This appliance energy calculator turns any appliance’s wattage and daily use into kWh and running costs — per day, month and year — so the vampire loads in your home identify themselves.

kWh / Day–
Cost / Day–
Cost / Month–
Cost / Year–

Duty cycles hide inside “hours”: fridges and water heaters cycle their elements, so their nameplate watts × clock hours overstates — use average draw (fridge preset) or measured duty. The definitive answer comes from a $25 plug meter (Kill A Watt style) over a week — this calculator turns that reading into money.

kWh = Watts × Hours ÷ 1,000 — then Multiply by Your Rate

The whole-house view of the same money lives on our Electricity Cost Calculator; this page itemizes it appliance by appliance, where the savings hide. Part of our Ecology Calculators collection.

Worked Example (Verified)

  • 1,500 W AC × 8 h/day at $0.17 (defaults): 12 kWh/day → $2.04/day, $61/month, $745/year if run daily — the seasonal appliance that writes summer bills
  • Fridge perspective: 120 W average × 24 h = 2.88 kWh/day ≈ $0.49 — always-on beats big-but-brief in the annual ledger more often than intuition says
  • The gaming rig: 200 W × 4 h = 0.8 kWh = $0.14/day — cheap hobby; its 1,000 W sibling (mining-era habits) at 24 h would be $4.08/day
  • Standby math: a 5 W vampire × 24 × 365 = 43.8 kWh ≈ $7.45/yr — trivial alone, and homes harbor 20–40 of them

Finding Your Real Numbers

  • Nameplate watts = maximum draw, not average: motors and heaters cycle; compressors surge at startup.
  • Labels to trust: EnergyGuide yearly kWh (measured duty built in) and plug-meter readings over representative days.
  • Rates vary 3× across US states ($0.11–0.35+) — your bill’s all-in $/kWh (energy + delivery + fees) is the honest rate input.
  • Time-of-use plans change the rate by hour: shift the dryer/EV/dishwasher, not the lifestyle.

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Frequently Asked Questions

How do I calculate an appliance’s electricity cost?

kWh per day = watts × hours ÷ 1,000; multiply by your rate. A 1,500 W air conditioner running 8 hours uses 12 kWh — at $0.17/kWh that’s $2.04/day or ~$61/month. This calculator adds month/year views and presets for common appliances.

How many watts does a refrigerator use?

Modern fridges draw 100–200 W while the compressor runs, cycling to average roughly 1–2.5 kWh/day total (EnergyGuide labels state the yearly figure directly — divide by 365). The preset here uses 120 W average draw × 24 h ≈ 2.88 kWh/day, the upper-middle of the modern range.

What uses the most electricity in a home?

Typically heating/cooling first (space heaters and AC at 1,500 W+ with long hours), then water heating, then dryers and ovens — high watts × real hours. Lighting used to rank; LEDs demoted it. This calculator’s presets are ordered to hunt the big three first.

Is it cheaper to run appliances at night?

Only on time-of-use tariffs, where off-peak rates can run 30–60% lower — flat-rate customers gain nothing by shifting. Check your tariff type before reorganizing laundry around midnight; on the right plan, the dryer and EV are the two loads worth scheduling.

How much do standby loads really cost?

Each 1 W of always-on draw = 8.76 kWh/year ≈ $1.50 at $0.17. Individual vampires (chargers, TVs, consoles) run 2–10 W; whole-home standby commonly totals 50–100 W = $75–150/yr. Smart strips on entertainment clusters are the surgical fix.

Is this appliance energy calculator free?

Yes — free, instant, no sign-up.