How this calculator works
An appliance’s power rating in watts (W) tells you how fast it uses energy. Your utility bills you for energy in kilowatt-hours (kWh): one kWh is 1,000 watts used for one hour. The calculator applies these formulas to each appliance and adds them up:
kWh per day = watts ÷ 1,000 × hours used per day × quantity
kWh per month = kWh per day × days used per month
Monthly cost = kWh per month × electricity rate (₱/kWh)
Annual cost = monthly cost × 12 Worked example
Example (estimate). Two 60 W electric fans running 8 hours a day for 30 days, plus a 700 W rice cooker used for 1 hour a day, at an example rate of ₱15.06/kWh:
- Fans: 60 ÷ 1,000 × 8 × 2 = 0.96 kWh/day → 28.8 kWh/month → ₱433.73
- Rice cooker: 700 ÷ 1,000 × 1 × 1 = 0.7 kWh/day → 21 kWh/month → ₱316.26
- Total: 49.8 kWh/month → about ₱749.99/month
A rice cooker draws full power mainly while cooking and much less on “keep warm”, so the real figure is likely lower. That is why measured values beat label values.
Getting good inputs
Watts
Look for the rating plate or sticker on the appliance, the user manual, or the energy label. If the label only shows volts (V) and amps (A), multiply them for an upper estimate: watts ≈ volts × amps. A plug-in energy meter shows the real power draw and is the most reliable way to measure appliances that cycle on and off.
Hours and days
Be honest about usage. Ten minutes a day for a hair dryer is 0.17 hours. Appliances that are always plugged in, such as a Wi-Fi router, run 24 hours a day.
Your electricity rate
The calculator starts with an example rate of ₱15.06 per kWh. That is Meralco’s announced overall rate for a typical household using 200 kWh a month in October 2026 (₱15.0615/kWh), as reported by The Philippine Star on 14 October 2026.
It is only an example: rates differ by distribution utility and electric cooperative, by consumption level, and from month to month. For your own estimate, divide the total amount on your latest bill by the kWh shown on it.
Assumptions and limitations
- The appliance is assumed to draw its entered wattage for the whole time it is on. Many appliances (fridges, aircons, rice cookers, washing machines) don’t.
- One flat average rate is applied to every kWh. Real bills include fixed charges, subsidies, taxes and charges that vary with consumption.
- A month is whatever number of days you enter; annual cost is simply monthly × 12.
- Standby (“vampire”) power is only counted if you add it as its own row.
For a whole-house picture, use the household appliance inventory, which ranks your biggest users and exports a CSV. For aircons, the aircon cost calculator handles duty cycle and side-by-side scenarios.