How the electricity cost calculator works
The formula (it's short)
Cost = watts ÷ 1,000 × hours × rate. A 1,500-watt space heater running 3 hours at 16¢/kWh: 1.5 × 3 × $0.16 = 72¢/day ≈ $22/month of daily use. The calculator extends it to monthly and annual figures, because that's where appliance decisions actually get made.
Finding the honest wattage
- Nameplate watts are peak, not average. A fridge rated 1,200W compressor-start averages 100–200W across the day because it cycles. Our presets use realistic averages for cycling appliances.
- For precision, measure: a $15 plug-in power meter reads real consumption — the end of guessing for the appliance you suspect most.
- Your rate is on the bill: total charges ÷ total kWh = your effective rate. Headline rates exclude delivery charges, which are often half the bill.
The hall of fame (and shame)
Resistance heat anything — space heaters, dryers, water heaters — dominates household electricity cost per hour of use. Meanwhile, modern LED lighting and electronics have become rounding errors. The garage fridge is the classic middle case: $15–20/month to chill beer 30 feet from the kitchen fridge. The calculator tells you which side of that line every appliance lives on.