How to Use Appliance Wattage Calculator
The Appliance Wattage Calculator supports two input modes.
Watts Direct (fromW)
- Enter Watts — Number from the nameplate.
- Enter Voltage — Usually 120 V in the US or 220-240 V elsewhere.
- Enter Power Factor — Default 0.95.
VA Direct (fromVA)
- Enter Voltage and Current — V and A from the spec plate.
- Enter Power Factor — Real power = V × A × power_factor.
After either mode, optionally enter hours per day and electricity price to see monthly kWh and cost.
Formula & Theory — Appliance Wattage Calculator
W = V × A × power_factor
VA = V × A
A = W ÷ (V × power_factor)
kWh_month = W × hours_per_day × 30 ÷ 1000
cost_month = kWh_month × price_per_kWh| Symbol | Meaning |
|---|---|
| W | Real power (watts) |
| VA | Apparent power (volt-amperes) |
| A | Current (amps) |
| power_factor | Ratio of real to apparent power |
| price_per_kWh | Electricity price per kWh |
Typical Power Factors
Resistive heaters / incandescent bulbs ~1.0
Modern LED / electronics 0.9–0.95
Older motors 0.7–0.8Use Cases for Appliance Wattage Calculator
- Energy Audits — Identify high-draw appliances at home.
- Generator Sizing — Sum VA loads to size a backup generator.
- Circuit Planning — Verify total amperage on a single breaker.
- Cost Forecasting — Estimate monthly cost of long-running devices.
- Solar Sizing — Convert appliance demand into kWh per day for off-grid sizing.
The Appliance Wattage Calculator turns confusing nameplate data into clear, actionable numbers.