 1,500 W heater
A 1,500 W space heater runs 4 hours per day at $0.16/kWh, 30 days per month.
- Daily kWh = (1,500 × 4) ÷ 1,000 = 6 kWh.
- Daily cost = 6 × $0.16 = $0.96.
- Monthly kWh = 6 × 30 = 180 kWh → monthly cost = $28.80.
- Yearly cost ≈ $28.80 × 12 = $345.60 if usage stays constant all year.
Practical tips
- Use a kill-a-watt meter for fridges and tools—nameplate watts are often peak, not average.
- Cycling loads (AC, fridge) need average hours on, not 24 h unless compressor runs constantly.
- Divide total bill kWh cost by usage to get an effective $/kWh if you have tiered rates.
- Compare before/after upgrades: LED vs incandescent, old vs new AC SEER rating.
- Off-grid users can enter solar opportunity cost or generator fuel equivalent as $/kWh.
Frequently asked questions
How do I find watts for my appliance?
Check the label or manual for rated watts. For variable loads, use a plug-in energy meter over a day or week. Many devices list amps and volts instead—multiply V × A for approximate watts (or use our amps-to-watts calculator).
What rate should I enter?
Use your marginal $/kWh—the cost of one more kilowatt-hour. On a simple bill, divide energy charges by kWh used. Exclude fixed monthly fees from the per-kWh rate unless you want to allocate them. For TOU plans, use the rate for the hours the appliance runs.
Why divide by 1,000?
Utility bills charge in kilowatt-hours (kWh), not watt-hours. One kWh = 1,000 Wh. A 1,000 W device running 1 hour uses 1 kWh.
Is yearly cost exact?
Yearly = monthly × 12, assuming every month matches your inputs. Real bills vary with seasons, rate changes, and holidays. Adjust hours per day seasonally for HVAC for better accuracy.
Does this include taxes and fixed charges?
No. This is energy cost only: kWh × rate. Fixed connection fees, demand charges, and tax are not included. Use the electricity bill calculator for tiered energy plus fixed charges and tax.
Can I compare solar offset savings?
Yes. Enter the same appliance data with your grid $/kWh rate—the result is what you avoid when solar covers that load. For self-consumption value, use your retail rate; for export credits, use your feed-in tariff rate.
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